DetailsViewDeletedEventHandler Delegato
Definizione
Importante
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Rappresenta il metodo che gestisce l'evento ItemDeleted di un controllo DetailsView.
public delegate void DetailsViewDeletedEventHandler(System::Object ^ sender, DetailsViewDeletedEventArgs ^ e);public delegate void DetailsViewDeletedEventHandler(object sender, DetailsViewDeletedEventArgs e);type DetailsViewDeletedEventHandler = delegate of obj * DetailsViewDeletedEventArgs -> unitPublic Delegate Sub DetailsViewDeletedEventHandler(sender As Object, e As DetailsViewDeletedEventArgs)Parametri
- sender
- Object
Origine dell'evento.
Oggetto DetailsViewDeletedEventArgs che contiene i dati dell'evento.
Esempio
Nell'esempio di codice seguente viene illustrato come aggiungere un DetailsViewDeletedEventHandler delegato a livello di codice all'evento ItemDeleted di un DetailsView controllo .
<%@ page language="C#"%>
<!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 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.AutoGenerateDeleteButton = true;
customerDetailsView.AllowPaging = true;
customerDetailsView.PagerSettings.Mode =
PagerButtons.NextPrevious;
customerDetailsView.DataKeyNames = new String[1] { "CustomerID" };
// Programmatically register the event-handling method
// for the ItemDeleted event of a DetailsView control.
customerDetailsView.ItemDeleted +=
new DetailsViewDeletedEventHandler(
this.CustomerDetailView_ItemDeleted);
// Add the DetailsView object to the Controls collection
// of the PlaceHolder control.
DetailsViewPlaceHolder.Controls.Add(customerDetailsView);
}
void CustomerDetailView_ItemDeleted(Object sender,
DetailsViewDeletedEventArgs e)
{
// Use the Exception property to determine whether an exception
// occurred during the delete operation.
if (e.Exception == null)
{
// Use the AffectedRows property to determine the numbers of
// rows affected by the delete operation.
if (e.AffectedRows == 1)
{
MessageLabel.Text = e.AffectedRows.ToString()
+ " record deleted successfully.";
}
else
{
MessageLabel.Text = e.AffectedRows.ToString()
+ " records deleted successfully.";
}
}
else
{
// Insert the code to handle the exception.
MessageLabel.Text = e.Exception.Message;
// Use the ExceptionHandled property to indicate that the
// exception is already handled.
e.ExceptionHandled = true;
}
}
</script>
<head runat="server">
<title>DetailsViewDeletedEventHandler Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>DetailsViewDeletedEventHandler 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]"
deletecommand="Delete [Customers]
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">
<html xmlns="http://www.w3.org/1999/xhtml" >
<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.AutoGenerateDeleteButton = True
customerDetailsView.AllowPaging = True
customerDetailsView.PagerSettings.Mode = _
PagerButtons.NextPrevious
Dim keyArray() As String = {"CustomerID"}
customerDetailsView.DataKeyNames = keyArray
' Programmatically register the event-handling method
' for the ItemDeleted event of a DetailsView control.
AddHandler customerDetailsView.ItemDeleted, _
AddressOf CustomerDetailView_ItemDeleted
' Add the DetailsView object to the Controls collection
' of the PlaceHolder control.
DetailsViewPlaceHolder.Controls.Add(customerDetailsView)
End Sub
Sub CustomerDetailView_ItemDeleted(ByVal sender As Object, _
ByVal e As DetailsViewDeletedEventArgs)
' Use the Exception property to determine whether an exception
' occurred during the delete operation.
If e.Exception Is Nothing Then
' Use the AffectedRows property to determine the numbers of
' rows affected by the delete operation.
If e.AffectedRows = 1 Then
MessageLabel.Text = e.AffectedRows.ToString() _
& " record deleted successfully."
Else
MessageLabel.Text = e.AffectedRows.ToString() _
& " records deleted successfully."
End If
Else
' Insert the code to handle the exception.
MessageLabel.Text = e.Exception.Message
' Use the ExceptionHandled property to indicate that the
' exception is already handled.
e.ExceptionHandled = True
End If
End Sub
</script>
<head runat="server">
<title>DetailsViewDeletedEventHandler Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>DetailsViewDeletedEventHandler 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]"
deletecommand="Delete [Customers]
Where [CustomerID]=@CustomerID"
connectionstring=
"<%$ ConnectionStrings:NorthWindConnectionString%>"
runat="server"/>
</form>
</body>
</html>
Nell'esempio di codice seguente viene illustrato come aggiungere in modo dichiarativo un DetailsViewDeletedEventHandler delegato all'evento ItemDeleted di un DetailsView controllo .
<%@ page language="C#"%>
<!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 runat="server">
void CustomerDetailView_ItemDeleted(Object sender,
DetailsViewDeletedEventArgs e)
{
// Use the Exception property to determine whether an exception
// occurred during the delete operation.
if (e.Exception == null)
{
// Use the AffectedRows property to determine the numbers of
// rows affected by the delete operation.
if (e.AffectedRows == 1)
{
MessageLabel.Text = e.AffectedRows.ToString()
+ " record deleted successfully.";
}
else
{
MessageLabel.Text = e.AffectedRows.ToString()
+ " records deleted successfully.";
}
}
else
{
// Insert the code to handle the exception.
MessageLabel.Text = e.Exception.Message;
// Use the ExceptionHandled property to indicate that the
// exception is already handled.
e.ExceptionHandled = true;
}
}
</script>
<head runat="server">
<title>DetailsViewDeletedEventHandler Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>DetailsViewDeletedEventHandler Example</h3>
<asp:detailsview id="CustomerDetailsView"
datasourceid="DetailsViewSource"
autogeneraterows="true"
autogeneratedeletebutton="true"
allowpaging="true"
datakeynames="CustomerID"
runat="server">
<pagersettings mode="NextPrevious"/>
</asp:detailsview>
<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]"
deletecommand="Delete [Customers]
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">
<html xmlns="http://www.w3.org/1999/xhtml" >
<script runat="server">
Sub CustomerDetailView_ItemDeleted(ByVal sender As Object, _
ByVal e As DetailsViewDeletedEventArgs)
' Use the Exception property to determine whether an exception
' occurred during the delete operation.
If e.Exception Is Nothing Then
' Use the AffectedRows property to determine the numbers of
' rows affected by the delete operation.
If e.AffectedRows = 1 Then
MessageLabel.Text = e.AffectedRows.ToString() _
& " record deleted successfully."
Else
MessageLabel.Text = e.AffectedRows.ToString() _
& " records deleted successfully."
End If
Else
' Insert the code to handle the exception.
MessageLabel.Text = e.Exception.Message
' Use the ExceptionHandled property to indicate that the
' exception is already handled.
e.ExceptionHandled = True
End If
End Sub
</script>
<head runat="server">
<title>DetailsViewDeletedEventHandler Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>DetailsViewDeletedEventHandler Example</h3>
<asp:detailsview id="CustomerDetailsView"
datasourceid="DetailsViewSource"
autogeneraterows="true"
autogeneratedeletebutton="true"
allowpaging="true"
datakeynames="CustomerID"
runat="server">
<pagersettings mode="NextPrevious"/>
</asp:detailsview>
<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]"
deletecommand="Delete [Customers]
Where [CustomerID]=@CustomerID"
connectionstring=
"<%$ ConnectionStrings:NorthWindConnectionString%>"
runat="server"/>
</form>
</body>
</html>
Commenti
Il DetailsView controllo genera l'evento ItemDeleted quando si fa clic su un pulsante Elimina (un pulsante con la relativa CommandName proprietà impostata su "Elimina") all'interno del controllo, ma dopo che il DetailsView controllo elimina il record. In questo modo è possibile fornire un gestore eventi che esegue una routine personalizzata, ad esempio il controllo dei risultati di un'operazione di eliminazione, ogni volta che si verifica questo evento.
Quando si crea un delegato DetailsViewDeletedEventHandler, si identifica il metodo che gestirà l'evento. Per associare l'evento al gestore eventi in uso, aggiungere all'evento un'istanza del delegato. Il gestore eventi viene chiamato ogni volta che si verifica l'evento, a meno che non venga rimosso il delegato. Per altre informazioni sui delegati del gestore eventi, vedere Gestione e generazione di eventi.
Metodi di estensione
| GetMethodInfo(Delegate) |
Ottiene un oggetto che rappresenta il metodo rappresentato dal delegato specificato. |
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