CODEWITHSUNDEEP
wpfmvvm
tzerb
tzerb

Reputation: 1433

ListView different controls based on bound value

I have a ListView that displays a link button. I need the link button only to display if the 'FileAddress' string has a value. It should display a simple TextBlock with the Title otherwise.

<GridViewColumn.CellTemplate>
    <DataTemplate>
        <Button Style="{StaticResource LinkButton}" Height="23" Content="{Binding Path=Title}" />
    </DataTemplate>
</GridViewColumn.CellTemplate>

Any ideas would be appreciated.

TIA.

Upvotes: 1

Views: 505

Answers (2)

J. Lennon
J. Lennon

Reputation: 3361

I consider the "gridview" a simple component of wpf .. Where is a bit clumsy to carry out this type of change.

You can make three different approaches:

1) Use GridViewColumn.CellTemplateSelector ( http://www.switchonthecode.com/tutorials/wpf-tutorial-how-to-use-a-datatemplateselector )
Although I do not like = (

2) Create a UserControl that behaves as desired.
It seems appropriate and relatively easy

3) Change the button style through a trigger:

         <Button.Style>
            <Style TargetType="Button">
                <Style.Triggers>
                    <Trigger Property="Content" Value="{x:Null}">
                        <!-- Changes -->
                    </Trigger>
                </Style.Triggers>
            </Style>
        </Button.Style>

or

             <Style TargetType="Button">
                <Setter Property="Template">
                    <Setter.Value>
                        <ControlTemplate TargetType="Button">
                            <Grid>
                                <!-- Template -->
                            </Grid>
                            <ControlTemplate.Triggers>
                                <Trigger Property="Content" Value="{x:Null}">
                                    <!-- Changes -->
                                </Trigger>
                            </ControlTemplate.Triggers>
                        </ControlTemplate>
                    </Setter.Value>
                </Setter>
            </Style>

There are limitations when using the trigger, sometimes you end up having to create a new template for the button, if you know messing with xaml is relatively easy and simple to do.

Sample (I have a button here and I'm changing his image):

 <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type Button}">
                <Grid Width="{TemplateBinding Width}" Height="{TemplateBinding Height}">
                    <Image x:Name="imgBackground" Source="{StaticResource UpArrowImageNormal}" Stretch="None"/>
                </Grid>
                <ControlTemplate.Triggers>
                    <Trigger Property="IsPressed" Value="True">
                        <Setter TargetName="imgBackground"
                                Property="Source" Value="{StaticResource UpArrowImageIsPressed}"/>
                    </Trigger>
                    <Trigger Property="IsEnabled" Value="False">
                        <Setter TargetName="imgBackground" Property="Source" Value="{StaticResource UpArrowImageDisabled}"/>
                    </Trigger>
                </ControlTemplate.Triggers>
            </ControlTemplate>
        </Setter.Value>
    </Setter>

Upvotes: 2

jimmyjambles
jimmyjambles

Reputation: 1670

You could use the following converter

[ValueConversion(typeof(Object), typeof(Visibility))]
public class NullVisibilityConv : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        if (value == null) return Visibility.Collapsed;
        else return Visibility.Visible;
    }

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

}

You can then bind to the control using the following xaml

<GridViewColumn.CellTemplate>
    <DataTemplate>
        <Button Style="{StaticResource LinkButton}" Height="23" Content="{Binding Path=Title}"
                Visibility="{Binding FileAddress, Converter={StaticResource NullToVisConverter}}"/>
    </DataTemplate>
</GridViewColumn.CellTemplate>

You also need to declare the converter as a resource somewhere in your xaml

<converters:NullVisibilityConv x:Key="NullToVisConverter" />

An advantage of this approach is that once you declare the converter in your code you can then re-use it again on other bindings without adding triggers or any other complex code, just use that converter on your visibility binding

Upvotes: 0

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