TemplateColumn.HeaderTemplate Proprietà

  • Riferimento

Definizione

Spazio dei nomi:
System.Web.UI.WebControls
Assembly:
System.Web.dll

Ottiene o imposta il modello per visualizzare la sezione di intestazione dell'oggetto TemplateColumn.

public:
 virtual property System::Web::UI::ITemplate ^ HeaderTemplate { System::Web::UI::ITemplate ^ get(); void set(System::Web::UI::ITemplate ^ value); };
[System.ComponentModel.Browsable(false)]
[System.Web.UI.PersistenceMode(System.Web.UI.PersistenceMode.InnerProperty)]
[System.Web.UI.TemplateContainer(typeof(System.Web.UI.WebControls.DataGridItem))]
public virtual System.Web.UI.ITemplate HeaderTemplate { get; set; }
[<System.ComponentModel.Browsable(false)>]
[<System.Web.UI.PersistenceMode(System.Web.UI.PersistenceMode.InnerProperty)>]
[<System.Web.UI.TemplateContainer(typeof(System.Web.UI.WebControls.DataGridItem))>]
member this.HeaderTemplate : System.Web.UI.ITemplate with get, set
Public Overridable Property HeaderTemplate As ITemplate

Valore della proprietà

ITemplate

Oggetto implementato da ITemplate contenente il modello per visualizzare la sezione di intestazione dell'oggetto TemplateColumn. Il valore predefinito è null, a indicare che questa proprietà non è impostata.

Attributi
BrowsableAttribute PersistenceModeAttribute TemplateContainerAttribute

Esempio

Nell'esempio di codice seguente viene illustrato come utilizzare la HeaderTemplate proprietà per controllare l'aspetto della sezione intestazione nell'oggetto TemplateColumn .


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

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
   <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>

<head runat="server">
    <title>TemplateColumn Example</title>
</head>
<body>

   <form id="form1" 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>


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

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
   <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>

<head runat="server">
    <title>TemplateColumn Example</title>
</head>
<body>

   <form id="form1" 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>

Commenti

Utilizzare la HeaderTemplate proprietà per controllare l'aspetto della sezione intestazione nell'oggetto TemplateColumn . L'aspetto viene specificato creando un modello che definisce la modalità di rendering dell'elemento nella colonna. Per specificare un modello per l'elemento selezionato per la modifica, posizionare prima i tag di apertura e chiusura <HeaderTemplate> tra i tag di apertura e chiusura dell'elemento <TemplateColumn> . È quindi possibile elencare il contenuto che controlla l'aspetto dell'elemento tra i tag di apertura e chiusura <HeaderTemplate> . Il contenuto può essere semplice come testo normale o può essere reso più complesso incorporando altri controlli nel modello.

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