绑定多个ddl

添加材料，需要绑定材料类型、设备名称、省份和所属终端客户等信息，前台页面如下：

前台.aspx

<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">

<p>
        BarCode:<asp:TextBox ID="txt_barcode" runat="server"></asp:TextBox>
    </p>
    <p>
        MaterialType:<asp:DropDownList ID="ddlmaterialtype" runat="server" Height="16px"
            Width="125px" AutoPostBack="True">
        </asp:DropDownList>
    </p>
    <p>
        TerminalName:<asp:DropDownList ID="ddlTerminal" runat="server" Height="16px"
            Width="126px" AutoPostBack="True" >
        </asp:DropDownList>
    </p>
    <p>
        Provinces:<asp:DropDownList ID="ddlProvince" runat="server" Height="16px"
            Width="111px">
        </asp:DropDownList>
  
    </p>
    <p>
   DeviceName:<asp:DropDownList ID="ddlDevice" runat="server"
            Height="16px" Width="125px">
        </asp:DropDownList>
    </p>
    <p>
        UseTime:
        <asp:TextBox ID="tb_usetime" runat="server"></asp:TextBox>
    </p>
    <p>
        Status:<asp:RadioButtonList ID="rbStatus" runat="server" AutoPostBack="True"
            RepeatDirection="Horizontal">
            <asp:ListItem Selected="True" Value="0">sended</asp:ListItem>
            <asp:ListItem Value="1">inBox</asp:ListItem>
            <asp:ListItem Value="2">Used</asp:ListItem>
        </asp:RadioButtonList>
    </p>
    <p>
        <asp:Button ID="btnOk" runat="server" onclick="btnOk_Click" Text="comfirm" />
&nbsp;&nbsp;
        <asp:Button ID="btncancel" runat="server" onclick="btncancel_Click"
            Text="cancel" />
    </p>

</asp:Content>

后台aspx.cs：

private SqlConnection conn;
        private SqlCommand cmd;
        private const string connStr = "Data Source=SZXY1ZWX2166591\\SQLEXPRESS;Initial Catalog=DbDevice;Integrated Security=True";

protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                this.tb_usetime.Text = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss");

BindMaterialType();
                BindTerminal();
            }
        }

void BindTerminal()
         {
             string terminalsql = "select m.TerminalID,m.TerminalName from Tbl_Terminal m";
             DataTable dt = GetTable(terminalsql);
             if (dt != null && dt.Rows.Count > 0)
             {
                 this.ddlTerminal.DataSource = dt;
                 this.ddlTerminal.DataTextField = "TerminalName";
                 this.ddlTerminal.DataValueField = "TerminalID";
                 this.ddlTerminal.DataBind();
             }
         }
        void BindMaterialType()
        {
            string sql = "select t.TypeId,t.TypeName from Tbl_ComsumerMaterialType t";
            DataTable dt=  GetTable(sql);
            if (dt != null && dt.Rows.Count > 0)
            {
                this.ddlmaterialtype.DataSource = dt;
                this.ddlmaterialtype.DataTextField = "TypeName";
                this.ddlmaterialtype.DataValueField = "TypeId";
                this.ddlmaterialtype.DataBind();
            }
        }

#region 数据库操作
   /// <summary>  
        /// 打链接   
        /// </summary>    
        ///<returns></returns> 
        private SqlConnection GetConn()
        {         
            if (conn == null)
                conn = new SqlConnection(connStr); 
            if (conn.State == ConnectionState.Closed)
                conn.Open();        
            else if (conn.State == ConnectionState.Broken)     
            {          
                conn.Close();       
                conn.Open();       
            }            return conn; 
        } 
                 /// <summary>   
                  /// 执行增删改查操作
                  /// </summary>  
                  /// <param name="sql"></param> 
                 /// <returns></returns> 
                 private int ExecuteNonQuery(string sql)   
                 {         
                     try       
                     {            
                         cmd = new SqlCommand(sql, GetConn());     
                         return cmd.ExecuteNonQuery();      
                     }       
                     catch     
                     {       
                         return 0; 
                     }        
                     finally    
                     {        
                         conn.Close();  
                     }   
                 }      
        /// <summary>   
        /// 读数据
         /// </summary>  
         /// <param name="sql"></param> 
         /// <returns></returns>  
        private SqlDataReader ExecuteReader(string sql)  
       {       
            try  
            {          
                cmd = new SqlCommand(sql, GetConn());   
                return cmd.ExecuteReader();      
            }        
            catch        
            {           
                return null; 
            }         
            finally     
            {       
                conn.Close();   
            }   
        }      
       
        /// <summary>    
         /// 该表数据 
        /// </summary> 
        /// <param name="sql"></param>   
         /// <returns></returns>
         private DataTable GetTable(string sql) 
         {         
         try         
         {          
         SqlDataAdapter da = new SqlDataAdapter(sql, GetConn());
             DataSet ds = new DataSet();      
             da.Fill(ds);             
             return ds.Tables[0];    
         }         
         catch        
         {           
             return null;   
         }         
         finally      
         {        
             conn.Close();  
         }     
         }    
        #endregion

protected void btncancel_Click(object sender, EventArgs e)
         {

}

protected void btnOk_Click(object sender, EventArgs e)
         {
             string serialNumber = getdate() + getRandom().ToString();

string status = this.rbStatus.SelectedValue;
             string terminal = this.ddlTerminal.SelectedItem.Value;
             string materialType = this.ddlmaterialtype.SelectedValue;
         }

private int getRandom()
         {
             Random rad = new Random();//实例化随机数产器rad；

int value = rad.Next(1000, 10000);//

return value;
         }
         private string getdate()
         {
             string date = DateTime.Now.ToString("yyyyMMddHHmmss");
             return date;
         }