合并实现DataGrid多表头 （转自：http://singlepine.cnblogs.com/articles/282990.html）

< HTML >
     < HEAD >
         < title > MergeHeader </ title >
         < meta  name ="GENERATOR"  Content ="Microsoft Visual Studio .NET 7.1" >
         < meta  name ="CODE_LANGUAGE"  Content ="C#" >
         < meta  name ="vs_defaultClientScript"  content ="JavaScript" >
         < meta  name ="vs_targetSchema"  content ="http://schemas.microsoft.com/intellisense/ie5" >
     </ HEAD >
     < body  MS_POSITIONING ="GridLayout" >
         < form  id ="Form1"  method ="post"  runat ="server" >
             < asp:datagrid  id ="DataGrid1"  style ="Z-INDEX: 101; LEFT: 8px; POSITION: absolute; TOP: 8px"  runat ="server"
                BorderColor ="Tan"  BorderWidth ="1px"  BackColor ="LightGoldenrodYellow"  CellPadding ="1"  ForeColor ="Black"
                CellSpacing ="1" >
                 < FooterStyle  BackColor ="Tan" ></ FooterStyle >
                 < SelectedItemStyle  ForeColor ="GhostWhite"  BackColor ="DarkSlateBlue" ></ SelectedItemStyle >
                 < AlternatingItemStyle  BackColor ="PaleGoldenrod" ></ AlternatingItemStyle >
                 < HeaderStyle  Font-Bold ="True"  BackColor ="Tan" ></ HeaderStyle >
                 < PagerStyle  HorizontalAlign ="Center"  ForeColor ="DarkSlateBlue"  BackColor ="PaleGoldenrod" ></ PagerStyle >
             </ asp:datagrid >
         </ form >
     </ body >
</ HTML >

public   class  MergeHeader : System.Web.UI.Page
     {
        private DataGrid m_dgDatagridToDecorate = null;
        private ArrayList m_arrHeaderCells = null;
        protected System.Web.UI.WebControls.DataGrid DataGrid1;        
        private Hashtable m_htblRowspanIndex = new Hashtable();

        private void Page_Load(object sender, System.EventArgs e)
        {
            if(!this.IsPostBack)
            {
                MergeGrid();
            }
        }

        AddMergeHeader#region AddMergeHeader
        private void AddMergeHeader(ArrayList arrHeaderCells)
        {
            m_arrHeaderCells =arrHeaderCells;
        }
        #endregion

        property#region property
        private DataGrid DatagridToDecorate
        {
            get
            {
                return m_dgDatagridToDecorate;
            }
            set
            {
                if(null != m_dgDatagridToDecorate)
                {
                    m_dgDatagridToDecorate.ItemCreated -= new DataGridItemEventHandler(DatagridToDecorate_ItemCreated);
                }
                m_dgDatagridToDecorate = value;    
                m_dgDatagridToDecorate.ItemCreated += new DataGridItemEventHandler(DatagridToDecorate_ItemCreated);
            }
        }
        #endregion        

        DatagridToDecorate_ItemCreated#region DatagridToDecorate_ItemCreated
        private void DatagridToDecorate_ItemCreated(object sender, System.Web.UI.WebControls.DataGridItemEventArgs e)
        {
            //*** Examine if the item created is the header item
            ListItemType lit = e.Item.ItemType;
            if(ListItemType.Header == lit)
            {
                //*** Redirect the default header rendering method to our own method
                e.Item.SetRenderMethodDelegate(new RenderMethod(NewRenderMethod));                
            }
        }
        #endregion        

        NewRenderMethod#region NewRenderMethod
        private void NewRenderMethod(HtmlTextWriter writer, Control ctl)
        {            
            int iCurrIndex = 0;
            for(int i=0; i<m_arrHeaderCells.Count; i++)
            {
                TableCell item = (TableCell)m_arrHeaderCells[i];                
                if(item.ColumnSpan > 1)
                {
                    iCurrIndex += item.ColumnSpan-1;
                }
                if(item.RowSpan > 1)
                {
                    m_htblRowspanIndex.Add(iCurrIndex + i, iCurrIndex + i);
                }
                item.RenderControl(writer);
            }
            writer.WriteEndTag("TR");            
            //*** Add the style attributes that was defined in design time
            //      to our second row so they both will have the same appearance
            m_dgDatagridToDecorate.HeaderStyle.AddAttributesToRender(writer);            
            //*** Insert the second row
            writer.RenderBeginTag("TR");
            //*** Render all the cells that was defined in design time, except the last one
            //      because we already rendered it above
            for(int i=0; i< ctl.Controls.Count; i++)
            {
                if((null == m_htblRowspanIndex[i]))
                {
                    ctl.Controls[i].RenderControl(writer);
                }
            }            
            //*** We don't need to write the </TR> close tag because the writer will do that for us
            //      and so we're done :)
        }

        #endregion

        GetData#region GetData
        private DataTable GetData()
        {
            DataTable dt;
            dt = new DataTable();

            dt.Columns.Add("Code");
            dt.Columns.Add("FName");
            dt.Columns.Add("MName");
            dt.Columns.Add("LName");
            dt.Columns.Add("Age");
            dt.Columns.Add("Elementary");
            dt.Columns.Add("Junior");
            dt.Columns.Add("High");
            dt.Columns.Add("Religion");

            for(int i=1; i <= 12; i++)
            {
                DataRow dr = dt.NewRow();

                dr["Code"] = "Code" + i.ToString();
                dr["FName"] = "FName" + i.ToString();
                dr["MName"] = "MName" + i.ToString();
                dr["LName"] = "LName" + i.ToString();
                dr["Age"] = "Age" + i.ToString();
                dr["Elementary"] = "Elementary" + i.ToString();
                dr["Junior"] = "Junior" + i.ToString();
                dr["High"] = "High" + i.ToString();
                dr["Religion"] = "Religion" + i.ToString();

                dt.Rows.Add(dr);
            }
            return dt;
        }
        #endregion

        MergeGrid#region MergeGrid
        private void MergeGrid()
        {
            TableCell cell = null;

            DatagridToDecorate = DataGrid1;
            ArrayList header = new ArrayList();                                

            cell = new TableCell();
            cell.Text = "Name";
            cell.RowSpan = 2;
            cell.HorizontalAlign = HorizontalAlign.Center;
            header.Add(cell);

            cell = new TableCell();
            cell.Text = "Name";
            cell.ColumnSpan = 3;            
            cell.HorizontalAlign = HorizontalAlign.Center;
            header.Add(cell);

            cell = new TableCell();
            cell.Text = "Age";
            cell.RowSpan = 2;
            cell.HorizontalAlign = HorizontalAlign.Center;
            header.Add(cell);

            cell = new TableCell();
            cell.Text = "School";
            cell.ColumnSpan = 3;
            cell.HorizontalAlign = HorizontalAlign.Center;
            header.Add(cell);

            cell = new TableCell();
            cell.Text = "Religion";
            cell.RowSpan = 2;
            cell.HorizontalAlign = HorizontalAlign.Center;
            header.Add(cell);

            AddMergeHeader(header);

            DataGrid1.DataSource = GetData();
            DataGrid1.DataBind();
        }
        #endregion        

        Web Form Designer generated code#region Web Form Designer generated code
        override protected void OnInit(EventArgs e)
        {
            //
            // CODEGEN: This call is required by the ASP.NET Web Form Designer.
            //
            InitializeComponent();
            base.OnInit(e);
        }
        
        /**//// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {    
            this.Load += new System.EventHandler(this.Page_Load);

        }
        #endregion        
    }