UpdateSourceTrigger=Explicit

Question

I'm creating a WPF window with multiple textboxes, when the user presses the OK button I want all the text boxes to be evaluated for being non-blank. I understand that I have to use TextBoxes with 'UpdateSourceTrigger of 'Explicit', but do I need to call 'UpdateSource()' for each of them ? e.g.

<TextBox Height="23" 
     HorizontalAlignment="Left" 
     Margin="206,108,0,0" 
     Text="{Binding Path=Definition, UpdateSourceTrigger=Explicit}"
     Name="tbDefinitionFolder" 
     VerticalAlignment="Top" 
     Width="120" />

<TextBox Height="23" 
     HorizontalAlignment="Left" 
     Margin="206,108,0,0" 
     Text="{Binding Path=Release, UpdateSourceTrigger=Explicit}"
     Name="tbReleaseFolder" 
     VerticalAlignment="Top" 
     Width="120" />

...

BindingExpression be = tbDefinitionFolder.GetBindingExpression(TextBox.TextProperty);
be.UpdateSource();
BindingExpression be2 = tbReleaseFolder.GetBindingExpression(TextBox.TextProperty);
be2.UpdateSource();

Answer 1

If you use Explicit you need to call UpdateSource.

I am not sure if this is the best approach to what you try to do though, i for one virtually never use Explicit, i rather bind to a copy of an object if i do not want changes to apply right away, or i store a copy and revert everything back if edits are to be cancelled.