Ado.net[登录，增删改查，Get传值,全选，不选，批量删除,批量更新]

[虽然说，开发的时候，我们可以使用各种框架，ado.net作为底层的东西，作为一个合格的程序员，在出问题的时候我们还是要知道如何调试]

一、增删改查

cmd.ExecuteReader();执行查询,所有sql语句的查询都用这个方法;

      cmd.ExecuteNonQuery();执行所有sql语句的增删改都用这个方法;

  1       <div>
           <table>
               <tr>
                   <td> 用户名:</td>
                   <td>
                       <asp:TextBox ID="txtSUserName" runat="server"></asp:TextBox>
                   </td>
                   <td>班级：</td>
                   <td>
                       <asp:DropDownList ID="ddlselPhase" runat="server">
                           <asp:ListItem>---请选择---</asp:ListItem>
                           <asp:ListItem>.NET高级班01期</asp:ListItem>
                           <asp:ListItem>.NET高级班02期</asp:ListItem>
                           <asp:ListItem>.NET讲师</asp:ListItem>
                           <asp:ListItem>.NET网站开发01期</asp:ListItem>
                           <asp:ListItem>.NET网站开发02期</asp:ListItem>
                           <asp:ListItem>.NET网站开发03期</asp:ListItem>
                           <asp:ListItem>.NET网站开发04期</asp:ListItem>
                           <asp:ListItem>.NET网站开发05期</asp:ListItem>
                           <asp:ListItem>.NET网站开发06期</asp:ListItem>
                           <asp:ListItem>.NET网站开发07期</asp:ListItem>
                           <asp:ListItem>.NET网站开发08期</asp:ListItem>
                           <asp:ListItem>.NET网站开发09期</asp:ListItem>
                           <asp:ListItem>.NET网站开发10期</asp:ListItem>
                           <asp:ListItem>.NET网站开发11期</asp:ListItem>
                           <asp:ListItem>.NET网站开发12期</asp:ListItem>
                           <asp:ListItem>.NET网站开发13期</asp:ListItem>
                           <asp:ListItem>.NET网站开发14期</asp:ListItem>
                           <asp:ListItem>.NET网站开发15期</asp:ListItem>
                           <asp:ListItem>.NET网站开发16期</asp:ListItem>
                           <asp:ListItem>java第一期</asp:ListItem>
                           <asp:ListItem>JAVA讲师</asp:ListItem>
                           <asp:ListItem>ps设计01期</asp:ListItem>
                           <asp:ListItem>ps设计02期</asp:ListItem>
                           <asp:ListItem>ps设计03期</asp:ListItem>
                           <asp:ListItem>网页前端01期</asp:ListItem>
                       </asp:DropDownList>
                   </td>
                   <td>
                       <asp:Button ID="btnSel" runat="server" Text="查询" OnClick="btnSel_Click" />
                   </td>
               </tr>
           </table>
        </div>
        <div>
             <table>
               <tr>
                   <td> 用户名:</td>
                   <td>
                       <asp:TextBox ID="txtAddUserName" runat="server"></asp:TextBox>
                   </td>
                   <td> 密码:</td>
                   <td>
                       <asp:TextBox ID="txtAddPwd" runat="server" TextMode="Password"></asp:TextBox>
                   </td>
                   <td> QQ:</td>
                   <td>
                       <asp:TextBox ID="txtAddQq" runat="server"></asp:TextBox>
                   </td>
                   <td>班级：</td>
                   <td>
                       <asp:DropDownList ID="ddlAddPhase" runat="server">
                           <asp:ListItem>---请选择---</asp:ListItem>
                           <asp:ListItem>.NET高级班01期</asp:ListItem>
                           <asp:ListItem>.NET高级班02期</asp:ListItem>
                           <asp:ListItem>.NET讲师</asp:ListItem>
                           <asp:ListItem>.NET网站开发01期</asp:ListItem>
                           <asp:ListItem>.NET网站开发02期</asp:ListItem>
                           <asp:ListItem>.NET网站开发03期</asp:ListItem>
                           <asp:ListItem>.NET网站开发04期</asp:ListItem>
                           <asp:ListItem>.NET网站开发05期</asp:ListItem>
                           <asp:ListItem>.NET网站开发06期</asp:ListItem>
                           <asp:ListItem>.NET网站开发07期</asp:ListItem>
                           <asp:ListItem>.NET网站开发08期</asp:ListItem>
                           <asp:ListItem>.NET网站开发09期</asp:ListItem>
                           <asp:ListItem>.NET网站开发10期</asp:ListItem>
                           <asp:ListItem>.NET网站开发11期</asp:ListItem>
                           <asp:ListItem>.NET网站开发12期</asp:ListItem>
                           <asp:ListItem>.NET网站开发13期</asp:ListItem>
                           <asp:ListItem>.NET网站开发14期</asp:ListItem>
                           <asp:ListItem>.NET网站开发15期</asp:ListItem>
                           <asp:ListItem>.NET网站开发16期</asp:ListItem>
                           <asp:ListItem>java第一期</asp:ListItem>
                           <asp:ListItem>JAVA讲师</asp:ListItem>
                           <asp:ListItem>ps设计01期</asp:ListItem>
                           <asp:ListItem>ps设计02期</asp:ListItem>
                           <asp:ListItem>ps设计03期</asp:ListItem>
                           <asp:ListItem>网页前端01期</asp:ListItem>
                       </asp:DropDownList>
                   </td>
                   <td>
                       <asp:Button ID="btnAdd" runat="server" Text="添加" OnClick="btnAdd_Click" style="height: 21px" />
                   </td>
               </tr>
           </table>
         </div>
        <div>
             <table>
                 <tr>
                     <td>用户ID:</td>
                     <td>
                         <asp:TextBox ID="txtDUId" runat="server"></asp:TextBox>
                     </td>
                     <td>
                         <asp:Button ID="btnD" runat="server" Text="删除" OnClick="btnD_Click" />
                     </td>
                 </tr>
             </table>
         </div>
        <div>
            <table>
                <tr>
                    <td>ID:</td>
                    <td>
                        <asp:TextBox ID="txtUId" runat="server"></asp:TextBox>
                    </td>
                    <td>
                        <asp:TextBox ID="txtUUserName" runat="server"></asp:TextBox>
                    </td>
                    <td>
                        <asp:Button ID="btnU" runat="server" Text="更新" OnClick="btnU_Click" />
                    </td>
                </tr>
            </table>
        </div>
        <div>
         <asp:GridView ID="GriVShow" runat="server" AutoGenerateColumns="False">
             <Columns>
                 <asp:BoundField DataField="Userid" HeaderText="用户ID" />
                 <asp:BoundField DataField="UserName" HeaderText="用户名：" />
                 <asp:BoundField DataField="phonenum" HeaderText="电话号码" />
                 <asp:BoundField DataField="sex" HeaderText="性别" />
                 <asp:BoundField DataField="phase" HeaderText="班级" />
                 <asp:BoundField DataField="qq" HeaderText="QQ" />
                 <asp:BoundField DataField="Message" HeaderText="信息" />
                 <asp:BoundField DataField="HeadPic" HeaderText="头像" />
                 <asp:BoundField DataField="CreatedTime" HeaderText="创建时间" />
                 <asp:TemplateField HeaderText="详情">
                     <ItemTemplate>
                         <a href="UserInforManagerContext.aspx?Id=<%#Eval("UserId")%>">详情</a>
                     </ItemTemplate>
                 </asp:TemplateField>
             </Columns>
         </asp:GridView>
     </div>

   public partial class UserInforManager : System.Web.UI.Page
     {
         string constr = ConfigurationManager.ConnectionStrings["sq_r"].ToString();
         SqlConnection con = null;
         SqlCommand cmd = null;
         SqlDataReader read = null;
         protected void Page_Load(object sender, EventArgs e)
         {
             if (!(IsPostBack))
             {
                 BindUserInfor();
             }
         }
         /// <summary>
         /// 数据绑定
         /// </summary>
         public void BindUserInfor()
         {
             try
             {
                 //string strstring = "select Userid,UserName,phonenum,sex,phase,qq,Message,HeadPic,CreatedTime from UserInfor where 1=1";
                 using (con = new SqlConnection(constr))
                 {
                     con.Open();
                     cmd = new SqlCommand(GetSql(), con);
                     using (read = cmd.ExecuteReader())
                     {
                         //开始读以上sql数据,这句话一定要有，如果把它取出来的话是需要读的，但是这地方我只想它把内容赋值给gridview
                         //if (read.Read())
                         //{
                         //}
                         //但是这地方我只想它把内容赋值给gridview
                         //内容取出来之后，我希望有东西可以接收它的内容
                         GriVShow.DataSource = read;
                         GriVShow.DataBind();
                     }
                 }
             }
             catch (Exception ex)
             {
                 Response.Write("<script>alret('系统正在维护，请联系管理员!');</script>");
             }
         }

         protected void btnSel_Click(object sender, EventArgs e)
         {
             BindUserInfor();
         }
         /// <summary>
         /// 获取SQL
         /// </summary>
         /// <returns></returns>
         public string GetSql()
         {
             //string username = txtSUserName.Text.Trim();
             //string phase = ddlselPhase.SelectedValue;
             StringBuilder sb = new StringBuilder();
             sb.Append("select Userid,UserName,phonenum,sex,phase,qq,Message,HeadPic,CreatedTime from UserInfor where 1=1");
             if (!string.IsNullOrEmpty(txtSUserName.Text.Trim()))
             {
                 sb.Append(string.Format("and UserName='{0}'", txtSUserName.Text.Trim()));
             }
             if (ddlselPhase.SelectedIndex > )
             {
                 sb.Append(string.Format("and phase='{0}'", ddlselPhase.SelectedValue));
             }
             return sb.ToString();
         }

         protected void btnAdd_Click(object sender, EventArgs e)
         {
             try
             {
                 string addUserName = txtAddUserName.Text.Trim();
                 string addPwd = txtAddPwd.Text.Trim();
                 string addqq = txtAddQq.Text.Trim();
                 string addPhase = ddlAddPhase.SelectedIndex >  ? ddlAddPhase.SelectedValue : "";
                 if (!string.IsNullOrEmpty(addUserName))
                 {
                     using (con = new SqlConnection(constr))
                     {
                         con.Open();
                         string sstring1 = string.Format("insert into UserInfor(UserName,Pwd,QQ,Phase)values('{0}','{1}','{2}','{3}')", addUserName, addPwd, addqq, addPhase);
                         cmd = new SqlCommand(sstring1, con);
                         if (cmd.ExecuteNonQuery() > )
                         {
                             Response.Write("<script>alert('插入成功！');</script>");
                         }
                         BindUserInfor();
                     }
                 }
                 else
                 {
                     Response.Write("<script>alert('请输入内容');</script>");
                 }
             }
             catch (Exception)
             {
                 Response.Write("网页正在维护！");
             }
         }

         protected void btnD_Click(object sender, EventArgs e)
         {
             int UserId = txtDUId.Text.Trim() == "" ?  : Convert.ToInt32(txtDUId.Text.Trim());
             try
             {
                 using (con = new SqlConnection(constr))
                 {
                     con.Open();
                     string ssql = string.Format("select UserId from UserInfor where UserId='{0}'", UserId);
                     cmd = new SqlCommand(ssql, con);
                     read = cmd.ExecuteReader();
                     if (read.HasRows)
                     {
                         read.Dispose();
                         read.Close();
                         string sstring1 = string.Format("delete UserInfor where UserId='{0}'", UserId);
                         cmd = new SqlCommand(sstring1, con);
                         if (cmd.ExecuteNonQuery() > )
                         {
                             Response.Write("<script>alert('删除成功！');</script>");
                         }
                         BindUserInfor();
                     }
                     else
                     {
                         Response.Write("该用户不存在！");
                     }
                 }
             }
             catch (Exception ex)
             {
                 Response.Write("<script>alret('系统正在维护，请联系管理员!');</script>");
             }
         }

         protected void btnU_Click(object sender, EventArgs e)
         {
             int uId = txtUId.Text.Trim()==""?:Convert.ToInt32(txtUId.Text.Trim());
             string uUserName = txtUUserName.Text.Trim();
             try
             {
                 using (con = new SqlConnection(constr))
                 {
                     con.Open();
                     string ssql = string.Format("select UserId from UserInfor where UserId='{0}'", uId);
                     cmd = new SqlCommand(ssql, con);
                     read = cmd.ExecuteReader();
                     if (read.HasRows)
                     {
                         read.Dispose();
                         read.Close();
                         string ssql1 = string.Format("update UserInfor set UserName='{0}' where UserId='{1}'", uUserName, uId);
                         cmd = new SqlCommand(ssql1, con);
                         if (cmd.ExecuteNonQuery() > )
                         {
                             Response.Write("更新成功！");
                         }
                         BindUserInfor();
                     }
                     else
                     {
                         Response.Write("该用户不存在！");
                     }
                 }
             }
             catch (Exception)
             {
                 Response.Write("<script>alret('系统正在维护，请联系管理员!');</script>");
             }
         }
     }

另一种更新的方法，调用cmd的ExecuteScalar()执行查询，记录数，返回0或1，返回是object类型

       <div>
            <table>
                <tr>
                    <td>ID:</td>
                    <td>
                        <asp:TextBox ID="txtUuid" runat="server"></asp:TextBox>
                    </td>
                    <td>
                        <asp:TextBox ID="txtUuserName2" runat="server"></asp:TextBox>
                    </td>
                    <td>
                        <asp:Button ID="btnU2" runat="server" Text="更新" OnClick="btnU2_Click"/>
                    </td>
                </tr>
            </table>
        </div>

      protected void btnU2_Click(object sender, EventArgs e)
         {
             int Uid2 = txtUuid.Text.Trim() == "" ?  : Convert.ToInt32(txtUuid.Text.Trim());
             string uusername2 = txtUuserName2.Text.Trim();
             try
             {
                 using (con = new SqlConnection(constr))
                 {
                     con.Open();
                     string ssql = string.Format("select count(*) from UserInfor where userid='{0}'", Uid2);
                     cmd = new SqlCommand(ssql, con);
                     int icount = Convert.ToInt32(cmd.ExecuteScalar().ToString());
                     if (icount> )
                     {
                         string ssql1 = string.Format("update UserInfor set UserName='{0}' where UserId='{1}'", uusername2, Uid2);
                         cmd = new SqlCommand(ssql1,con);
                         if (cmd.ExecuteNonQuery() > )
                         {
                             Response.Write("<script>alert('数据更新成功！');</script>");
                         }
                         BindUserInfor();
                     }
                     else
                     {
                         Response.Write("该用户不存在！");
                     }
                 }
             }
             catch (Exception)
             {
                 Response.Write("<script>alret('系统正在维护，请联系管理员!');</script>");
             }
         }

二、Get传值：传一些安全系数低，Id,传类型，比较小的数据

     <div>
             <%=GetUserInfor()%>
     </div>

 public partial class UserInforManagerContext : System.Web.UI.Page
     {
         /// <summary>
         ///通过这种方式把ID传了过去 ?<%#Eval("UserId") %>,接收get传值后的id
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>

         private int _userId;//定义一个字段,只可以访问

         public int UserId
         {
             //get,set是属性，既可以访问，又可以写
             get
             {
                 try
                 {
                     _userId = Request.QueryString["Id"] == "" ?  : Convert.ToInt32(Request.QueryString["Id"].ToString());
                 }
                 catch (Exception)
                 {
                     _userId = ;
                 }
                 return _userId;
             }
             set { _userId = value; }
         }
         protected void Page_Load(object sender, EventArgs e)
         {

         }

         public string GetUserInfor()
         {
             StringBuilder sb = new StringBuilder();
             sb.Append("<table>");
             try
             {
                 if (UserId > )
                 {
                     string constr = ConfigurationManager.ConnectionStrings["sq_r"].ToString();
                     using (SqlConnection con = new SqlConnection(constr))
                     {
                         con.Open();
                         string sString = string.Format("select * from UserInfor where UserId='{0}'", UserId);
                         SqlCommand cmd = new SqlCommand(sString, con);
                         using (SqlDataReader read = cmd.ExecuteReader())
                         {
                             if (read.HasRows)
                             {
                                 if (read.Read())
                                 {
                                     sb.Append(string.Format("<tr><td>ID:</td><td>{0}</td></tr>", UserId));
                                     sb.Append(string.Format("<tr><td>用户名:</td><td>{0}</td></tr>", read["userName"].ToString()));
                                     sb.Append(string.Format("<tr><td>电话号码:</td><td>{0}</td></tr>", read["PhoneNum"].ToString()));
                                     sb.Append(string.Format("<tr><td>QQ:</td><td>{0}</td></tr>", read["QQ"].ToString()));
                                     sb.Append(string.Format("<tr><td>信息:</td><td>{0}</td></tr>", read["Message"].ToString()));
                                 }
                             }
                         }
                     }
                 }
                 else
                 {
                     sb.Append("<tr><td>未找到相关数据!</td></tr>");
                 }
             }
             catch (Exception)
             {
                 Response.Write("网站正在维护，请联系管理员!");
             }
             sb.Append("</table>");
             return sb.ToString();
         }
     }

三、批量删除:

3.1全选：

 <div>
             <table>
                 <tr>
                     <td>用户ID:</td>
                     <td>
                         <asp:TextBox ID="txtDUId" runat="server"></asp:TextBox>
                     </td>
                     <td>
                         <asp:Button ID="btnD" runat="server" Text="删除" OnClick="btnD_Click" />
                     </td>
                 </tr>
             </table>
         </div>
        <div class="dItem">
             <asp:Button ID="btnDelAll" runat="server" Text="批量删除" OnClick="btnDelAll_Click" OnClientClick="return confirm('你确定删除吗？');"/>
         </div>
        <div>
         <asp:GridView ID="GriVShow" runat="server" AutoGenerateColumns="False">
             <Columns>
                 <asp:TemplateField>
                     <HeaderTemplate>
                         <asp:CheckBox ID="chkAll" runat="server" AutoPostBack="True" OnCheckedChanged="chkAll_CheckedChanged" />
                     </HeaderTemplate>
                     <ItemTemplate>
                         <asp:CheckBox ID="chkItem" runat="server" />
                     </ItemTemplate>
                 </asp:TemplateField>
                 <asp:BoundField DataField="Userid" HeaderText="用户ID" />
                 <asp:BoundField DataField="UserName" HeaderText="用户名：" />
                 <asp:BoundField DataField="phonenum" HeaderText="电话号码" />
                 <asp:BoundField DataField="sex" HeaderText="性别" />
                 <asp:BoundField DataField="phase" HeaderText="班级" />
                 <asp:BoundField DataField="qq" HeaderText="QQ" />
                 <asp:BoundField DataField="Message" HeaderText="信息" />
                 <asp:BoundField DataField="HeadPic" HeaderText="头像" />
                 <asp:BoundField DataField="CreatedTime" HeaderText="创建时间" />
                 <asp:TemplateField HeaderText="详情">
                     <ItemTemplate>
                         <a href="UserInforManagerContext.aspx?Id=<%#Eval("UserId")%>">详情</a>
                     </ItemTemplate>
                 </asp:TemplateField>
             </Columns>
         </asp:GridView>
     </div>

     public partial class UserInforManager : System.Web.UI.Page
     {
         string constr = ConfigurationManager.ConnectionStrings["sq_r"].ToString();
         SqlConnection con = null;
         SqlCommand cmd = null;
         SqlDataReader read = null;
         protected void Page_Load(object sender, EventArgs e)
         {
             if (!(IsPostBack))
             {
                 BindUserInfor();
             }
         }
         /// <summary>
         /// 数据绑定
         /// </summary>
         public void BindUserInfor()
         {
             try
             {
                 //string strstring = "select Userid,UserName,phonenum,sex,phase,qq,Message,HeadPic,CreatedTime from UserInfor where 1=1";
                 using (con = new SqlConnection(constr))
                 {
                     con.Open();
                     cmd = new SqlCommand(GetSql(), con);
                     using (read = cmd.ExecuteReader())
                     {
                         //开始读以上sql数据,这句话一定要有，如果把它取出来的话是需要读的，但是这地方我只想它把内容赋值给gridview
                         //if (read.Read())
                         //{
                         //}
                         //但是这地方我只想它把内容赋值给gridview
                         //内容取出来之后，我希望有东西可以接收它的内容
                         GriVShow.DataSource = read;
                         GriVShow.DataBind();
                     }
                 }
             }
             catch (Exception ex)
             {
                 Response.Write("<script>alret('系统正在维护，请联系管理员!');</script>");
             }
         }

         protected void btnSel_Click(object sender, EventArgs e)
         {
             BindUserInfor();
         }
         /// <summary>
         /// 获取SQL
         /// </summary>
         /// <returns></returns>
         public string GetSql()
         {
             //string username = txtSUserName.Text.Trim();
             //string phase = ddlselPhase.SelectedValue;
             StringBuilder sb = new StringBuilder();
             sb.Append("select Userid,UserName,phonenum,sex,phase,qq,Message,HeadPic,CreatedTime from UserInfor where 1=1");
             if (!string.IsNullOrEmpty(txtSUserName.Text.Trim()))
             {
                 sb.Append(string.Format("and UserName='{0}'", txtSUserName.Text.Trim()));
             }
             if (ddlselPhase.SelectedIndex > )
             {
                 sb.Append(string.Format("and phase='{0}'", ddlselPhase.SelectedValue));
             }
             return sb.ToString();
         }

         protected void btnAdd_Click(object sender, EventArgs e)
         {
             try
             {
                 string addUserName = txtAddUserName.Text.Trim();
                 string addPwd = txtAddPwd.Text.Trim();
                 string addqq = txtAddQq.Text.Trim();
                 string addPhase = ddlAddPhase.SelectedIndex >  ? ddlAddPhase.SelectedValue : "";
                 if (!string.IsNullOrEmpty(addUserName))
                 {
                     using (con = new SqlConnection(constr))
                     {
                         con.Open();
                         string sstring1 = string.Format("insert into UserInfor(UserName,Pwd,QQ,Phase)values('{0}','{1}','{2}','{3}')", addUserName, addPwd, addqq, addPhase);
                         cmd = new SqlCommand(sstring1, con);
                         if (cmd.ExecuteNonQuery() > )
                         {
                             Response.Write("<script>alert('插入成功！');</script>");
                         }
                         BindUserInfor();
                     }
                 }
                 else
                 {
                     Response.Write("<script>alert('请输入内容');</script>");
                 }
             }
             catch (Exception)
             {
                 Response.Write("网页正在维护！");
             }
         }

         public void Del(int UserId)
         {
             try
             {
                 using (con = new SqlConnection(constr))
                 {
                     con.Open();
                     string ssql = string.Format("select UserId from UserInfor where UserId='{0}'", UserId);
                     cmd = new SqlCommand(ssql, con);
                     read = cmd.ExecuteReader();
                     if (read.HasRows)
                     {
                         read.Dispose();
                         read.Close();
                         string sstring1 = string.Format("delete UserInfor where UserId='{0}'", UserId);
                         cmd = new SqlCommand(sstring1, con);
                         if (cmd.ExecuteNonQuery() > )
                         {
                             Response.Write("<script>alert('删除成功！');</script>");
                         }

                     }
                     else
                     {
                         Response.Write("该用户不存在！");
                     }
                 }
             }
             catch (Exception ex)
             {
                 Response.Write("<script>alret('系统正在维护，请联系管理员!');</script>");
             }
         }
         protected void btnD_Click(object sender, EventArgs e)
         {
             int UserId = txtDUId.Text.Trim() == "" ?  : Convert.ToInt32(txtDUId.Text.Trim());
             Del(UserId);
             BindUserInfor();
         }

         /// <summary>
         /// 更新的第一种方法
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         protected void btnU_Click(object sender, EventArgs e)
         {
             int uId = txtUId.Text.Trim()==""?:Convert.ToInt32(txtUId.Text.Trim());
             string uUserName = txtUUserName.Text.Trim();
             try
             {
                 using (con = new SqlConnection(constr))
                 {
                     con.Open();
                     string ssql = string.Format("select UserId from UserInfor where UserId='{0}'", uId);
                     cmd = new SqlCommand(ssql, con);
                     read = cmd.ExecuteReader();
                     if (read.HasRows)
                     {
                         read.Dispose();
                         read.Close();
                         string ssql1 = string.Format("update UserInfor set UserName='{0}' where UserId='{1}'", uUserName, uId);
                         cmd = new SqlCommand(ssql1, con);
                         if (cmd.ExecuteNonQuery() > )
                         {
                             Response.Write("更新成功！");
                         }
                         BindUserInfor();
                     }
                     else
                     {
                         Response.Write("该用户不存在！");
                     }
                 }
             }
             catch (Exception)
             {
                 Response.Write("<script>alret('系统正在维护，请联系管理员!');</script>");
             }
         }

         /// <summary>
         /// 更新的第二种方法
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         protected void btnU2_Click(object sender, EventArgs e)
         {
             int Uid2 = txtUuid.Text.Trim() == "" ?  : Convert.ToInt32(txtUuid.Text.Trim());
             string uusername2 = txtUuserName2.Text.Trim();
             try
             {
                 using (con = new SqlConnection(constr))
                 {
                     con.Open();
                     string ssql = string.Format("select count(*) from UserInfor where userid='{0}'", Uid2);
                     cmd = new SqlCommand(ssql, con);
                     int icount = Convert.ToInt32(cmd.ExecuteScalar().ToString());
                     if (icount > )
                     {
                         string ssql1 = string.Format("update UserInfor set UserName='{0}' where UserId='{1}'", uusername2, Uid2);
                         cmd = new SqlCommand(ssql1, con);
                         if (cmd.ExecuteNonQuery() > )
                         {
                             Response.Write("<script>alert('数据更新成功！');</script>");
                         }
                         BindUserInfor();
                     }
                     else
                     {
                         Response.Write("该用户不存在！");
                     }
                 }
             }
             catch (Exception)
             {
                 Response.Write("<script>alret('系统正在维护，请联系管理员!');</script>");
             }
         }

         protected void chkAll_CheckedChanged(object sender, EventArgs e)
         {
             //1.当我们点击按钮时，去找chkAll它的事件源的对象把它变成checkBox
             CheckBox chkAll = sender as CheckBox;
             //2.对它的每一行进行遍历循环
             foreach (GridViewRow gvr in GriVShow.Rows)
             {
                 //2.1获得到第一行的第一列，找到每一列id等于chkitem的对象把它变成checkbox
                 CheckBox chkItem = gvr.Cells[].FindControl("chkItem") as CheckBox;
                 //2.2让它当前全选的checked属性等于下面每一行的属性，选中就为true，没选就为Fulse
                 chkItem.Checked = chkAll.Checked;
             }
         }

         protected void btnDelAll_Click(object sender, EventArgs e)
         {
             //1.对Gridview进行遍历循环
             foreach (GridViewRow gvr in GriVShow.Rows)
             {
                 //2.1获取到每行第二列的值
                 int UserId = Convert.ToInt32(gvr.Cells[].Text);
                 //2.2获取到每一行的第一列就是去找ID等于chkItem的对象把它变成checkbox
                 CheckBox chkItem=gvr.Cells[].FindControl("chkItem") as CheckBox;
                 if(chkItem.Checked)
                 {
                     Del(UserId);
                 }
             }
             BindUserInfor();
         }
     }

4.GridView-模板绑定下拉列表数据

[首先这地方一定要与数据库要绑定的字段对应]，不然像楼主一样走了一个大坑

 <asp:TemplateField HeaderText="班级">
                     <ItemTemplate>
                         <asp:DropDownList ID="ddlgvPhase" runat="server" ToolTip='<%#Eval("phase")%>'>
                             <asp:ListItem>---请选择---</asp:ListItem>
                             <asp:ListItem>.NET高级班01期</asp:ListItem>
                             <asp:ListItem>.NET高级班02期</asp:ListItem>
                             <asp:ListItem>.NET讲师</asp:ListItem>
                             <asp:ListItem>.NET网站开发01期</asp:ListItem>
                             <asp:ListItem>.NET网站开发02期</asp:ListItem>
                             <asp:ListItem>.NET网站开发03期</asp:ListItem>
                             <asp:ListItem>.NET网站开发04期</asp:ListItem>
                             <asp:ListItem>.NET网站开发05期</asp:ListItem>
                             <asp:ListItem>.NET网站开发06期</asp:ListItem>
                             <asp:ListItem>.NET网站开发07期</asp:ListItem>
                             <asp:ListItem>.NET网站开发08期</asp:ListItem>
                             <asp:ListItem>.NET网站开发09期</asp:ListItem>
                             <asp:ListItem>.NET网站开发10期</asp:ListItem>
                             <asp:ListItem>.NET网站开发11期</asp:ListItem>
                             <asp:ListItem>.NET网站开发12期</asp:ListItem>
                             <asp:ListItem>.NET网站开发13期</asp:ListItem>
                             <asp:ListItem>.NET网站开发14期</asp:ListItem>
                             <asp:ListItem>ps设计01期</asp:ListItem>
                             <asp:ListItem>ps设计03期</asp:ListItem>
                             <asp:ListItem>网页前端01期</asp:ListItem>
                         </asp:DropDownList>
                     </ItemTemplate>
                 </asp:TemplateField>

这时候，我们需要调用gridView的RowDataBound事件，当我们打开浏览器，gridView加载从第一行到第二行的逐行加载，加载的时候就执行这个方法，为什么要调用这个方法呢？表示对gridView进行一个遍历

如何找到这个事件呢？GridView的属性-事件里就有，找到双击就好

  protected void GriVShow_RowDataBound(object sender, GridViewRowEventArgs e)
         {
             //判断当前行是不是数据行
             //获取到某行输入的数据把它变成UserInfor类型,对象才能调用它的属性方法
             //e.Row.DataItem当前行的数据集
             //找打当前行的班级
             if (e.Row.RowType == DataControlRowType.DataRow)
             {
                 DropDownList ddlPhase = e.Row.FindControl("ddlgvPhase") as DropDownList;
                 string phase = ddlPhase.ToolTip;
                 if (!string.IsNullOrEmpty(phase))
                 {
                     //清空列表里所有的项
                     ddlPhase.ClearSelection();
                     ddlPhase.Items.FindByValue(phase).Selected = true;
                 }
             }
         }

5.批量更新:

userinfor这个常用的东西，我们直接封装成一个方法，直接调用该方法就好

 SqlConnection con = null;
         SqlCommand cmd = null;
         SqlDataReader read = null;
         string constr = ConfigurationManager.ConnectionStrings["sq_r"].ToString();
         protected void Page_Load(object sender, EventArgs e)
         {
             if (!(IsPostBack))//页面第一次加载
             {
                 BindUserInfor();
             }
         }

         public void BindUserInfor()
         {
             try
             {
                 using (con = new SqlConnection(constr))
                 {
                     // where 1=1 order by UserId desc
                     con.Open();
                     string sSql = "select  top 100 Userid,UserName,Pwd,phonenum,phase,qq,CreatedTime from UserInfor where 1=1 order by UserId desc";
                     cmd = new SqlCommand(sSql, con);
                     using (read = cmd.ExecuteReader())
                     {
                         GriVShow.DataSource = read;
                         GriVShow.DataBind();
                     }
                 }
             }
             catch (Exception)
             {
                 Response.Write("网页正在维护!");
             }
         }

前台实例的代码都在这：

 <form id="form1" runat="server">
        <div class="dItem">
            <table>
                <tr>
                    <td>
                        <asp:Button ID="btnDelAll" runat="server" Text="批量删除" OnClick="btnDelAll_Click" OnClientClick="return confirm('你确定删除吗？');"/>
                    </td>
                    <td>
                        <asp:Button ID="btnUpAll" runat="server" Text="批量修改" OnClick="btnUpAll_Click" />
                    </td>
                    <td>
                        <asp:Button ID="btnAddBottom" runat="server" Text="添加" OnClick="btnAddBottom_Click" />
                    </td>
                </tr>
            </table>
         </div>
        <div>
         <asp:GridView ID="GriVShow" runat="server" AutoGenerateColumns="False" OnRowDataBound="GriVShow_RowDataBound">
             <Columns>
                 <asp:TemplateField>
                     <HeaderTemplate>
                         <asp:CheckBox ID="chkAll" runat="server" AutoPostBack="True" OnCheckedChanged="chkAll_CheckedChanged" />
                     </HeaderTemplate>
                     <ItemTemplate>
                         <asp:CheckBox ID="chkItem" runat="server" />
                     </ItemTemplate>
                 </asp:TemplateField>
                 <asp:BoundField DataField="Userid" HeaderText="ID" />
                 <asp:BoundField DataField="UserName" HeaderText="用户名：" />
                 <asp:BoundField DataField="phonenum" HeaderText="电话号码" />
                 <asp:BoundField DataField="qq" HeaderText="QQ" />
                 <asp:BoundField DataField="phase" HeaderText="班级" />
                 <asp:BoundField DataField="CreatedTime" HeaderText="创建时间" />
                 <asp:TemplateField HeaderText="用户名">
                     <ItemTemplate>
                         <asp:TextBox ID="txtgvUserName" runat="server" Text='<%#Eval("UserName")%>'></asp:TextBox>
                     </ItemTemplate>
                 </asp:TemplateField>
                 <asp:TemplateField HeaderText="密码">
                     <ItemTemplate>
                         <asp:TextBox ID="txtgvPwd" runat="server" Text='<%#Eval("Pwd")%>'></asp:TextBox>
                     </ItemTemplate>
                 </asp:TemplateField>
                 <asp:TemplateField HeaderText="QQ">
                     <ItemTemplate>
                         <asp:TextBox ID="txtgvQq" runat="server" Text='<%#Eval("QQ")%>'></asp:TextBox>
                     </ItemTemplate>
                 </asp:TemplateField>
                 <asp:TemplateField HeaderText="班级">
                     <ItemTemplate>
                         <asp:DropDownList ID="ddlgvPhase" runat="server" ToolTip='<%#Eval("phase")%>'>
                             <asp:ListItem>---请选择---</asp:ListItem>
                             <asp:ListItem>.NET高级班01期</asp:ListItem>
                             <asp:ListItem>.NET高级班02期</asp:ListItem>
                             <asp:ListItem>.NET讲师</asp:ListItem>
                             <asp:ListItem>.NET网站开发01期</asp:ListItem>
                             <asp:ListItem>.NET网站开发02期</asp:ListItem>
                             <asp:ListItem>.NET网站开发03期</asp:ListItem>
                             <asp:ListItem>.NET网站开发04期</asp:ListItem>
                             <asp:ListItem>.NET网站开发05期</asp:ListItem>
                             <asp:ListItem>.NET网站开发06期</asp:ListItem>
                             <asp:ListItem>.NET网站开发07期</asp:ListItem>
                             <asp:ListItem>.NET网站开发08期</asp:ListItem>
                             <asp:ListItem>.NET网站开发09期</asp:ListItem>
                             <asp:ListItem>.NET网站开发10期</asp:ListItem>
                             <asp:ListItem>.NET网站开发11期</asp:ListItem>
                             <asp:ListItem>.NET网站开发12期</asp:ListItem>
                             <asp:ListItem>.NET网站开发13期</asp:ListItem>
                             <asp:ListItem>.NET网站开发14期</asp:ListItem>
                             <asp:ListItem>ps设计01期</asp:ListItem>
                             <asp:ListItem>ps设计03期</asp:ListItem>
                             <asp:ListItem>网页前端01期</asp:ListItem>
                         </asp:DropDownList>
                     </ItemTemplate>
                 </asp:TemplateField>
                 <asp:TemplateField HeaderText="详情">
                     <ItemTemplate>
                         <a href="UserInforManagerContext.aspx?Id=<%#Eval("UserId")%>">详情</a>
                     </ItemTemplate>
                 </asp:TemplateField>
             </Columns>
         </asp:GridView>
     </div>
     </form>

封装了一个更新的方法，直接调用该方法即可

 public void UpUser(int userId,string username,string pwd,string qq,string phase)
         {
             try
             {
                 using (con = new SqlConnection(constr))
                 {
                     con.Open();
                     string ssql= string.Format("update UserInfor set UserName='{0}',Pwd='{1}',QQ='{2}',Phase='{3}' where UserId='{4}'", username, pwd, qq, phase, userId);
                     cmd = new SqlCommand(ssql, con);
                         if (cmd.ExecuteNonQuery() > )
                         {
                             Response.Write("<script>alert('数据更新成功！');</script>");
                         }
                 }
             }
             catch (Exception)
             {
                 Response.Write("网页正在维护!");
             }

         }
         /// <summary>
         /// 批量更新
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         protected void btnUpAll_Click(object sender, EventArgs e)
         {
             //遍历gridView
             foreach (GridViewRow gvr in GriVShow.Rows)
             {
                 int UserId = Convert.ToInt32(gvr.Cells[].Text);
                 CheckBox chkItem = gvr.Cells[].FindControl("chkItem") as CheckBox;
                 if (chkItem.Checked)
                 {
                     TextBox txtusername = gvr.Cells[].FindControl("txtgvUserName") as TextBox;
                     TextBox txtpwd = gvr.Cells[].FindControl("txtgvPwd") as TextBox;
                     TextBox txtqq = gvr.Cells[].FindControl("txtgvQq") as TextBox;
                     DropDownList ddlphase = gvr.Cells[].FindControl("ddlgvPhase") as DropDownList;
                     UpUser(UserId,txtusername.Text,txtpwd.Text,txtqq.Text,ddlphase.SelectedValue);
                 }
             }
             BindUserInfor();
         }

5.添加的后台代码：双击添加按钮进入后台事件

 protected void btnAdd_Click(object sender, EventArgs e)
         {
             try
             {
                 using (con = new SqlConnection(constr))
                 {
                     con.Open();
                     string ssql = string.Format("insert into UserInfor (Phase,CreatedTime) values('{0}','{1}')", "网页前端01期", DateTime.Now.ToString());
                     cmd = new SqlCommand(ssql, con);
                     cmd.ExecuteNonQuery();
                 }
                 BindUserInfor();
             }
             catch (Exception)
             {
                 Response.Write("网页正在维护!");
             }
         }