CODEWITHSUNDEEP
c#.netwpfxamlcommand
Tomasz Grobelny
Tomasz Grobelny

Reputation: 2746

wpf command control visibility

I have a custom command:

public static class CommandLibrary
{
    private static RoutedUICommand cmdMyCommand = new RoutedUICommand("My command", "MyCommand", typeof(CommandLibrary));
    public static RoutedUICommand MyCommand{ get { return cmdMyCommand ; } }
}

and I register a binding like this

CommandManager.RegisterClassCommandBinding(typeof(SomeClass), new CommandBinding(CommandLibrary.MyCommand, new ExecutedRoutedEventHandler(myCommandExecuteHandler), new CanExecuteRoutedEventHandler(myCommandCanExecuteHandler)));

And in generic.xaml I have a Buton with Command property set. The button is being properly enabled/disabled based on logic in myCommandCanExecuteHandler.

But now I would like to also control this button's visibility (independent of CanExecute which is mapped to IsEnabled). How do I approach that problem?

A discussion about the same problem is available here: http://social.msdn.microsoft.com/forums/en-US/wpf/thread/c20782f8-2d04-49d3-b822-f77b4b87c27a/, but somehow the idea that CanBeSeen is a property of RoutedUICommand derived class does not appeal to me.

Upvotes: 2

Views: 3584

Answers (3)

Sam Vemagiri
Sam Vemagiri

Reputation: 119

I ran into a very similar problem today.

"Sometimes" the CanExecute binding is being ignored when the visibility of the button is set collapsed state by the visibility converter. I said "sometimes" because, if I put a breakpoint in the visibility converter, it alters the behaviour.

When the visibility is changed to Visible - the CanExecute is not being called again. A mouse click anywhere on the UI refreshes the CanExecute binding, which makes it work as expected.

I worked around this issue by binding to the Button IsEnabled property directly to a property on my viewmodel, which reflects what my CanExecute does.

Upvotes: 0

uowzd01
uowzd01

Reputation: 1000

you can bind the the visibility attribute in xaml to the value which decides button's visibility

<Button Content="Button" Height="23" Visibility="{Binding someclass, Converter={Binding VisibitlityConverter}}"/>

and use a converter to convert bool value to callpsed or visible

class visibilityConverter : IValueConverter
{
    #region IValueConverter Members

    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        return (bool)value == true? Visibility.Visible : Visibility.Collapsed;
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }

    #endregion
}

Upvotes: 1

David Bekham
David Bekham

Reputation: 2175

Do you want to make the button to be visible when the button is enabled/disabled... If then you have to bind the IsEnabled property to Visibility property using the Boolean to Visibility converter...

Upvotes: 0

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