WPF Button Visibility

I am using MVVM architecture to develop a WPF application...

So far everything has been going fine.

I have run into an issue with binding visibility. I want to minimize writing code in the code behind if i can but if it's REQUIRED then I don't mind doing it.

I have a ViewModel. THis model exposes a boolean and 2 commands. A connect command, a disconnect command, and a DeviceCurrentlyConnected Bool.

Basically I have decided to make 2 buttons but have the button visibility based on the boolean.

So i have had a hard time with this. I tried styles with triggers for a long tim开发者_开发百科e.

<Button Visibility="Hidden" Content="{x:Static UIStrings:ClientStrings.DeviceBar_DisconnectCommandName}" VerticalAlignment="Center" HorizontalAlignment="Center" Height="{Binding ElementName=this.Content, Path=DesiredHeight}" Margin="10" Name="Disconnect" Command="{Binding DisconnectCurrentDeviceCommand}">
    <Button.Style>
        <Style TargetType="Button">
            <Style.Triggers>
                <DataTrigger Binding="{Binding DataCotext.DeviceConnected, RelativeSource={RelativeSource FindAncestor, AncestorType=UserControl}}" Value="True">
                    <Setter Property="Visibility" Value="Visible"/>
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </Button.Style>
</Button>

I can not get styles to work at all.

Basically the functionality that I want is:

DeviceConnected = false: Display a button with content Connect and command bound to the ConnectCommand.

DeviceConnected = true: Display a button with content disconnect and command bound to the DisconnectCommand.

for a button to be displayed and bound to the connect device when no device is currently connect and for a button to be displayed when a device is connected that is bound to the disconnect command and to say the word disconnect.

Write up a bool to visibility converter and then use the converter on your buttons. Five minute recipe for a decent BoolToVisibilityConverter is a good post to read up on creating/using a visibility converter.

What I've done in the past is use a bool to visibility converter and passed in the button's IsEnabled property as the parameter to the converter. Since the button is dis/enabled by the command in the model with the CanExecute method, you can then use the IsEnabled property to set the visibility of the button with the converter.

The reason that your trigger doesn't work is that the style is overridden by the attribute on the button itself.

You can use a converter as Metro Smurf suggests, alternatively you can move the visibility attribute into the style so that the trigger works properly

Just add:

<Style.Setters>
    <Setter Property="Visibility" Value="Hidden" />
</Style.Setters>

To the style and then remove the attribute.