DetailsViewPageEventHandler Delegate

Definition

Rappresenta il metodo che gestisce l'evento PageIndexChanging di un controllo DetailsView.Represents the method that handles the PageIndexChanging event of a DetailsView control.

public delegate void DetailsViewPageEventHandler(System::Object ^ sender, DetailsViewPageEventArgs ^ e);
public delegate void DetailsViewPageEventHandler(object sender, DetailsViewPageEventArgs e);
type DetailsViewPageEventHandler = delegate of obj * DetailsViewPageEventArgs -> unit
Public Delegate Sub DetailsViewPageEventHandler(sender As Object, e As DetailsViewPageEventArgs)

Parameters

sender
Object

Origine dell'evento.The source of the event.

e
DetailsViewPageEventArgs

Elemento DetailsViewPageEventArgs contenente i dati dell'evento.A DetailsViewPageEventArgs that contains the event data.

Inheritance
DetailsViewPageEventHandler

Examples

Nell'esempio di codice seguente viene illustrato come aggiungere a livello di codice un delegato DetailsViewPageEventHandler all'evento PageIndexChanging di un controllo DetailsView.The following code example demonstrates how to programmatically add a DetailsViewPageEventHandler delegate to the PageIndexChanging event of a DetailsView control.


<%@ 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 Page_Load(Object sender, EventArgs e)
  {

    // Create a new DetailsView object.
    DetailsView customerDetailsView = new DetailsView();

    // Set the DetailsView object's properties.
    customerDetailsView.ID = "CustomerDetailsView";
    customerDetailsView.DataSourceID = "DetailsViewSource";
    customerDetailsView.AutoGenerateRows = true;
    customerDetailsView.AutoGenerateEditButton = true;
    customerDetailsView.AllowPaging = true;
    customerDetailsView.DataKeyNames = new String[1] { "CustomerID" };
    customerDetailsView.PagerSettings.Position = PagerPosition.Bottom;

    // Programmatically register the event-handling methods
    // for the DetailsView control.
    customerDetailsView.PageIndexChanging += new DetailsViewPageEventHandler(this.CustomerDetailsView_PageIndexChanging);
    customerDetailsView.ModeChanging += new DetailsViewModeEventHandler(this.CustomerDetailsView_ModeChanging);
    
    // Add the DetailsView object to the Controls collection
    // of the PlaceHolder control.
    DetailsViewPlaceHolder.Controls.Add(customerDetailsView);

  }
  
  void CustomerDetailsView_PageIndexChanging(Object sender, DetailsViewPageEventArgs e)
  {
    // Use the sender parameter to access the DetailsView control
    // that raised the event.
    DetailsView customerDetailsView = (DetailsView)sender;

    // Cancel the paging operation if the DetailsView control 
    // in edit mode.
    if (customerDetailsView.CurrentMode == DetailsViewMode.Edit)
    {
      e.Cancel = true;
      
      // Display an error message.
      int newPage = e.NewPageIndex + 1;
      MessageLabel.Text = "Please update the current record before to moving to page " + 
        newPage.ToString() + ".";
    }
  }

  void CustomerDetailsView_ModeChanging(Object sender, DetailsViewModeEventArgs e)
  {
    // Clear the message label when the user changes mode.
    MessageLabel.Text = "";
  }
  
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>DetailsViewPageEventHandler Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>DetailsViewPageEventHandler Example</h3>
                               
        <!-- Use a PlaceHolder control as the container for the -->
        <!-- dynamically generated DetailsView control.         -->       
        <asp:placeholder id="DetailsViewPlaceHolder"
          runat="server"/>
          
        <br/><br/>
        
        <asp:label id="MessageLabel"
          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"
          selectcommand="Select [CustomerID], [CompanyName], [Address], 
            [City], [PostalCode], [Country] From [Customers]"
          updatecommand="Update [Customers] Set 
          [CompanyName]=@CompanyName, [Address]=@Address, 
          [City]=@City, [PostalCode]=@PostalCode, 
          [Country]=@Country 
          Where [CustomerID]=@CustomerID"
          connectionstring=
          "<%$ ConnectionStrings:NorthWindConnectionString%>" 
          runat="server"/>
            
      </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 Page_Load(ByVal sender As Object, ByVal e As EventArgs)

    ' Create a new DetailsView object.
    Dim customerDetailsView As New DetailsView()

    ' Set the DetailsView object's properties.
    customerDetailsView.ID = "CustomerDetailsView"
    customerDetailsView.DataSourceID = "DetailsViewSource"
    customerDetailsView.AutoGenerateRows = True
    customerDetailsView.AutoGenerateEditButton = True
    customerDetailsView.AllowPaging = true
    customerDetailsView.PagerSettings.Position = PagerPosition.Bottom

    Dim keyArray() As String = {"CustomerID"}
    customerDetailsView.DataKeyNames = keyArray
       
    ' Programmatically register the event-handling methods
    ' for the DetailsView control.
    AddHandler customerDetailsView.PageIndexChanging, AddressOf CustomerDetailsView_PageIndexChanging
    AddHandler customerDetailsView.ModeChanging, AddressOf CustomerDetailsView_ModeChanging
    
    ' Add the DetailsView object to the Controls collection
    ' of the PlaceHolder control.
    DetailsViewPlaceHolder.Controls.Add(customerDetailsView)

  End Sub
  
  Sub CustomerDetailsView_PageIndexChanging(ByVal sender As Object, ByVal e As DetailsViewPageEventArgs)
  
    ' Use the sender parameter to access the DetailsView control
    ' that raised the event.
    Dim customerDetailsView As DetailsView = CType(sender, DetailsView)

    ' Cancel the paging operation if the DetailsView control 
    ' in edit mode.
    If customerDetailsView.CurrentMode = DetailsViewMode.Edit Then
    
      e.Cancel = True
      
      ' Display an error message.
      Dim newPage As Integer = e.NewPageIndex + 1
      MessageLabel.Text = "Please update the current record before to moving to page " & _
        newPage.ToString() & "."
    
    End If
      
  End Sub

  Sub CustomerDetailsView_ModeChanging(ByVal sender As Object, ByVal e As DetailsViewModeEventArgs)
  
    ' Clear the message label when the user changes mode.
    MessageLabel.Text = ""
  
  End Sub
  
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>DetailsViewPageEventHandler Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>DetailsViewPageEventHandler Example</h3>
                               
        <!-- Use a PlaceHolder control as the container for the -->
        <!-- dynamically generated DetailsView control.         -->       
        <asp:placeholder id="DetailsViewPlaceHolder"
          runat="server"/>
          
        <br/><br/>
        
        <asp:label id="MessageLabel"
          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"
          selectcommand="Select [CustomerID], [CompanyName], [Address], 
            [City], [PostalCode], [Country] From [Customers]"
          updatecommand="Update [Customers] Set 
          [CompanyName]=@CompanyName, [Address]=@Address, 
          [City]=@City, [PostalCode]=@PostalCode, 
          [Country]=@Country 
          Where [CustomerID]=@CustomerID"
          connectionstring=
          "<%$ ConnectionStrings:NorthWindConnectionString%>" 
          runat="server"/>
            
      </form>
  </body>
</html>

Nell'esempio di codice riportato di seguito viene illustrato come aggiungere in modo dichiarativo un delegato DetailsViewPageEventHandler all'evento PageIndexChanging di un controllo DetailsView.The following code example demonstrates how to declaratively add a DetailsViewPageEventHandler delegate to the PageIndexChanging event of a DetailsView control.


<%@ 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 CustomerDetailsView_PageIndexChanging(Object sender, DetailsViewPageEventArgs e)
  {
    // Cancel the paging operation if the DetailsView control 
    // in edit mode.
    if (CustomerDetailsView.CurrentMode == DetailsViewMode.Edit)
    {
      e.Cancel = true;
      
      // Display an error message.
      int newPage = e.NewPageIndex + 1;
      MessageLabel.Text = "Please update the current record before to moving to page " + 
        newPage.ToString() + ".";
    }
  }

  void CustomerDetailsView_ModeChanging(Object sender, DetailsViewModeEventArgs e)
  {
    // Clear the message label when the user changes mode.
    MessageLabel.Text = "";
  }
  
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>DetailsViewPageEventHandler Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>DetailsViewPageEventHandler Example</h3>
                       
        <asp:detailsview id="CustomerDetailsView"
          datasourceid="DetailsViewSource"
          autogeneraterows="true"
          autogenerateeditbutton="true"
          datakeynames="CustomerID"  
          allowpaging="true"
          onpageindexchanging="CustomerDetailsView_PageIndexChanging" 
          onmodechanging="CustomerDetailsView_ModeChanging"
          runat="server">
            
          <pagersettings position="Bottom"/> 
                    
        </asp:detailsview>
        
        <br/>
        
        <asp:label id="MessageLabel"
          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"
          selectcommand="Select [CustomerID], [CompanyName], [Address], 
            [City], [PostalCode], [Country] From [Customers]"
          updatecommand="Update [Customers] Set 
          [CompanyName]=@CompanyName, [Address]=@Address, 
          [City]=@City, [PostalCode]=@PostalCode, 
          [Country]=@Country 
          Where [CustomerID]=@CustomerID"
          connectionstring=
          "<%$ ConnectionStrings:NorthWindConnectionString%>" 
          runat="server"/>
            
      </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 CustomerDetailsView_PageIndexChanging(ByVal sender As Object, ByVal e As DetailsViewPageEventArgs) Handles CustomerDetailsView.PageIndexChanging
  
    ' Cancel the paging operation if the DetailsView control 
    ' in edit mode.
    If CustomerDetailsView.CurrentMode = DetailsViewMode.Edit Then
    
      e.Cancel = True
      
      ' Display an error message.
      Dim newPage As Integer = e.NewPageIndex + 1
      MessageLabel.Text = "Please update the current record before to moving to page " & _
        newPage.ToString() & "."
    
    End If
      
  End Sub

  Sub CustomerDetailsView_ModeChanging(ByVal sender As Object, ByVal e As DetailsViewModeEventArgs) Handles CustomerDetailsView.ModeChanging
  
    ' Clear the message label when the user changes mode.
    MessageLabel.Text = ""
      
  End Sub
  
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>DetailsViewPageEventHandler Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>DetailsViewPageEventHandler Example</h3>
                       
        <asp:detailsview id="CustomerDetailsView"
          datasourceid="DetailsViewSource"
          autogeneraterows="true"
          autogenerateeditbutton="true"
          datakeynames="CustomerID"   
          allowpaging="true"
          runat="server">
            
          <pagersettings position="Bottom"/> 
                    
        </asp:detailsview>
        
        <br/>
        
        <asp:label id="MessageLabel"
          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"
          selectcommand="Select [CustomerID], [CompanyName], [Address], 
            [City], [PostalCode], [Country] From [Customers]"
          updatecommand="Update [Customers] Set 
          [CompanyName]=@CompanyName, [Address]=@Address, 
          [City]=@City, [PostalCode]=@PostalCode, 
          [Country]=@Country 
          Where [CustomerID]=@CustomerID"
          connectionstring=
          "<%$ ConnectionStrings:NorthWindConnectionString%>" 
          runat="server"/>
            
      </form>
  </body>
</html>

Remarks

Il controllo DetailsView genera l'evento PageIndexChanging quando si fa clic su un pulsante del cercapersone, ovvero un pulsante con la relativa proprietà CommandName impostata su "Page", all'interno del controllo, ma prima che il controllo DetailsView 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.

Note

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

Quando si crea un delegato DetailsViewPageEventHandler, si identifica il metodo che gestirà l'evento.When you create a DetailsViewPageEventHandler delegate, you identify the method that will handle the event. Per associare l'evento al gestore eventi in uso, aggiungere all'evento un'istanza del delegato.To associate the event with your event handler, add an instance of the delegate to the event. Il gestore eventi viene chiamato ogni volta che si verifica l'evento, a meno che non venga rimosso il delegato.The event handler is called whenever the event occurs, unless you remove the delegate. Per ulteriori informazioni sui delegati del gestore eventi, vedere gestione e generazione di eventi.For more information about event-handler delegates, see Handling and Raising Events.

Extension Methods

GetMethodInfo(Delegate)

Ottiene un oggetto che rappresenta il metodo rappresentato dal delegato specificato.Gets an object that represents the method represented by the specified delegate.

Applies to

See also