GridViewDeletedEventArgs.AffectedRows Egenskap
Definition
Viktigt
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Hämtar antalet rader som påverkas av borttagningsåtgärden.
public:
property int AffectedRows { int get(); };public int AffectedRows { get; }member this.AffectedRows : intPublic ReadOnly Property AffectedRows As IntegerEgenskapsvärde
Antalet rader som påverkas av borttagningsåtgärden.
Exempel
I följande exempel visas hur du använder AffectedRows egenskapen för att verifiera att en post togs bort under borttagningen.
<%@ 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 CustomersGridView_RowDeleted(Object sender, GridViewDeletedEventArgs 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 whether the
// record was deleted. Sometimes an error might occur that
// does not raise an exception, but prevents the delete
// operation from completing.
if (e.AffectedRows == 1)
{
Message.Text = "Record deleted successfully.";
}
else
{
Message.Text = "An error occurred during the delete operation.";
}
}
else
{
// Insert the code to handle the exception.
Message.Text = "An error occurred during the delete operation.";
// Use the ExceptionHandled property to indicate that the
// exception is already handled.
e.ExceptionHandled = true;
}
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>GridViewDeletedEventArgs Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>GridViewDeletedEventArgs Example</h3>
<asp:label id="Message"
forecolor="Red"
runat="server"/>
<br/>
<!-- The GridView control automatically sets the columns -->
<!-- specified in the datakeynames property as read-only. -->
<!-- No input controls are rendered for these columns in -->
<!-- edit mode. -->
<asp:gridview id="CustomersGridView"
datasourceid="CustomersSqlDataSource"
autogeneratecolumns="true"
autogeneratedeletebutton="true"
datakeynames="CustomerID"
onrowdeleted="CustomersGridView_RowDeleted"
runat="server">
</asp:gridview>
<!-- 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="CustomersSqlDataSource"
selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
deletecommand="Delete from Customers where CustomerID = @CustomerID"
connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
runat="server">
</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 CustomersGridView_RowDeleted(ByVal sender As Object, ByVal e As GridViewDeletedEventArgs)
' 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 whether the
' record was deleted. Sometimes an error might occur that
' does not raise an exception, but prevents the delete
' operation from completing.
If e.AffectedRows = 1 Then
Message.Text = "Record deleted successfully."
Else
Message.Text = "An error occurred during the delete operation."
End If
Else
' Insert the code to handle the exception.
Message.Text = "An error occurred during the delete operation."
' Use the ExceptionHandled property to indicate that the
' exception is already handled.
e.ExceptionHandled = True
End If
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>GridViewDeletedEventArgs Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>GridViewDeletedEventArgs Example</h3>
<asp:label id="Message"
forecolor="Red"
runat="server"/>
<br/>
<!-- The GridView control automatically sets the columns -->
<!-- specified in the datakeynames property as read-only. -->
<!-- No input controls are rendered for these columns in -->
<!-- edit mode. -->
<asp:gridview id="CustomersGridView"
datasourceid="CustomersSqlDataSource"
autogeneratecolumns="true"
autogeneratedeletebutton="true"
datakeynames="CustomerID"
onrowdeleted="CustomersGridView_RowDeleted"
runat="server">
</asp:gridview>
<!-- 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="CustomersSqlDataSource"
selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
deletecommand="Delete from Customers where CustomerID = @CustomerID"
connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
runat="server">
</asp:sqldatasource>
</form>
</body>
</html>
Kommentarer
Använd egenskapen AffectedRows för att fastställa antalet poster som påverkas av borttagningsåtgärden. Den här egenskapen används ofta för att verifiera att rätt antal poster har tagits bort i följande situationer:
Kontrollera att endast en enskild post har tagits bort. Ibland kan en felaktigt skriven borttagningsuttryck ta bort flera poster.
Kontrollera att en post har tagits bort när ett fel inträffar under borttagningsåtgärden som inte skapar ett undantag.
Kontrollera att en post togs bort när en datakällaskontroll som stöder optimistisk samtidighet (till exempel SqlDataSource kontrollerna och ObjectDataSource ) har dess ConflictDetection egenskap inställd på
ConflictOptions.CompareAllValuesuppräkningsvärdet. Enligt den här inställningen kanske inte en post som har ändrats av en annan användare samtidigt tas bort.
