asp.net使用控件datagrid实现表头单元格合并

合并的要点:

1.datagid的单元格合并原理是table中tr,td的布局实现;

2.合并的时机实在其datagridcreate事件中实现;

3.认识一个对象TableCellCollection,它是由TableCell组成的集合,TableCell可以看成一个标题.

实现下面的效果;

前台只有一个空DataGrid,后台源码如下:

 private DataTable dt = null;
         protected void Page_Load(object sender, EventArgs e)
         {
             //数据源
             dt = new DataTable();
             dt.Columns.Add("姓名");
             dt.Columns.Add("年龄");
             dt.Columns.Add("住址");
             dt.Columns.Add("公司");
             dt.Columns.Add("邮件");
             dt.Columns.Add("电话");

             //绑定数据源
             mydg.DataSource = dt;
             mydg.DataBind();

         }

         protected void mydg_ItemCreated(object sender, DataGridItemEventArgs e)
         {
             if (e.Item.ItemType == ListItemType.Header)
             {
                 List<CellRule> ils = new List<CellRule>();

                 TableCellCollection tcc = e.Item.Cells;
                 tcc.Add(new TableCell());
                 tcc[].Text = dt.Columns[].ColumnName;
                 tcc[].Attributes.Add("rowspan", "");
                 tcc.Add(new TableCell());
                 tcc[].Text = dt.Columns[].ColumnName;
                 tcc[].Attributes.Add("rowspan", "");
                 tcc.Add(new TableCell());
                 tcc[].Attributes.Add("colspan", "");
                 tcc[].Text = "详细信息</th></tr><tr>";
                 tcc[].HorizontalAlign = HorizontalAlign.Center;

                 tcc.Add(new TableCell());
                 tcc[].Text = dt.Columns[].ColumnName;
                 tcc.Add(new TableCell());
                 tcc[].Text = dt.Columns[].ColumnName;
                 tcc.Add(new TableCell());
                 tcc[].Text = dt.Columns[].ColumnName;
                 tcc.Add(new TableCell());
                 tcc[].Text = dt.Columns[].ColumnName;

                 //ils.Add(new CellRule(2, 4, "详细信息"));
                 //OganizeTcc(e.Item.Cells, ils, dt);
             }
         }

再将合并表头单元格封装成通用的方法:

优化后的代码如下:

 private DataTable dt = null;
         protected void Page_Load(object sender, EventArgs e)
         {
             //数据源
             dt = new DataTable();
             dt.Columns.Add("姓名");
             dt.Columns.Add("年龄");
             dt.Columns.Add("住址");
             dt.Columns.Add("公司");
             dt.Columns.Add("邮件");
             dt.Columns.Add("电话");

             //绑定数据源
             mydg.DataSource = dt;
             mydg.DataBind();

         }

         protected void mydg_ItemCreated(object sender, DataGridItemEventArgs e)
         {
             if (e.Item.ItemType == ListItemType.Header)
             {
                 List<CellRule> ils = new List<CellRule>();

                 //TableCellCollection tcc = e.Item.Cells;
                 //tcc.Add(new TableCell());
                 //tcc[0].Text = dt.Columns[0].ColumnName;
                 //tcc[0].Attributes.Add("rowspan", "2");
                 //tcc.Add(new TableCell());
                 //tcc[1].Text = dt.Columns[1].ColumnName;
                 //tcc[1].Attributes.Add("rowspan", "2");
                 //tcc.Add(new TableCell());
                 //tcc[2].Attributes.Add("colspan", "4");
                 //tcc[2].Text = "详细信息</th></tr><tr>";
                 //tcc[2].HorizontalAlign = HorizontalAlign.Center;

                 //tcc.Add(new TableCell());
                 //tcc[3].Text = dt.Columns[2].ColumnName;
                 //tcc.Add(new TableCell());
                 //tcc[4].Text = dt.Columns[3].ColumnName;
                 //tcc.Add(new TableCell());
                 //tcc[5].Text = dt.Columns[4].ColumnName;
                 //tcc.Add(new TableCell());
                 //tcc[6].Text = dt.Columns[5].ColumnName;

                 ils.Add(new CellRule(, , "详细信息"));
                 OganizeTcc(e.Item.Cells, ils, dt);
             }
         }

         private void OganizeTcc(TableCellCollection tcc, List<CellRule> ils, DataTable dt)
         {
             tcc.Clear();
             ils = ils.OrderBy(p => p.iStart).ToList();
             List<string> secHeaders = new List<string>();
             //第一行
             for (int i = , j = ; j < dt.Columns.Count;)
             {
                 if (i >= ils.Count || ils[i].iStart != j)
                 {
                     tcc.Add(new TableCell());
                     tcc[tcc.Count - ].Text = dt.Columns[j].ColumnName;
                     tcc[tcc.Count - ].Attributes.Add("rowspan", "");
                     j++;
                     if (j == dt.Columns.Count)
                         tcc[tcc.Count - ].Text = tcc[tcc.Count - ].Text + "</th></tr><tr>";
                 }
                 else
                 {
                     for (int iSec = ; iSec < ils[i].iCount; iSec++)
                     {
                         secHeaders.Add(dt.Columns[j + iSec].ColumnName);
                     }
                     tcc.Add(new TableCell());
                     tcc[tcc.Count-].Text = ils[i].strHeaderText;
                     tcc[tcc.Count - ].Attributes.Add("colspan", ils[i].iCount.ToString());
                     tcc[tcc.Count - ].HorizontalAlign = HorizontalAlign.Center;
                     j = j + ils[i].iCount;
                     i++;
                     if(j == dt.Columns.Count)
                         tcc[tcc.Count-].Text = tcc[tcc.Count-].Text+"</th></tr><tr>";
                 }

             }
             //第二行
             foreach (string str in secHeaders)
             {
                 tcc.Add(new TableCell());
                 tcc[tcc.Count - ].Text = str;
             }
         }

设定合并规则的实体类:

 public class CellRule
     {
         public int iStart { get; set; }
         public int iCount { get; set; }
         public string strHeaderText { get; set; }
         public CellRule(int iStart, int iCount, string strHeaderText)
         {
             this.iStart = iStart;
             this.iCount = iCount;
             this.strHeaderText = strHeaderText;
         }
     }

现在只有一阶转二阶的方法,如果在搞成N阶通用的方法,我是暂时想不到了.就这样.