GridView.PageIndex Proprietà
Definizione
Importante
Alcune informazioni sono relative alla release non definitiva del prodotto, che potrebbe subire modifiche significative prima della release definitiva. Microsoft non riconosce alcuna garanzia, espressa o implicita, in merito alle informazioni qui fornite.
Ottiene o imposta l'indice della pagina attualmente visualizzata.
public:
virtual property int PageIndex { int get(); void set(int value); };[System.ComponentModel.Browsable(true)]
public virtual int PageIndex { get; set; }[<System.ComponentModel.Browsable(true)>]
member this.PageIndex : int with get, setPublic Overridable Property PageIndex As IntegerValore della proprietà
L'indice in base zero della pagina attualmente visualizzata.
- Attributi
Eccezioni
La proprietà PageIndex è impostata su un valore minore di 0.
Esempio
Nell'esempio seguente viene illustrato come usare la PageIndex proprietà per determinare l'indice della pagina attualmente visualizzata nel GridView controllo. L'esempio mostra anche come PageIndex la proprietà può essere usata per specificare quale pagina viene visualizzata dopo che l'utente seleziona un valore dalla riga del pager.
<%@ Page language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
protected void PageDropDownList_SelectedIndexChanged(Object sender, EventArgs e)
{
// Retrieve the pager row.
GridViewRow pagerRow = CustomersGridView.BottomPagerRow;
// Retrieve the PageDropDownList DropDownList from the bottom pager row.
DropDownList pageList = (DropDownList)pagerRow.Cells[0].FindControl("PageDropDownList");
// Set the PageIndex property to display that page selected by the user.
CustomersGridView.PageIndex = pageList.SelectedIndex;
}
protected void CustomersGridView_DataBound(Object sender, EventArgs e)
{
// Retrieve the pager row.
GridViewRow pagerRow = CustomersGridView.BottomPagerRow;
// Retrieve the DropDownList and Label controls from the row.
DropDownList pageList = (DropDownList)pagerRow.Cells[0].FindControl("PageDropDownList");
Label pageLabel = (Label)pagerRow.Cells[0].FindControl("CurrentPageLabel");
if(pageList != null)
{
// Create the values for the DropDownList control based on
// the total number of pages required to display the data
// source.
for(int i=0; i<CustomersGridView.PageCount; i++)
{
// Create a ListItem object to represent a page.
int pageNumber = i + 1;
ListItem item = new ListItem(pageNumber.ToString());
// If the ListItem object matches the currently selected
// page, flag the ListItem object as being selected. Because
// the DropDownList control is recreated each time the pager
// row gets created, this will persist the selected item in
// the DropDownList control.
if(i==CustomersGridView.PageIndex)
{
item.Selected = true;
}
// Add the ListItem object to the Items collection of the
// DropDownList.
pageList.Items.Add(item);
}
}
if(pageLabel != null)
{
// Calculate the current page number.
int currentPage = CustomersGridView.PageIndex + 1;
// Update the Label control with the current page information.
pageLabel.Text = "Page " + currentPage.ToString() +
" of " + CustomersGridView.PageCount.ToString();
}
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>GridView PagerTemplate Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>GridView PagerTemplate Example</h3>
<asp:gridview id="CustomersGridView"
datasourceid="CustomersSqlDataSource"
autogeneratecolumns="true"
allowpaging="true"
ondatabound="CustomersGridView_DataBound"
runat="server">
<pagerstyle forecolor="Blue"
backcolor="LightBlue"/>
<pagertemplate>
<table width="100%">
<tr>
<td style="width:70%">
<asp:label id="MessageLabel"
forecolor="Blue"
text="Select a page:"
runat="server"/>
<asp:dropdownlist id="PageDropDownList"
autopostback="true"
onselectedindexchanged="PageDropDownList_SelectedIndexChanged"
runat="server"/>
</td>
<td style="width:70%; text-align:right">
<asp:label id="CurrentPageLabel"
forecolor="Blue"
runat="server"/>
</td>
</tr>
</table>
</pagertemplate>
</asp:gridview>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the Northwind sample database. Use an ASP.NET -->
<!-- expression to retrieve the connection string value -->
<!-- from the Web.config file. -->
<asp:sqldatasource id="CustomersSqlDataSource"
selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
runat="server">
</asp:sqldatasource>
</form>
</body>
</html>
<%@ Page language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
Protected Sub PageDropDownList_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
' Retrieve the pager row.
Dim pagerRow As GridViewRow = CustomersGridView.BottomPagerRow
' Retrieve the PageDropDownList DropDownList from the bottom pager row.
Dim pageList As DropDownList = CType(pagerRow.Cells(0).FindControl("PageDropDownList"), DropDownList)
' Set the PageIndex property to display that page selected by the user.
CustomersGridView.PageIndex = pageList.SelectedIndex
End Sub
Protected Sub CustomersGridView_DataBound(ByVal sender As Object, ByVal e As EventArgs)
' Retrieve the pager row.
Dim pagerRow As GridViewRow = CustomersGridView.BottomPagerRow
' Retrieve the DropDownList and Label controls from the row.
Dim pageList As DropDownList = CType(pagerRow.Cells(0).FindControl("PageDropDownList"), DropDownList)
Dim pageLabel As Label = CType(pagerRow.Cells(0).FindControl("CurrentPageLabel"), Label)
If Not pageList Is Nothing Then
' Create the values for the DropDownList control based on
' the total number of pages required to display the data
' source.
Dim i As Integer
For i = 0 To CustomersGridView.PageCount - 1
' Create a ListItem object to represent a page.
Dim pageNumber As Integer = i + 1
Dim item As ListItem = New ListItem(pageNumber.ToString())
' If the ListItem object matches the currently selected
' page, flag the ListItem object as being selected. Because
' the DropDownList control is recreated each time the pager
' row gets created, this will persist the selected item in
' the DropDownList control.
If i = CustomersGridView.PageIndex Then
item.Selected = True
End If
' Add the ListItem object to the Items collection of the
' DropDownList.
pageList.Items.Add(item)
Next i
End If
If Not pageLabel Is Nothing Then
' Calculate the current page number.
Dim currentPage As Integer = CustomersGridView.PageIndex + 1
' Update the Label control with the current page information.
pageLabel.Text = "Page " & currentPage.ToString() & _
" of " & CustomersGridView.PageCount.ToString()
End If
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>GridView PagerTemplate Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>GridView PagerTemplate Example</h3>
<asp:gridview id="CustomersGridView"
datasourceid="CustomersSqlDataSource"
autogeneratecolumns="true"
allowpaging="true"
ondatabound="CustomersGridView_DataBound"
runat="server">
<pagerstyle forecolor="Blue"
backcolor="LightBlue"/>
<pagertemplate>
<table width="100%">
<tr>
<td style="width:70%">
<asp:label id="MessageLabel"
forecolor="Blue"
text="Select a page:"
runat="server"/>
<asp:dropdownlist id="PageDropDownList"
autopostback="true"
onselectedindexchanged="PageDropDownList_SelectedIndexChanged"
runat="server"/>
</td>
<td style="width:70%; text-align:right">
<asp:label id="CurrentPageLabel"
forecolor="Blue"
runat="server"/>
</td>
</tr>
</table>
</pagertemplate>
</asp:gridview>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the Northwind sample database. Use an ASP.NET -->
<!-- expression to retrieve the connection string value -->
<!-- from the Web.config file. -->
<asp:sqldatasource id="CustomersSqlDataSource"
selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
runat="server">
</asp:sqldatasource>
</form>
</body>
</html>
Commenti
Quando la funzionalità di paging è abilitata (impostando la proprietà su true), utilizzare PageIndex la AllowPaging proprietà per determinare l'indice della pagina attualmente visualizzata. È anche possibile usare questa proprietà per modificare a livello di codice la pagina visualizzata.
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