HeaderTemplate Property

TemplateColumn.HeaderTemplate Property

Gets or sets the template for displaying the heading section of the TemplateColumn.

[Visual Basic]
Public Overridable Property HeaderTemplate As ITemplate
[C#]
public virtual ITemplate HeaderTemplate {get; set;}
[C++]
public: __property virtual ITemplate* get_HeaderTemplate();
public: __property virtual void set_HeaderTemplate(ITemplate*);
[JScript]
public function get HeaderTemplate() : ITemplate;
public function set HeaderTemplate(ITemplate);

Property Value

A System.Web.UI.ITemplate implemented object that contains the template for displaying the heading section of the TemplateColumn. The default value is a null reference (Nothing in Visual Basic), which indicates that this property is not set.

Remarks

Use the HeaderTemplate property to control the appearance of the heading section in the TemplateColumn. The appearance is specified by creating a template that defines how the item is rendered in the column. To specify a template for the item selected for editing, first place opening and closing <HeaderTemplate> tags between the opening and closing tags of the TemplateColumn element. You can then list the content that controls the appearance of the item between the opening and closing <HeaderTemplate> tags. The content can be as simple as plain text, or more complex by embedding other controls in the template.

Example

[Visual Basic, C#] The following example demonstrates how to use the HeaderTemplate property to control the appearance of the heading section in the TemplateColumn.

[Visual Basic] 

<%@ Page Language="VB" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>

<html>
   <script runat="server">

      Private Store As DataTable = New DataTable()
      Private StoreView As DataView  

      Sub Page_Load(sender As Object, e As EventArgs) 
     
         If IsNothing(Session("StoreData")) Then 
         
            Dim dr As DataRow
            Dim i As Integer
 
            Store = New DataTable()      

            Store.Columns.Add(New DataColumn("Tax", GetType(String)))
            Store.Columns.Add(New DataColumn("Item", GetType(String)))
            Store.Columns.Add(New DataColumn("Price", GetType(String)))

            Session("StoreData") = Store
            
            ' Create sample data.
            For i = 1 to 4 
    
               dr = Store.NewRow()

               dr(0) = "0.0%"
               dr(1) = "Item " & i.ToString()
               dr(2) = (1.23 * (i + 1)).ToString()
 
               Store.Rows.Add(dr)

            Next i       

         Else
            Store = Session("StoreData")

         End If

         StoreView = New DataView(Store)
         StoreView.Sort="Item"

         If Not IsPostBack Then                    
            BindGrid()
         End If
                   
      End Sub

      Sub MyDataGrid_Edit(sender As Object, e As DataGridCommandEventArgs) 
      
         MyDataGrid.EditItemIndex = e.Item.ItemIndex
         BindGrid()

      End Sub

      Sub MyDataGrid_Cancel(sender As Object, e As DataGridCommandEventArgs) 
      
         MyDataGrid.EditItemIndex = -1
         BindGrid()

      End Sub

      Sub MyDataGrid_Update(sender As Object, e As DataGridCommandEventArgs) 
      
         ' Get the text box that contains the price to edit. 
         ' For bound columns the edited value is stored in a text box.
         ' The text box is the first control in the Controls collection.
         Dim priceText As TextBox = e.Item.Cells(3).Controls(0)

         ' Get the check box that indicates whether to include tax from the 
         ' TemplateColumn. Notice that in this case, the check box control is
         ' second control in the Controls collection.
         Dim taxCheck As CheckBox = e.Item.Cells(2).Controls(1)

         Dim item As String = e.Item.Cells(1).Text
         Dim price As String = priceText.Text
       
         Dim dr As DataRow

         ' With a database, use an update command.  Since the data source is 
         ' an in-memory DataTable, delete the old row and replace it with a new one.

         ' Remove old entry.
         StoreView.RowFilter = "Item='" & item & "'"
         If StoreView.Count > 0 Then
            StoreView.Delete(0)
         End If
         StoreView.RowFilter = ""
 
         ' Add new entry.
         dr = Store.NewRow()

         If taxCheck.Checked Then
            dr(0) = "8.6%"
         Else 
            dr(0) = "0.0%"
         End If
         dr(1) = item
         dr(2) = price
         Store.Rows.Add(dr)

         MyDataGrid.EditItemIndex = -1
         BindGrid()

      End Sub

      Sub BindGrid() 
      
         MyDataGrid.DataSource = StoreView
         MyDataGrid.DataBind()
      
      End Sub

   </script>

<body>

   <form runat="server">

      <h3>TemplateColumn Example</h3>

      <asp:DataGrid id="MyDataGrid" runat="server"
           BorderColor="black"
           CellPadding="2"        
           OnEditCommand="MyDataGrid_Edit"
           OnCancelCommand="MyDataGrid_Cancel"
           OnUpdateCommand="MyDataGrid_Update"
           ShowFooter="True"
           AutoGenerateColumns="false">

         <Columns>

            <asp:EditCommandColumn
                 EditText="Edit"
                 CancelText="Cancel"
                 UpdateText="Update"
                 ItemStyle-Wrap="false"
                 HeaderText="Edit Controls"/>

            <asp:BoundColumn HeaderText="Description" 
                 ReadOnly="true" 
                 DataField="Item"/>

            <asp:TemplateColumn>

               <HeaderTemplate>
                  <b> Tax </b>
               </HeaderTemplate>

               <ItemTemplate>
                  <asp:Label
                       Text='<%# DataBinder.Eval(Container.DataItem, "Tax") %>'
                       runat="server"/>
               </ItemTemplate>

               <EditItemTemplate>

                  <asp:CheckBox
                       Text="Taxable" 
                       runat="server"/>

               </EditItemTemplate>

               <FooterTemplate>
                  <asp:HyperLink id="HyperLink1"
                       Text="Microsoft"
                       NavigateUrl="http://www.microsoft.com"
                       runat="server"/>
               </FooterTemplate>

            </asp:TemplateColumn>

            <asp:BoundColumn HeaderText="Price" 
                 DataField="Price"/>

         </Columns>

      </asp:DataGrid>

   </form>

</body>
</html>


[C#] 

<%@ Page Language="C#" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>

<html>
   <script runat="server">

      DataTable Store = new DataTable();
      DataView StoreView;  

      void Page_Load(Object sender, EventArgs e) 
      {
         if(Session["StoreData"] == null)
         {
            DataRow dr;
 
            Store = new DataTable();      

            Store.Columns.Add(new DataColumn("Tax", typeof(String)));
            Store.Columns.Add(new DataColumn("Item", typeof(String)));
            Store.Columns.Add(new DataColumn("Price", typeof(String)));

            Session["StoreData"] = Store;
            
            // Create sample data.
            for (int i = 1; i <= 4; i++) 
            {
               dr = Store.NewRow();

               dr[0] = "0.0%";
               dr[1] = "Item " + i.ToString();
               dr[2] = (1.23 * (i + 1)).ToString();
 
               Store.Rows.Add(dr);
            }       

         }
         else
            Store = (DataTable)Session["StoreData"];

         StoreView = new DataView(Store);
         StoreView.Sort="Item";

         if(!IsPostBack)                    
            BindGrid();
                   
      }

      void MyDataGrid_Edit(Object sender, DataGridCommandEventArgs e) 
      {
         MyDataGrid.EditItemIndex = e.Item.ItemIndex;
         BindGrid();
      }

      void MyDataGrid_Cancel(Object sender, DataGridCommandEventArgs e) 
      {
         MyDataGrid.EditItemIndex = -1;
         BindGrid();
      }

      void MyDataGrid_Update(Object sender, DataGridCommandEventArgs e) 
      {
         // Get the text box that contains the price to edit. 
         // For bound columns the edited value is stored in a text box.
         // The text box is the first control in the Controls collection.
         TextBox priceText = (TextBox)e.Item.Cells[3].Controls[0];

         // Get the check box that indicates whether to include tax from the 
         // TemplateColumn. Notice that in this case, the check box control is
         // second control in the Controls collection.
         CheckBox taxCheck = (CheckBox)e.Item.Cells[2].Controls[1];

         String item = e.Item.Cells[1].Text;
         String price = priceText.Text;
       
         DataRow dr;

         // With a database, use an update command.  Since the data source is 
         // an in-memory DataTable, delete the old row and replace it with a new one.

         // Remove old entry.
         StoreView.RowFilter = "Item='" + item + "'";
         if (StoreView.Count > 0)
            StoreView.Delete(0);
         StoreView.RowFilter = "";
 
         // Add new entry.
         dr = Store.NewRow();

         if (taxCheck.Checked)
            dr[0] = "8.6%";
         else 
            dr[0] = "0.0%";
         dr[1] = item;
         dr[2] = price;
         Store.Rows.Add(dr);

         MyDataGrid.EditItemIndex = -1;
         BindGrid();
      }

      void BindGrid() 
      {
         MyDataGrid.DataSource = StoreView;
         MyDataGrid.DataBind();
      }

   </script>

<body>

   <form runat="server">

      <h3>TemplateColumn Example</h3>

      <asp:DataGrid id="MyDataGrid" runat="server"
           BorderColor="black"
           CellPadding="2"        
           OnEditCommand="MyDataGrid_Edit"
           OnCancelCommand="MyDataGrid_Cancel"
           OnUpdateCommand="MyDataGrid_Update"
           ShowFooter="True"
           AutoGenerateColumns="false">

         <Columns>

            <asp:EditCommandColumn
                 EditText="Edit"
                 CancelText="Cancel"
                 UpdateText="Update"
                 ItemStyle-Wrap="false"
                 HeaderText="Edit Controls"/>

            <asp:BoundColumn HeaderText="Description" 
                 ReadOnly="true" 
                 DataField="Item"/>

            <asp:TemplateColumn>

               <HeaderTemplate>
                  <b> Tax </b>
               </HeaderTemplate>

               <ItemTemplate>
                  <asp:Label
                       Text='<%# DataBinder.Eval(Container.DataItem, "Tax") %>'
                       runat="server"/>
               </ItemTemplate>

               <EditItemTemplate>

                  <asp:CheckBox
                       Text="Taxable" 
                       runat="server"/>

               </EditItemTemplate>

               <FooterTemplate>
                  <asp:HyperLink id="HyperLink1"
                       Text="Microsoft"
                       NavigateUrl="http://www.microsoft.com"
                       runat="server"/>
               </FooterTemplate>

            </asp:TemplateColumn>

            <asp:BoundColumn HeaderText="Price" 
                 DataField="Price"/>

         </Columns>

      </asp:DataGrid>

   </form>

</body>
</html>

[C++, JScript] No example is available for C++ or JScript. To view a Visual Basic or C# example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Platforms: Windows 2000, Windows XP Professional, Windows Server 2003 family

See Also

TemplateColumn Class | TemplateColumn Members | System.Web.UI.WebControls Namespace | System.Web.UI.ITemplate | FooterTemplate | ItemTemplate | EditItemTemplate

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