UpdateSourceExceptionFilterCallback Delegate
Represents the method that handles exceptions that are thrown during the update of the binding source value. This must be used with the ExceptionValidationRule.
Assembly: PresentationFramework (in PresentationFramework.dll)
public delegate Object^ UpdateSourceExceptionFilterCallback( Object^ bindExpression, Exception^ exception )
Parameters
- bindExpression
- Type: System::Object
The object with the exception.
- exception
- Type: System::Exception
The exception encountered.
Return Value
Type: System::ObjectAn object that is typically one of the following:
Value | Description |
|---|---|
nullptr | To ignore any exceptions. The default behavior (if there is no UpdateSourceExceptionFilterCallback) is to create a ValidationError with the exception and adds it to the Validation::Errors collection of the bound element. |
Any object | To create a ValidationError object with the ErrorContent set to that object. The ValidationError object is added to Validation::Errors collection of the bound element. |
A ValidationError object | To set the BindingExpression or MultiBindingExpression object as the BindingInError. The ValidationError object is added to Validation::Errors collection of the bound element. |
If you have associated the ExceptionValidationRule with your Binding object you have the option to use the UpdateSourceExceptionFilter property to set this callback to provide custom logic for handling the exceptions. This callback is invoked whenever any exception is encountered when the binding engine updates the binding source value.
If an UpdateSourceExceptionFilter is not specified on the Binding, the binding engine creates a ValidationError with the exception and adds it to the Validation::Errors collection of the bound element.
The Text property of the following TextBox is data-bound to a source property Age3 that is of type int. The ExceptionValidationRule checks for exceptions that are thrown during the update of the source property (such as when the user enters a value that cannot be converted to an integer).
<TextBox Name="textBox3" Width="50" FontSize="15" Grid.Row="4" Grid.Column="1" Margin="2" Validation.ErrorTemplate="{StaticResource validationTemplate}" Style="{StaticResource textBoxInError}"> <TextBox.Text> <Binding Path="Age3" Source="{StaticResource ods}" UpdateSourceTrigger="PropertyChanged"> <Binding.ValidationRules> <ExceptionValidationRule/> </Binding.ValidationRules> </Binding> </TextBox.Text> </TextBox>
You have the option to provide custom logic to handle those exceptions. The following example shows how to use the UpdateSourceExceptionFilter property to set an UpdateSourceExceptionFilterCallback:
BindingExpression myBindingExpression = textBox3.GetBindingExpression(TextBox.TextProperty);
Binding myBinding = myBindingExpression.ParentBinding;
myBinding.UpdateSourceExceptionFilter = new UpdateSourceExceptionFilterCallback(ReturnExceptionHandler);
myBindingExpression.UpdateSource();
The following is an example implementation of an UpdateSourceExceptionFilterCallback:
object ReturnExceptionHandler(object bindingExpression, Exception exception) { return "This is from the UpdateSourceExceptionFilterCallBack."; }
For the complete sample, see Binding Validation Sample.
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.