ObjectDataSourceView.OnDeleted(ObjectDataSourceStatusEventArgs) ObjectDataSourceView.OnDeleted(ObjectDataSourceStatusEventArgs) ObjectDataSourceView.OnDeleted(ObjectDataSourceStatusEventArgs) ObjectDataSourceView.OnDeleted(ObjectDataSourceStatusEventArgs) Method

Definizione

Genera l'evento Deleted quando il l'oggetto ObjectDataSourceView completa un'operazione di eliminazione.Raises the Deleted event after the ObjectDataSourceView object has completed a delete operation.

protected:
 virtual void OnDeleted(System::Web::UI::WebControls::ObjectDataSourceStatusEventArgs ^ e);
protected virtual void OnDeleted (System.Web.UI.WebControls.ObjectDataSourceStatusEventArgs e);
abstract member OnDeleted : System.Web.UI.WebControls.ObjectDataSourceStatusEventArgs -> unit
override this.OnDeleted : System.Web.UI.WebControls.ObjectDataSourceStatusEventArgs -> unit
Protected Overridable Sub OnDeleted (e As ObjectDataSourceStatusEventArgs)

Parametri

Esempi

Nell'esempio di codice riportato di seguito viene illustrato ObjectDataSource come utilizzare un controllo con un oggetto GridView business e un controllo per eliminare i dati.The following code example demonstrates how to use an ObjectDataSource control with a business object and a GridView control to delete data. Inizialmente viene visualizzato un set di tutti i dipendenti, utilizzando il metodo specificato SelectMethod dalla proprietà per EmployeeLogic recuperare i dati dall'oggetto. GridViewThe GridView initially displays a set of all employees, using the method that is specified by the SelectMethod property to retrieve the data from the EmployeeLogic object. Poiché la AutoGenerateDeleteButton proprietà è impostata su true, il GridView controllo Visualizza automaticamente un pulsante Elimina .Because the AutoGenerateDeleteButton property is set to true, the GridView control automatically displays a Delete button.

Se si fa clic sul pulsante Elimina , Delete l'operazione viene eseguita utilizzando il metodo specificato dalla DeleteMethod proprietà e DeleteParameters tutti i parametri specificati nella raccolta.If you click the Delete button, the Delete operation is performed using the method that is specified by the DeleteMethod property and any parameters that are specified in the DeleteParameters collection. In questo esempio di codice vengono eseguiti anche alcuni passaggi di pre-elaborazione e post-elaborazione.In this code example, some preprocessing and post-processing steps are also performed. Il NorthwindEmployeeDeleting delegato viene chiamato per gestire l' Deleting evento prima dell' Delete esecuzione dell'operazione e il NorthwindEmployeeDeleted delegato viene chiamato per gestire l' Deleted evento dopo il completamento Delete dell'operazione, fino a eseguire una gestione delle eccezioni.The NorthwindEmployeeDeleting delegate is called to handle the Deleting event before the Delete operation is performed, and the NorthwindEmployeeDeleted delegate is called to handle the Deleted event after the Delete operation has completed, to perform an exception handling. In questo esempio, se viene NorthwindDataException generata un'eccezione, questa viene gestita da questo delegato.In this example, if a NorthwindDataException is thrown, it is handled by this delegate.

Per esaminare l'implementazione dell'oggetto EmployeeLogic business di livello intermedio utilizzato in questo esempio di codice, ObjectDataSourceStatusEventArgsvedere.To examine the implementation of the EmployeeLogic middle-tier business object that this code example uses, see ObjectDataSourceStatusEventArgs.

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS" Assembly="Samples.AspNet.CS" %>
<%@ Import namespace="Samples.AspNet.CS" %>
<%@ 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">
private void NorthwindEmployeeDeleting(object source, ObjectDataSourceMethodEventArgs e)
{
  // The GridView passes the ID of the employee
  // to be deleted. However, the buisiness object, EmployeeLogic,
  // requires a NorthwindEmployee parameter, named "ne". Create
  // it now and add it to the parameters collection.
  IDictionary paramsFromPage = e.InputParameters;
  if (paramsFromPage["EmpID"] != null) {
    NorthwindEmployee ne
      = new NorthwindEmployee( Int32.Parse(paramsFromPage["EmpID"].ToString()));
    // Remove the old EmpID parameter.
    paramsFromPage.Clear();
    paramsFromPage.Add("ne", ne);
  }
}

private void NorthwindEmployeeDeleted(object source, ObjectDataSourceStatusEventArgs e)
{
  // Handle the Exception if it is a NorthwindDataException
  if (e.Exception != null)
  {

    // Handle the specific exception type. The ObjectDataSource wraps
    // any Exceptions in a TargetInvokationException wrapper, so
    // check the InnerException property for expected Exception types.
    if (e.Exception.InnerException is NorthwindDataException)
    {
      Label1.Text = e.Exception.InnerException.Message;
      // Because the exception is handled, there is
      // no reason to throw it.
      e.ExceptionHandled = true;
    }
  }
}

</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head>
    <title>ObjectDataSource - C# Example</title>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">

        <asp:gridview
          id="GridView1"
          runat="server"
          datasourceid="ObjectDataSource1"
          autogeneratedeletebutton="true"
          autogeneratecolumns="false"
          datakeynames="EmpID">
          <columns>
            <asp:boundfield headertext="EmpID" datafield="EmpID" />
            <asp:boundfield headertext="First Name" datafield="FirstName" />
            <asp:boundfield headertext="Last Name" datafield="LastName" />
          </columns>
        </asp:gridview>

        <asp:objectdatasource
          id="ObjectDataSource1"
          runat="server"
          selectmethod="GetAllEmployees"
          deletemethod="DeleteEmployee"
          ondeleting="NorthwindEmployeeDeleting"
          ondeleted="NorthwindEmployeeDeleted"
          typename="Samples.AspNet.CS.EmployeeLogic">
          <deleteparameters>
            <asp:parameter name="EmpID" type="Int32" />
          </deleteparameters>
        </asp:objectdatasource>

        <asp:label id="Label1" runat="server" />

    </form>
  </body>
</html>
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB" Assembly="Samples.AspNet.VB" %>
<%@ Import namespace="Samples.AspNet.VB" %>
<%@ 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">
' Called before a Delete operation.
    Private Sub NorthwindEmployeeDeleting(ByVal source As Object, ByVal e As ObjectDataSourceMethodEventArgs)

        ' The GridView passes the ID of the employee
        ' to be deleted. However, the business object, EmployeeLogic,
        ' requires a NorthwindEmployee parameter, named "ne". Create
        ' it now and add it to the parameters collection.
        Dim paramsFromPage As IDictionary = e.InputParameters
  
        If Not paramsFromPage("EmpID") Is Nothing Then
    
            Dim ne As New NorthwindEmployee(paramsFromPage("EmpID").ToString())
            ' Remove the old EmpID parameter.
            paramsFromPage.Clear()
            paramsFromPage.Add("ne", ne)
    
    
        End If
    End Sub ' NorthwindEmployeeDeleting

    ' Called after a Delete operation.
    Private Sub NorthwindEmployeeDeleted(ByVal source As Object, ByVal e As ObjectDataSourceStatusEventArgs)
        ' Handle the Exception if it is a NorthwindDataException.
        If Not e.Exception Is Nothing Then

            ' Handle the specific exception type. The ObjectDataSource wraps
            ' any Exceptions in a TargetInvokationException wrapper, so
            ' check the InnerException property for the expected Exception types.
            If e.Exception.InnerException.GetType().Equals(GetType(NorthwindDataException)) Then

                Label1.Text = e.Exception.InnerException.Message
                ' Because the exception is handled, there is
                ' no reason to throw it.
                e.ExceptionHandled = True
      
            End If
        End If
    End Sub ' NorthwindEmployeeDeleted
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head>
    <title>ObjectDataSource - VB Example</title>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">

        <asp:gridview
          id="GridView1"
          runat="server"
          datasourceid="ObjectDataSource1"
          autogeneratedeletebutton="true"
          autogeneratecolumns="false"
          datakeynames="EmpID">
          <columns>
            <asp:boundfield headertext="EmpID" datafield="EmpID" />
            <asp:boundfield headertext="First Name" datafield="FirstName" />
            <asp:boundfield headertext="Last Name" datafield="LastName" />
          </columns>
        </asp:gridview>

        <asp:objectdatasource
          id="ObjectDataSource1"
          runat="server"
          selectmethod="GetAllEmployees"
          deletemethod="DeleteEmployee"
          ondeleting="NorthwindEmployeeDeleting"
          ondeleted="NorthwindEmployeeDeleted"
          typename="Samples.AspNet.VB.EmployeeLogic">
          <deleteparameters>
            <asp:parameter name="EmpID" type="Int32" />
          </deleteparameters>
        </asp:objectdatasource>

        <asp:label id="Label1" runat="server" />

    </form>
  </body>
</html>

Commenti

Quando viene generato un evento, il gestore dell'evento viene richiamato tramite un delegato.Raising an event invokes the event handler through a delegate. 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.

Il metodo OnDeleted consente inoltre alle classi derivate di gestire l'evento senza associare un delegato.The OnDeleted method also allows derived classes to handle the event without attaching a delegate. È la tecnica consigliata per la gestione dell'evento in una classe derivata.This is the preferred technique for handling the event in a derived class.

Note per gli eredi

Quando si esegue l' OnDeleted(ObjectDataSourceStatusEventArgs) override di in una classe derivata, assicurarsi di chiamare OnDeleted(ObjectDataSourceStatusEventArgs) il metodo per la classe di base in modo che i delegati registrati ricevano l'evento.When overriding the OnDeleted(ObjectDataSourceStatusEventArgs) in a derived class, be sure to call the OnDeleted(ObjectDataSourceStatusEventArgs) method for the base class so that registered delegates receive the event.

Si applica a

Vedi anche