DetailsView.ItemDeleting Händelse
Definition
Viktigt
En del information gäller för förhandsversionen av en produkt och kan komma att ändras avsevärt innan produkten blir allmänt tillgänglig. Microsoft lämnar inga garantier, uttryckliga eller underförstådda, avseende informationen som visas här.
Inträffar när knappen Ta bort i en DetailsView kontroll klickas, men före borttagningsåtgärden.
public:
event System::Web::UI::WebControls::DetailsViewDeleteEventHandler ^ ItemDeleting;public event System.Web.UI.WebControls.DetailsViewDeleteEventHandler ItemDeleting;member this.ItemDeleting : System.Web.UI.WebControls.DetailsViewDeleteEventHandler Public Custom Event ItemDeleting As DetailsViewDeleteEventHandler Händelsetyp
Exempel
Följande kodexempel visar hur du använder ItemDeleting händelsen för att avbryta borttagningsåtgärden om användaren försöker ta bort det sista objektet från DetailsView kontrollen.
<%@ 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_ItemDeleting(Object sender, DetailsViewDeleteEventArgs e)
{
// Cancel the delete operation if the user attempts to delete the last
// record from the data source.
if (CustomerDetailView.DataItemCount <= 1)
{
e.Cancel = true;
MessageLabel.Text = "You must keep at least one store.";
}
else
{
MessageLabel.Text = "";
}
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>DetailsView ItemDeleting Example</title>
</head>
<body>
<form id="Form1" runat="server">
<h3>DetailsView ItemDeleting Example</h3>
<asp:detailsview id="CustomerDetailView"
datasourceid="DetailsViewSource"
datakeynames="CustomerID"
autogeneratedeletebutton="true"
autogeneraterows="true"
allowpaging="true"
onitemdeleting="CustomerDetailView_ItemDeleting"
runat="server">
<fieldheaderstyle backcolor="Navy"
forecolor="White"/>
</asp:detailsview>
<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" 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]"
DeleteCommand="DELETE FROM [Customers] WHERE [CustomerID] = @CustomerID" >
</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_ItemDeleting(ByVal sender As Object, ByVal e As DetailsViewDeleteEventArgs)
' Cancel the delete operation if the user attempts to delete the last
' record from the data source.
If (CustomerDetailView.DataItemCount <= 1) Then
e.Cancel = True
MessageLabel.Text = "You must keep at least one store."
Else
MessageLabel.Text = ""
End If
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>DetailsView ItemDeleting Example</title>
</head>
<body>
<form id="Form1" runat="server">
<h3>DetailsView ItemDeleting Example</h3>
<asp:detailsview id="CustomerDetailView"
datasourceid="DetailsViewSource"
datakeynames="CustomerID"
autogeneratedeletebutton="true"
autogeneraterows="true"
allowpaging="true"
onitemdeleting="CustomerDetailView_ItemDeleting"
runat="server">
<fieldheaderstyle backcolor="Navy"
forecolor="White"/>
</asp:detailsview>
<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" 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]"
DeleteCommand="DELETE FROM [Customers] WHERE [CustomerID] = @CustomerID" >
</asp:SqlDataSource>
</form>
</body>
</html>
Kommentarer
Händelsen ItemDeleting utlöses när knappen Ta bort i DetailsView kontrollen klickas, men före borttagningsåtgärden. På så sätt kan du ange en händelsehanterare som utför en anpassad rutin, till exempel avbryta borttagningsåtgärden, när den här händelsen inträffar.
Ett DetailsViewDeleteEventArgs objekt skickas till händelsehanteraren, vilket gör att du kan fastställa indexet för posten som tas bort och ange att borttagningsåtgärden ska avbrytas. Om du vill avbryta borttagningsåtgärden anger du egenskapen Cancel till true. Du kan också ändra samlingarna Keys och Values om det behövs innan värdena skickas till datakällan.
Mer information om hur du hanterar händelser finns i Hantera och höja händelser.
