I use the solution presented here to turn binding errors into native Exceptions: http://www.jasonbock.net/jb/Default.aspx?blog=entry.0f221e047de740ee90722b248933a28d
However, a normal scenario in WPF bindings is to throw exceptions in case the user input cannot be converted to the target type (for instance, a TextBox bound to a integer field; the input of a non-numeric string results in a FormatException, the input of number that is too large results in an OverflowException). A similar case is when the Setter of the source property throws an exception.
The WPF way of handling this is via ValidatesOnExceptions=true and ValidationExceptionRule to signal the user the supplied input is not correct (using the exception message).
However, these exception are also send to the output window and thus 'caught' by the BindingListener, resulting in an error...clearly not the behaviour you'd want.
Therefore, I expanded the BindingListener class to NOT throw an Exception in these cases:
private static readonly IList<string> m_MessagesToIgnore =
new List<String>()
{
"ConvertBack cannot convert value",
"Cannot save value from target back to source"
};
Modified lines in public override void WriteLine(string message):
....
if (this.InformationPropertyCount == 0)
{
if (!m_MessagesToIgnore.Any(
x => this.Message.StartsWith(x, StringComparison.InvariantCultureIgnoreCase)))
{
PresentationTraceSources.DataBindingSource.Listeners.Remove(this);
throw new BindingException(this.Message,
new BindingExceptionInformation(this.Callstack,
System.DateTime.Parse(this.DateTime),
this.LogicalOperationStack, int.Parse(this.ProcessId),
int.Parse(this.ThreadId), long.Parse(this.Timestamp)));
}
else
{
this.IsFirstWrite = true;
this.DetermineInformationPropertyCount();
}
}
}
