DetailsView.PageIndexChanging Evento

Definizione

Si verifica quando il valore della proprietà PageIndex cambia prima di un'operazione di spostamento.Occurs when the value of the PageIndex property changes before a paging operation.

public:
 event System::Web::UI::WebControls::DetailsViewPageEventHandler ^ PageIndexChanging;
public event System.Web.UI.WebControls.DetailsViewPageEventHandler PageIndexChanging;
member this.PageIndexChanging : System.Web.UI.WebControls.DetailsViewPageEventHandler 
Public Custom Event PageIndexChanging As DetailsViewPageEventHandler 

Esempi

Nell'esempio di codice riportato di seguito viene illustrato PageIndexChanging come utilizzare l'evento per annullare un'operazione di paging.The following code example demonstrates how to use the PageIndexChanging event to cancel a paging operation.


<%@ 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">


    void CustomerDetailView_ItemCommand(Object sender, 
      DetailsViewCommandEventArgs e)
    {
        // Clear the error message if the user cancels the edit 
        // operation.
        if (e.CommandName == "Cancel")
        {
            ErrorMessageLabel.Text = "";
        }
    }

    protected void CustomerDetailView_PageIndexChanging(
      object sender, DetailsViewPageEventArgs e)
    {
        // Cancel the paging operation if the user tries to 
        // navigate to another record while in edit mode.
        if (CustomerDetailView.CurrentMode == DetailsViewMode.Edit)
        {
            e.Cancel = true;
            // Display an error message.
            ErrorMessageLabel.Text = 
              "You cannot navigate to another record while in edit mode.";
        }

    }
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>
            DetailsView CurrentMode Example</title>
</head>
<body>
    <form id="Form1" runat="server">
        <h3>
            DetailsView CurrentMode Example</h3>
        <asp:DetailsView ID="CustomerDetailView" 
          DataSourceID="DetailsViewSource" 
          AutoGenerateRows="true"
          AutoGenerateEditButton="true" 
          DataKeyNames="CustomerID" 
          GridLines="Both" 
          AllowPaging="true"
          OnItemCommand="CustomerDetailView_ItemCommand" 
          runat="server" 
          OnPageIndexChanging="CustomerDetailView_PageIndexChanging">
          
          <HeaderStyle BackColor="Navy" ForeColor="White" />
        </asp:DetailsView>
        
        <br />
        
        <asp:Label ID="ErrorMessageLabel" 
          ForeColor="Red" runat="server" />
        
        <!-- 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="DetailsViewSource" runat="server" 
          ConnectionString=
            "<%$ ConnectionStrings:NorthWindConnectionString%>"
          InsertCommand="INSERT INTO [Customers]([CustomerID],
            [CompanyName], [Address], [City], [PostalCode], [Country]) 
            VALUES (@CustomerID, @CompanyName, @Address, @City, 
            @PostalCode, @Country)"
          SelectCommand="Select [CustomerID], [CompanyName], 
            [Address], [City], [PostalCode], [Country] From 
            [Customers]">
        </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">


    Sub CustomerDetailView_ItemCommand(ByVal sender As Object, _
      ByVal e As DetailsViewCommandEventArgs)
        ' Clear the error message if the user cancels the edit 
        ' operation.
        If e.CommandName = "Cancel" Then
            ErrorMessageLabel.Text = ""
        End If
    End Sub

    Protected Sub CustomerDetailView_PageIndexChanging( _
    ByVal sender As Object, ByVal e As DetailsViewPageEventArgs)
        ' Cancel the paging operation if the user tries to navigate 
        ' to another record while in edit mode.
        If CustomerDetailView.CurrentMode = DetailsViewMode.Edit Then
            e.Cancel = True
            ' Display an error message.
            ErrorMessageLabel.Text = _
                "You cannot navigate to another record while in edit mode."
        End If
    End Sub
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>
            DetailsView CurrentMode Example</title>
</head>
<body>
    <form id="Form1" runat="server">
        <h3>
            DetailsView CurrentMode Example</h3>
        <asp:DetailsView ID="CustomerDetailView" 
          DataSourceID="DetailsViewSource" 
          AutoGenerateRows="true"
          AutoGenerateEditButton="true" 
          DataKeyNames="CustomerID" 
          GridLines="Both" 
          AllowPaging="true"
          OnItemCommand="CustomerDetailView_ItemCommand" 
          runat="server" 
          OnPageIndexChanging="CustomerDetailView_PageIndexChanging">
          
          <HeaderStyle BackColor="Navy" ForeColor="White" />
        </asp:DetailsView>
        
        <br />
        
        <asp:Label ID="ErrorMessageLabel" 
          ForeColor="Red" runat="server" />
        
        <!-- 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="DetailsViewSource" runat="server" 
          ConnectionString=
            "<%$ ConnectionStrings:NorthWindConnectionString%>"
          InsertCommand="INSERT INTO [Customers]([CustomerID],
            [CompanyName], [Address], [City], [PostalCode], [Country]) 
            VALUES (@CustomerID, @CompanyName, @Address, @City, 
            @PostalCode, @Country)"

          SelectCommand="Select [CustomerID], [CompanyName], 
            [Address], [City], [PostalCode], [Country] From 
            [Customers]">
        </asp:SqlDataSource>
    </form>
</body>
</html>

Commenti

Il DetailsView controllo genera l' PageIndexChanging evento quando si fa clic su un pulsante del cercapersone CommandName , ovvero un pulsante con la relativa proprietà impostata su "Page", all'interno del DetailsView controllo, ma prima che il controllo gestisca l'operazione di paging.The DetailsView control raises the PageIndexChanging event when a pager button (a button with its CommandName property set to "Page") within the control is clicked, but before the DetailsView control handles the paging operation. Questo consente di fornire un gestore eventi che esegue una routine personalizzata, ad esempio l'annullamento dell'operazione di paging, ogni volta che si verifica questo evento.This allows you to provide an event handler that performs a custom routine, such as canceling the paging operation, whenever this event occurs.

Nota

Questo evento non viene generato quando si imposta a livello di PageIndex codice la proprietà.This event is not raised when you programmatically set the PageIndex property.

I pulsanti di spostamento si trovano in genere nella riga del DetailsView cercapersone di un controllo.Pager buttons are usually located in the pager row of a DetailsView control.

Un DetailsViewPageEventArgs oggetto viene passato al gestore eventi, che consente di determinare l'indice della pagina selezionata dall'utente e di indicare che l'operazione di paging deve essere annullata.A DetailsViewPageEventArgs object is passed to the event handler, which allows you to determine the index of the page selected by the user and to indicate that the paging operation should be canceled. Per determinare l'indice della pagina selezionata dall'utente, utilizzare la NewPageIndex proprietà.To determine the index of the page selected by the user, use the NewPageIndex property. Per annullare l'operazione di paging, impostare Cancel la proprietà DetailsViewPageEventArgs dell'oggetto su true.To cancel the paging operation, set the Cancel property of the DetailsViewPageEventArgs object to true.

Per altre informazioni su come gestire gli eventi, vedere la gestione e generazione di eventi.For more information about how to handle events, see Handling and Raising Events.

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