DataGrid.OnPageIndexChanged(DataGridPageChangedEventArgs) Method

Definition

Raises the PageIndexChanged event. This allows you to provide a custom handler for the event.

C#
protected virtual void OnPageIndexChanged(System.Web.UI.WebControls.DataGridPageChangedEventArgs e);

Parameters

Examples

The following code example demonstrates how to specify and code a handler for the PageIndexChanged event. It displays pages on the DataGrid control in 10-item increments.

ASP.NET (C#)
<%@ Page Language="C#" %>
<%@ Import Namespace="System.Data" %>

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

<script runat="server">
    private 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 <= 100; 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;
    }

    private 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();
        }
    }

    private void Check_Change(Object sender, EventArgs e)
    {
        // Allow or prevent paging depending 
        // on the user's selection.
        ItemsGrid.AllowPaging = AllowPagingCheckBox.Checked;

        // Rebind the data to refresh the DataGrid control. 
        ItemsGrid.DataSource = CreateDataSource();
        ItemsGrid.DataBind();
    }

    private void Grid_Change(Object sender, DataGridPageChangedEventArgs e) 
    {
        // For the DataGrid control to navigate to the correct page when
        // paging is allowed, the CurrentPageIndex property must be updated
        // programmatically. This process is usually accomplished in the
        // event-handling method for the PageIndexChanged event.

        // Set CurrentPageIndex to the page the user clicked.
        ItemsGrid.CurrentPageIndex = e.NewPageIndex;

        // Rebind the data to refresh the DataGrid control. 
        ItemsGrid.DataSource = CreateDataSource();
        ItemsGrid.DataBind();
    }
</script>
 
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
    <title>DataGrid AllowPaging Example</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
 
    <h3>DataGrid AllowPaging Example</h3>

    <p>Select whether to allow paging in the DataGrid control.<br />
       <asp:CheckBox id="AllowPagingCheckBox"
            Text="Allow paging"
            AutoPostBack="True"
            Checked="True"
            OnCheckedChanged="Check_Change"
            runat="server" />
    </p>
    <hr />
    <asp:Label runat="server" 
        AssociatedControlID="ItemsGrid" 
        Font-Bold="true">Product List</asp:Label>
    <asp:DataGrid id="ItemsGrid" runat="server"
        BorderColor="Gray"
        BorderWidth="1"
        CellPadding="3"
        AutoGenerateColumns="False"
        UseAccessibleHeader="true"
        PageSize="10"
        AllowPaging="True"
        OnPageIndexChanged="Grid_Change">

        <HeaderStyle BackColor="LightBlue" />
        <Columns>
            <asp:BoundColumn DataField="IntegerValue" 
                 SortExpression="IntegerValue"
                 ItemStyle-HorizontalAlign="center"
                 HeaderText="Item" />

            <asp:BoundColumn DataField="StringValue" 
                HeaderText="Description" 
                ItemStyle-HorizontalAlign="left"
                SortExpression="StringValue" />

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

        </Columns>
        <ItemStyle HorizontalAlign="Right" />
    </asp:DataGrid>

    </div>
    </form>
</body>
</html>
ASP.NET (C#)

<%@ 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<=100; 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();
         
         }

         // Manually register the event-handling method for the PageIndexChanged  
         // event of the DataGrid control.
         ItemsGrid.PageIndexChanged += new DataGridPageChangedEventHandler(this.Grid_Change);

      }

      void Check_Change(Object sender, EventArgs e)
      {
   
         // Allow or prevent paging depending on the user's selection.
         if (AllowPagingCheckBox.Checked)
         {

            ItemsGrid.AllowPaging = true;

         }
         else
         {

            ItemsGrid.AllowPaging = false;

         }

         // Re-bind the data to refresh the DataGrid control. 
         ItemsGrid.DataSource = CreateDataSource();
         ItemsGrid.DataBind();

      }

      void Grid_Change(Object sender, DataGridPageChangedEventArgs e) 
      {
 
         // For the DataGrid control to navigate to the correct page when paging is
         // allowed, the CurrentPageIndex property must be programmatically updated.
         // This process is usually accomplished in the event-handling method for the
         // PageIndexChanged event.

         // Set CurrentPageIndex to the page the user clicked.
         ItemsGrid.CurrentPageIndex = e.NewPageIndex;

         // Re-bind the data to refresh the DataGrid control. 
         ItemsGrid.DataSource = CreateDataSource();
         ItemsGrid.DataBind();
      
      }

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

      Select whether to allow paging in the DataGrid control.

      <br /><br />
 
      <b>Product List</b>
 
      <asp:DataGrid id="ItemsGrid"
           BorderColor="black"
           BorderWidth="1"
           CellPadding="3"
           AutoGenerateColumns="False"
           PageSize="10"
           AllowPaging="True"
           runat="server">

         <HeaderStyle BackColor="#00aaaa">
         </HeaderStyle>

         <Columns>

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

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

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

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

            </asp:BoundColumn>

         </Columns> 
 
      </asp:DataGrid>

      <hr />

      <table cellpadding="5">

         <tr>

            <td>

               <asp:CheckBox id="AllowPagingCheckBox"
                    Text="Allow paging"
                    AutoPostBack="True"
                    Checked="True"
                    OnCheckedChanged="Check_Change"
                    runat="server"/>

            </td>
            
         </tr>

      </table>
 
   </form>
 
</body>
</html>

Remarks

Use the OnPageIndexChanged method to provide a custom handler for the PageIndexChanged event.

The PageIndexChanged event is raised when one of the page selection elements is clicked.

A typical handler for the PageIndexChanged event sets the CurrentPageIndex property to the index of the page you want to display and then uses the DataBind method to bind the data to the DataGrid control.

Poznámka

The event handler receives a DataGridPageChangedEventArgs object as a parameter. You can use the NewPageIndex property of this parameter to determine the index of the page selected by the user from the page selection elements of the DataGrid control.

Raising an event invokes the event handler through a delegate. For more information, see Handling and Raising Events.

Notes to Inheritors

When overriding OnPageIndexChanged(DataGridPageChangedEventArgs) in a derived class, be sure to call the base class's OnPageIndexChanged(DataGridPageChangedEventArgs) method.

For more information about how to handle events, see Handling and Raising Events.

Applies to

Produkt Verzie
.NET Framework 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1

See also