DataGrid.CurrentPageIndex Proprietà

  • Riferimento

Definizione

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

Ottiene o imposta l'indice della pagina attualmente visualizzata.

public:
 property int CurrentPageIndex { int get(); void set(int value); };
[System.ComponentModel.Bindable(true)]
[System.ComponentModel.Browsable(false)]
public int CurrentPageIndex { get; set; }
[System.ComponentModel.Browsable(false)]
public int CurrentPageIndex { get; set; }
[<System.ComponentModel.Bindable(true)>]
[<System.ComponentModel.Browsable(false)>]
member this.CurrentPageIndex : int with get, set
[<System.ComponentModel.Browsable(false)>]
member this.CurrentPageIndex : int with get, set
Public Property CurrentPageIndex As Integer

Valore della proprietà

Int32

L'indice in base zero della pagina attualmente visualizzata.

Attributi
BindableAttribute BrowsableAttribute

Eccezioni

ArgumentOutOfRangeException

L'indice della pagina specificata è un valore negativo.

Esempio

Nell'esempio di codice seguente viene illustrato come usare la proprietà per controllare a livello di codice la CurrentPageIndex pagina da visualizzare nel DataGrid controllo.

<%@ 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 < 200; 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.Visible=true;
         else
            MyDataGrid.PagerStyle.Visible=false;    

         BindGrid();
      }

      void PagerButtonClick(Object sender, EventArgs e) 
      {
         // Used by external paging UI.
         String arg = ((LinkButton)sender).CommandArgument;

         switch(arg)
         {
            case ("next"):
               if (MyDataGrid.CurrentPageIndex < (MyDataGrid.PageCount - 1))
                  MyDataGrid.CurrentPageIndex ++;
               break;
            case ("prev"):
               if (MyDataGrid.CurrentPageIndex > 0)
                  MyDataGrid.CurrentPageIndex --;
               break;
            case ("last"):
               MyDataGrid.CurrentPageIndex = (MyDataGrid.PageCount - 1);
               break;
            default:

               // Page number.
               MyDataGrid.CurrentPageIndex = Convert.ToInt32(arg);
               break;
         }
         BindGrid();
      }

      void MyDataGrid_Page(Object sender, DataGridPageChangedEventArgs e) 
      {
         // Used by built-in pager.  CurrentPageIndex is already set.
         BindGrid();
      }

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

      void ShowStats() 
      {
         lblCurrentIndex.Text = "CurrentPageIndex is " + MyDataGrid.CurrentPageIndex;
         lblPageCount.Text = "PageCount is " + MyDataGrid.PageCount;
      }


   </script>

<head runat="server">
    <title>DataGrid Custom Paging Controls</title>
</head>
<body>

   <form id="form1" runat="server">

      <h3>DataGrid Custom Paging Controls</h3>

      <asp:DataGrid id="MyDataGrid"
           AllowPaging="True"
           PageSize="10"
           OnPageIndexChanged="MyDataGrid_Page"
           BorderColor="black"
           BorderWidth="1"
           GridLines="Both"
           CellPadding="3"
           CellSpacing="0"
           Font-Names="Verdana"
           Font-Size="8pt"
           runat="server">

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

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

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

      </asp:DataGrid>

      <br />

      <asp:LinkButton id="btnPrev"
           Text="Previous page"
           CommandArgument="prev"
           ForeColor="navy"
           Font-Names="Verdana"
           Font-Size="8pt"
           OnClick="PagerButtonClick"
           runat="server"/>

       

      <asp:LinkButton id="btnNext"
           Text="Next page"
           CommandArgument="next"
           ForeColor="navy"
           Font-Names="Verdana"
           Font-Size="8pt"
           OnClick="PagerButtonClick"
           runat="server"/>

       

      <asp:LinkButton id="btnPage8" runat="server"
           Text="Go to Page 8"
           CommandArgument="7"
           ForeColor="navy"
           Font-Names="Verdana"
           Font-Size="8pt"
           OnClick="PagerButtonClick"/>

       
 
      <asp:LinkButton id="btnFirst"
           Text="Go to the first page"
           CommandArgument="0"
           ForeColor="navy"
           Font-Names="Verdana"
           Font-Size="8pt"
           OnClick="PagerButtonClick"
           runat="server"/>

       

      <asp:LinkButton id="btnLast"
           Text="Go to the last page"
           CommandArgument="last"
           ForeColor="navy"
           Font-Names="Verdana"
           Font-Size="8pt"
           OnClick="PagerButtonClick"
           runat="server"/>

      <br />

      <asp:Checkbox id="chk1"
           Text="Show built-in pager"
           Font-Names="Verdana"
           Font-Size="8pt"
           AutoPostBack="true"
           runat="server"/>

      <br />

      <table style="background-color:#eeeeee; padding:6">
         <tr>
            <td style="display:inline">
               

                  <asp:Label id="lblCurrentIndex" 
                       runat="server" />
                  <br />

                  <asp:Label id="lblPageCount" 
                       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 199
            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.Visible = True
        Else
            MyDataGrid.PagerStyle.Visible = False
        End If 
        BindGrid()
    End Sub 'Page_Load


    Sub PagerButtonClick(sender As Object, e As EventArgs)
        ' Used by external paging UI.
        Dim arg As String = CType(sender, LinkButton).CommandArgument
        
        Select Case arg
            Case "next"
                If MyDataGrid.CurrentPageIndex < MyDataGrid.PageCount - 1 Then
                    MyDataGrid.CurrentPageIndex += 1
                End If
            Case "prev"
                If MyDataGrid.CurrentPageIndex > 0 Then
                    MyDataGrid.CurrentPageIndex -= 1
                End If
            Case "last"
                MyDataGrid.CurrentPageIndex = MyDataGrid.PageCount - 1
            Case Else

                ' Page number.
                MyDataGrid.CurrentPageIndex = Convert.ToInt32(arg)
        End Select
        BindGrid()
    End Sub 'PagerButtonClick


    Sub MyDataGrid_Page(sender As Object, e As DataGridPageChangedEventArgs)
        ' Used by built-in pager.  CurrentPageIndex is already set.
        BindGrid()
    End Sub 'MyDataGrid_Page


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


    Sub ShowStats()
        lblCurrentIndex.Text = "CurrentPageIndex is " & MyDataGrid.CurrentPageIndex
        lblPageCount.Text = "PageCount is " & MyDataGrid.PageCount
    End Sub 'ShowStats

   </script>

<head runat="server">
    <title>DataGrid Custom Paging Controls</title>
</head>
<body>

   <form id="form1" runat="server">

      <h3>DataGrid Custom Paging Controls</h3>

      <asp:DataGrid id="MyDataGrid"
           AllowPaging="True"
           PageSize="10"
           OnPageIndexChanged="MyDataGrid_Page"
           BorderColor="black"
           BorderWidth="1"
           GridLines="Both"
           CellPadding="3"
           CellSpacing="0"
           Font-Names="Verdana"
           Font-Size="8pt"
           runat="server">

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

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

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

      </asp:DataGrid>

      <br />

      <asp:LinkButton id="btnPrev"
           Text="Previous page"
           CommandArgument="prev"
           ForeColor="navy"
           Font-Names="Verdana"
           Font-Size="8pt"
           OnClick="PagerButtonClick"
           runat="server"/>

       

      <asp:LinkButton id="btnNext"
           Text="Next page"
           CommandArgument="next"
           ForeColor="navy"
           Font-Names="Verdana"
           Font-Size="8pt"
           OnClick="PagerButtonClick"
           runat="server"/>

       

      <asp:LinkButton id="btnPage8" runat="server"
           Text="Go to Page 8"
           CommandArgument="7"
           ForeColor="navy"
           Font-Names="Verdana"
           Font-Size="8pt"
           OnClick="PagerButtonClick"/>

       
 
      <asp:LinkButton id="btnFirst"
           Text="Go to the first page"
           CommandArgument="0"
           ForeColor="navy"
           Font-Names="Verdana"
           Font-Size="8pt"
           OnClick="PagerButtonClick"
           runat="server"/>

       

      <asp:LinkButton id="btnLast"
           Text="Go to the last page"
           CommandArgument="last"
           ForeColor="navy"
           Font-Names="Verdana"
           Font-Size="8pt"
           OnClick="PagerButtonClick"
           runat="server"/>

      <br />

      <asp:Checkbox id="chk1"
           Text="Show built-in pager"
           Font-Names="Verdana"
           Font-Size="8pt"
           AutoPostBack="true"
           runat="server"/>

      <br />

      <table style="background-color:#eeeeee; padding:6">
         <tr>
            <td style="display:inline">
               

                  <asp:Label id="lblCurrentIndex" 
                       runat="server" />
                  <br />

                  <asp:Label id="lblPageCount" 
                       runat="server" />
                  <br />

               
            </td>
         </tr>
      </table>
   </form>

</body>
</html>

<%@ 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>

<%@ Page Language="VB" %>
<%@ 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">
    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 100
            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(ByVal sender As Object, ByVal 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 Check_Change(ByVal sender As Object, ByVal e As EventArgs)
        ' 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()
    End Sub

    Sub Grid_Change(ByVal sender As Object, ByVal e As DataGridPageChangedEventArgs)
        ' 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()
    End Sub
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head2" runat="server">
    <title></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 ID="Label1" runat="server" 
        AssociatedControlID="ItemsGrid" 
        Font-Bold="true">Product List</asp:Label>
    <asp:DataGrid id="ItemsGrid" runat="server"
        BorderColor="Gray"
        BorderWidth="1"
        CellPadding="3"
        UseAccessibleHeader="true"
        AutoGenerateColumns="False"
        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>

Commenti

Usare questa proprietà per determinare la pagina attualmente visualizzata nel DataGrid controllo quando il paging è abilitato. Questa proprietà viene usata anche per controllare a livello di codice la pagina visualizzata.

È anche possibile nascondere i controlli di paging predefiniti e creare controlli personalizzati. Per visualizzare una pagina specifica, impostare questa proprietà sull'indice di pagina da visualizzare e quindi ribinare i dati al DataGrid controllo.

Si applica a

Vedi anche