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DataGrid.HeaderStyle Proprietà

Definizione

Ottiene le proprietà di stile della sezione dell'intestazione nel controllo DataGrid.

public:
 virtual property System::Web::UI::WebControls::TableItemStyle ^ HeaderStyle { System::Web::UI::WebControls::TableItemStyle ^ get(); };
[System.Web.UI.PersistenceMode(System.Web.UI.PersistenceMode.InnerProperty)]
public virtual System.Web.UI.WebControls.TableItemStyle HeaderStyle { get; }
[<System.Web.UI.PersistenceMode(System.Web.UI.PersistenceMode.InnerProperty)>]
member this.HeaderStyle : System.Web.UI.WebControls.TableItemStyle
Public Overridable ReadOnly Property HeaderStyle As TableItemStyle

Valore della proprietà

Un oggetto TableItemStyle che contiene le proprietà di stile della sezione dell'intestazione nel controllo DataGrid. Il valore predefinito è un oggetto TableItemStyle vuoto.

Attributi

Esempio

Nell'esempio di codice seguente viene illustrato come utilizzare la HeaderStyle proprietà per impostare il colore di sfondo della sezione intestazione.

<%@ 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 language="C#" runat="server">
 
    ICollection CreateDataSource() 
    {
       DataTable dt = new DataTable();
       DataRow dr;
 
       dt.Columns.Add(new DataColumn("IntegerValue", typeof(Int32)));
       dt.Columns.Add(new DataColumn("StringValue", typeof(string)));
       dt.Columns.Add(new DataColumn("DateTimeValue", typeof(string)));
       dt.Columns.Add(new DataColumn("BoolValue", typeof(bool)));
 
       for (int i = 0; i < 100; i++) {
          dr = dt.NewRow();
 
          dr[0] = i;
          dr[1] = "Item " + i.ToString();
          dr[2] = DateTime.Now.ToShortDateString();
          dr[3] = (i % 2 != 0) ? true : false;
 
          dt.Rows.Add(dr);
       }
 
       DataView dv = new DataView(dt);
       return dv;
    }
 
    void Page_Load(Object sender, EventArgs e) 
    {
       if (chk1.Checked)
          MyDataGrid.PagerStyle.Mode = PagerMode.NumericPages;
       else 
          MyDataGrid.PagerStyle.Mode = PagerMode.NextPrev;
 
       BindGrid();
    }
 
    void MyDataGrid_Page(Object sender, DataGridPageChangedEventArgs e)
   
    {
       MyDataGrid.CurrentPageIndex = e.NewPageIndex;
       BindGrid();
    }
 
    void BindGrid() 
    {
       MyDataGrid.DataSource = CreateDataSource();
       MyDataGrid.DataBind();
       ShowStats();
    }
 
    void ShowStats() 
    {
       lblEnabled.Text = "AllowPaging is " + MyDataGrid.AllowPaging;
       lblCurrentIndex.Text = "CurrentPageIndex is " + MyDataGrid.CurrentPageIndex;
       lblPageCount.Text = "PageCount is " + MyDataGrid.PageCount;
       lblPageSize.Text = "PageSize is " + MyDataGrid.PageSize;
    }
 
 
 </script>
 
 <head runat="server">
    <title>DataGrid Example</title>
</head>
<body>
 
    <h3>DataGrid Example</h3>
 
    <form id="form1" runat="server">
 
       <asp:DataGrid id="MyDataGrid" runat="server"
            AllowPaging="True"
            PageSize="10"            
            ShowFooter="true"
            OnPageIndexChanged="MyDataGrid_Page"
            BorderColor="black"
            BorderWidth="1"
            GridLines="Both"
            CellPadding="3"
            CellSpacing="0"
            Font-Names="Verdana"
            Font-Size="8pt">

          <PagerStyle Mode="NumericPages"
                      HorizontalAlign="Right">
          </PagerStyle>

          <HeaderStyle BackColor="#aaaadd">
          </HeaderStyle>

          <FooterStyle BackColor="#aaaadd">
          </FooterStyle>

          <AlternatingItemStyle BackColor="#eeeeee">
          </AlternatingItemStyle>

       </asp:DataGrid>
 
       <br />
 
       <asp:Checkbox id="chk1" runat="server"
            Text="Show numeric page navigation buttons"
            Font-Names="Verdana"
            Font-Size="8pt"
            AutoPostBack="true"/>
 
       <br />
 
       <table style="background-color:#eeeeee; padding:6">
          <tr>
             <td style="display:inline">
                
 
                   <asp:Label id="lblEnabled" 
                        runat="server"/><br />
                   <asp:Label id="lblCurrentIndex" 
                        runat="server"/><br />
                   <asp:Label id="lblPageCount" 
                        runat="server"/><br />
                   <asp:Label id="lblPageSize" 
                        runat="server"/><br />
 
                
             </td>
          </tr>
       </table>
 
    </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 language="VB" runat="server">
 
    Function CreateDataSource() As ICollection
        Dim dt As New DataTable()
        Dim dr As DataRow
        
        dt.Columns.Add(New DataColumn("IntegerValue", GetType(Int32)))
        dt.Columns.Add(New DataColumn("StringValue", GetType(String)))
        dt.Columns.Add(New DataColumn("DateTimeValue", GetType(String)))
        dt.Columns.Add(New DataColumn("BoolValue", GetType(Boolean)))
        
        Dim i As Integer
        For i = 0 To 99
            dr = dt.NewRow()
            
            dr(0) = i
            dr(1) = "Item " + i.ToString()
            dr(2) = DateTime.Now.ToShortDateString()
            If i Mod 2 <> 0 Then
                dr(3) = True
            Else
                dr(3) = False
            End If
            
            dt.Rows.Add(dr)
        Next i
        
        Dim dv As New DataView(dt)
        Return dv
    End Function 'CreateDataSource


    Sub Page_Load(sender As Object, e As EventArgs)
        If chk1.Checked Then
            MyDataGrid.PagerStyle.Mode = PagerMode.NumericPages
        Else
            MyDataGrid.PagerStyle.Mode = PagerMode.NextPrev
        End If 
        BindGrid()
    End Sub 'Page_Load


    Sub MyDataGrid_Page(sender As Object, e As DataGridPageChangedEventArgs)
        
        MyDataGrid.CurrentPageIndex = e.NewPageIndex
        BindGrid()
    End Sub 'MyDataGrid_Page


    Sub BindGrid()
        MyDataGrid.DataSource = CreateDataSource()
        MyDataGrid.DataBind()
        ShowStats()
    End Sub 'BindGrid


    Sub ShowStats()
        lblEnabled.Text = "AllowPaging is " & MyDataGrid.AllowPaging
        lblCurrentIndex.Text = "CurrentPageIndex is " & MyDataGrid.CurrentPageIndex
        lblPageCount.Text = "PageCount is " & MyDataGrid.PageCount
        lblPageSize.Text = "PageSize is " & MyDataGrid.PageSize
    End Sub 'ShowStats
 
 
 </script>
 
 <head runat="server">
    <title>DataGrid Example</title>
</head>
<body>
 
    <h3>DataGrid Example</h3>
 
    <form id="form1" runat="server">
 
       <asp:DataGrid id="MyDataGrid" runat="server"
            AllowPaging="True"
            PageSize="10"            
            ShowFooter="true"
            OnPageIndexChanged="MyDataGrid_Page"
            BorderColor="black"
            BorderWidth="1"
            GridLines="Both"
            CellPadding="3"
            CellSpacing="0"
            Font-Names="Verdana"
            Font-Size="8pt">

          <PagerStyle Mode="NumericPages"
                      HorizontalAlign="Right">
          </PagerStyle>

          <HeaderStyle BackColor="#aaaadd">
          </HeaderStyle>

          <FooterStyle BackColor="#aaaadd">
          </FooterStyle>

          <AlternatingItemStyle BackColor="#eeeeee">
          </AlternatingItemStyle>

       </asp:DataGrid>
 
       <br />
 
       <asp:Checkbox id="chk1" runat="server"
            Text="Show numeric page navigation buttons"
            Font-Names="Verdana"
            Font-Size="8pt"
            AutoPostBack="true"/>
 
       <br />
 
       <table style="background-color:#eeeeee; padding:6">
          <tr>
             <td style="display:inline">
                
 
                   <asp:Label id="lblEnabled" 
                        runat="server"/><br />
                   <asp:Label id="lblCurrentIndex" 
                        runat="server"/><br />
                   <asp:Label id="lblPageCount" 
                        runat="server"/><br />
                   <asp:Label id="lblPageSize" 
                        runat="server"/><br />
 
                
             </td>
          </tr>
       </table>
 
    </form>
 
 </body>
 </html>

<%@ 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">
 
      ICollection CreateDataSource() 
      {
      
         // Create sample data for the DataGrid control.
         DataTable dt = new DataTable();
         DataRow dr;
 
         // Define the columns of the table.
         dt.Columns.Add(new DataColumn("IntegerValue", typeof(Int32)));
         dt.Columns.Add(new DataColumn("StringValue", typeof(string)));
         dt.Columns.Add(new DataColumn("CurrencyValue", typeof(double)));
 
         // Populate the table with sample values.
         for (int i = 0; i < 5; i++) 
         {
            dr = dt.NewRow();
 
            dr[0] = i;
            dr[1] = "Item " + i.ToString();
            dr[2] = 1.23 * (i + 1);
 
            dt.Rows.Add(dr);
         }
 
         DataView dv = new DataView(dt);
         return dv;
      }
 
      void Page_Load(Object sender, EventArgs e) 
      {
 
         // Load sample data only once when the page is first loaded.
         if (!IsPostBack) 
         {
            ItemsGrid.DataSource = CreateDataSource();
            ItemsGrid.DataBind();
         }

      }

      void Button_Click(Object sender, EventArgs e) 
      {

         // Count the number of selected items in the DataGrid control.
         int count = 0;

         // Display the selected times.
         Message.Text = "You Selected: <br />";

         // Iterate through each item (row) in the DataGrid control and determine
         // whether it is selected.
         foreach (DataGridItem item in ItemsGrid.Items)
         {

            DetermineSelection(item, ref count);        

         }

         // If no items are selected, display the appropriate message.
         if (count == 0)
         {

            Message.Text = "Not items selected";

         }

      }

      void DetermineSelection(DataGridItem item, ref int count)
      {

         // Retrieve the SelectCheckBox CheckBox control from the specified item (row) in the 
         // DataGrid control.
         CheckBox selection = (CheckBox)item.FindControl("SelectCheckBox");

         // If the item is selected, display the appropriate message and increment the count
         // of selected items.
         if (selection != null)
         {

           if (selection.Checked)
           {
              Message.Text += "- " + item.Cells[1].Text + "<br />";
              count++;
           }

         }    

      }

      void Selection_Change(Object sender, EventArgs e)
      {

         // Set the background color for the heading and footer sections of
         // the DataGrid control.
         ItemsGrid.HeaderStyle.BackColor = System.Drawing.Color.FromName(List.SelectedItem.Value);
         ItemsGrid.FooterStyle.BackColor = System.Drawing.Color.FromName(List.SelectedItem.Value);

      }

   </script>
 
<head runat="server">
    <title>DataGrid HeaderStyle and FooterStyle Example</title>
</head>
<body>
 
   <form id="form1" runat="server">
 
      <h3>DataGrid HeaderStyle and FooterStyle Example</h3>

      Select a backcolor for the header and footer sections.

      <br /><br />
 
      <b>Product List</b>
 
      <asp:DataGrid id="ItemsGrid"
           BorderColor="black"
           BorderWidth="1"
           CellPadding="3"
           ShowFooter="True"
           AutoGenerateColumns="False"
           runat="server">

         <HeaderStyle BackColor="White">
         </HeaderStyle>

         <FooterStyle BackColor="White">
         </FooterStyle>

         <Columns>

            <asp:BoundColumn DataField="IntegerValue" 
                 HeaderText="Item"/>

            <asp:BoundColumn DataField="StringValue" 
                 HeaderText="Description"/>

            <asp:BoundColumn DataField="CurrencyValue" 
                 HeaderText="Price"
                 DataFormatString="{0:c}">

               <ItemStyle HorizontalAlign="Right">
               </ItemStyle>

            </asp:BoundColumn>

            <asp:TemplateColumn HeaderText="Select Item">

               <ItemTemplate>

                  <asp:CheckBox id="SelectCheckBox"
                       Text="Add to Cart"
                       Checked="False"
                       runat="server"/>

               </ItemTemplate>

            </asp:TemplateColumn>
 
         </Columns> 
 
      </asp:DataGrid>

      <br /><br />

      <asp:Button id="SubmitButton"
           Text="Submit"
           OnClick = "Button_Click"
           runat="server"/>

      <br /><br />

      <asp:Label id="Message"
           runat="server"/>

      <hr />

      Header and footer backcolor: <br /> 

      <asp:DropDownList id="List"
           AutoPostBack="True"
           OnSelectedIndexChanged="Selection_Change"
           runat="server">

         <asp:ListItem Selected="True" Value="White"> White </asp:ListItem>
         <asp:ListItem Value="Silver"> Silver </asp:ListItem>
         <asp:ListItem Value="DarkGray"> Dark Gray </asp:ListItem>
         <asp:ListItem Value="Khaki"> Khaki </asp:ListItem>
         <asp:ListItem Value="DarkKhaki"> Dark Khaki </asp:ListItem>

      </asp:DropDownList>
 
   </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">
 
      Function CreateDataSource() As ICollection 
      
         ' Create sample data for the DataGrid control.
         Dim dt As DataTable = New DataTable()
         Dim dr As DataRow
 
         ' Define the columns of the table.
         dt.Columns.Add(New DataColumn("IntegerValue", GetType(Int32)))
         dt.Columns.Add(New DataColumn("StringValue", GetType(string)))
         dt.Columns.Add(New DataColumn("CurrencyValue", GetType(double)))
 
         ' Populate the table with sample values.
         Dim i As Integer

         For i = 0 to 4 
        
            dr = dt.NewRow()
 
            dr(0) = i
            dr(1) = "Item " & i.ToString()
            dr(2) = 1.23 * (i + 1)
 
            dt.Rows.Add(dr)

         Next i
 
         Dim dv As DataView = New DataView(dt)
         Return dv

      End Function
 
      Sub Page_Load(sender As Object, e As EventArgs) 
 
         ' Load sample data only once when the page is first loaded.
         If Not IsPostBack Then 
  
            ItemsGrid.DataSource = CreateDataSource()
            ItemsGrid.DataBind()

         End If

      End Sub

      Sub Button_Click(sender As Object, e As EventArgs) 

         ' Count the number of selected items in the DataGrid control.
         Dim count As Integer = 0

         ' Display the selected times.
         Message.Text = "You Selected: <br />"

         ' Iterate through each item (row) in the DataGrid control and determine
         ' whether it is selected.
         Dim item As DataGridItem
 
         For Each item In ItemsGrid.Items

            DetermineSelection(item, count)        

         Next

         ' If no items are selected, display the appropriate message.
         If count = 0 Then

            Message.Text = "Not items selected"

         End If

      End Sub

      Sub DetermineSelection(item As DataGridItem, ByRef count As Integer)

         ' Retrieve the SelectCheckBox CheckBox control from the specified item (row) in the 
         ' DataGrid control.
         Dim selection As CheckBox = CType(item.FindControl("SelectCheckBox"), CheckBox)

         ' If the item is selected, display the appropriate message and increment the count
         ' of selected items.
         If Not selection Is Nothing Then

           If selection.Checked Then
           
              Message.Text &= "- " & item.Cells(1).Text & "<br />"
              count = count + 1
           
           End If

         End If    

      End Sub

      Sub Selection_Change(sender As Object, e As EventArgs)

         ' Set the background color for the heading and footer sections of
         ' the DataGrid control.
         ItemsGrid.HeaderStyle.BackColor = System.Drawing.Color.FromName(List.SelectedItem.Value)
         ItemsGrid.FooterStyle.BackColor = System.Drawing.Color.FromName(List.SelectedItem.Value)

      End Sub

   </script>
 
<head runat="server">
    <title>DataGrid HeaderStyle and FooterStyle Example</title>
</head>
<body>
 
   <form id="form1" runat="server">
 
      <h3>DataGrid HeaderStyle and FooterStyle Example</h3>

      Select a backcolor for the header and footer sections.

      <br /><br />
 
      <b>Product List</b>
 
      <asp:DataGrid id="ItemsGrid"
           BorderColor="black"
           BorderWidth="1"
           CellPadding="3"
           ShowFooter="True"
           AutoGenerateColumns="False"
           runat="server">

         <HeaderStyle BackColor="White">
         </HeaderStyle>

         <FooterStyle BackColor="White">
         </FooterStyle>

         <Columns>

            <asp:BoundColumn DataField="IntegerValue" 
                 HeaderText="Item"/>

            <asp:BoundColumn DataField="StringValue" 
                 HeaderText="Description"/>

            <asp:BoundColumn DataField="CurrencyValue" 
                 HeaderText="Price"
                 DataFormatString="{0:c}">

               <ItemStyle HorizontalAlign="Right">
               </ItemStyle>

            </asp:BoundColumn>

            <asp:TemplateColumn HeaderText="Select Item">

               <ItemTemplate>

                  <asp:CheckBox id="SelectCheckBox"
                       Text="Add to Cart"
                       Checked="False"
                       runat="server"/>

               </ItemTemplate>

            </asp:TemplateColumn>
 
         </Columns> 
 
      </asp:DataGrid>

      <br /><br />

      <asp:Button id="SubmitButton"
           Text="Submit"
           OnClick = "Button_Click"
           runat="server"/>

      <br /><br />

      <asp:Label id="Message"
           runat="server"/>

      <hr />

      Header and footer backcolor: <br /> 

      <asp:DropDownList id="List"
           AutoPostBack="True"
           OnSelectedIndexChanged="Selection_Change"
           runat="server">

         <asp:ListItem Selected="True" Value="White"> White </asp:ListItem>
         <asp:ListItem Value="Silver"> Silver </asp:ListItem>
         <asp:ListItem Value="DarkGray"> Dark Gray </asp:ListItem>
         <asp:ListItem Value="Khaki"> Khaki </asp:ListItem>
         <asp:ListItem Value="DarkKhaki"> Dark Khaki </asp:ListItem>

      </asp:DropDownList>
 
   </form>
 
</body>
</html>

Commenti

Utilizzare questa proprietà per fornire uno stile personalizzato per la sezione intestazione del DataGrid controllo . Gli attributi di stile comuni che possono essere modificati includono forecolor, backcolor, font e allineamento del contenuto all'interno della cella. L'aggiunta di uno stile diverso migliora l'aspetto del DataGrid controllo.

La HeaderStyle proprietà del DataGrid controllo eredita le impostazioni di stile della ControlStyle proprietà . Ad esempio, se si specifica un tipo di carattere rosso per la ControlStyle proprietà, anche la HeaderStyle proprietà avrà un tipo di carattere rosso. In questo modo è possibile fornire un aspetto comune per il controllo impostando una singola proprietà di stile. È possibile eseguire l'override delle impostazioni di stile ereditate impostando la HeaderStyle proprietà . Ad esempio, è possibile specificare un tipo di carattere blu per la HeaderStyle proprietà, sostituendo il tipo di carattere rosso specificato nella ControlStyle proprietà .

Per specificare uno stile personalizzato per la sezione intestazione, posizionare i tag tra i <HeaderStyle> tag di apertura e chiusura del DataGrid controllo. È quindi possibile elencare gli attributi di stile all'interno del tag di apertura <HeaderStyle> .

Nota

La ShowHeader proprietà deve essere impostata su true affinché questa proprietà sia visibile.

Si applica a

Vedi anche