DataGridPageChangedEventHandler Delegate

Definition

Represents the method that handles the PageIndexChanged event of the DataGrid control.

C#
public delegate void DataGridPageChangedEventHandler(object source, DataGridPageChangedEventArgs e);

Parameters

source
Object

The source of the event.

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

The PageIndexChanged event is raised when a button in the page selection element of the DataGrid control is clicked.

When you create a DataGridPageChangedEventHandler delegate, you identify the method that will handle the event. To associate the event with your event handler, add an instance of the delegate to the event. The event handler is called whenever the event occurs, unless you remove the delegate. For more information about event handler delegates, see Handling and Raising Events.

Extension Methods

GetMethodInfo(Delegate)

Gets an object that represents the method represented by the specified delegate.

Applies to

Product Versions
.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