CODEWITHSUNDEEP
c#wpftextblock
BrianKE
BrianKE

Reputation: 4185

WPF Add text to TextBlock based on property

I have a ListView with a column that shows the state two letter appreviation. Based on the value of a Boolean property (HasWorkState) I would like to add parenthesis around the state abbreviation when HasWorkState = false.

For instance:

The state abbreviation is displayed in a GridViewColumn:

<!-- Work State -->
<GridViewColumn Width="{Binding ActualWidth, 
                          RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Grid}}, 
                          Converter={StaticResource MathConverter}, ConverterParameter=(x/10)*0.5}">
    <GridViewColumn.Header>
        <GridViewColumnHeader Content=" State"
                              HorizontalContentAlignment="Left" />
    </GridViewColumn.Header>
    <GridViewColumn.CellTemplate>
        <DataTemplate>
            <TextBlock Text="{Binding WorkState}"
                       Style="{StaticResource StateStyle}" />
        </DataTemplate>
    </GridViewColumn.CellTemplate>
</GridViewColumn>

To this GridViewColumn I have applied this style:

<!-- Highlight missing work states -->
<Style x:Key="StateStyle" TargetType="TextBlock">
    <Style.Triggers>
        <DataTrigger Binding="{Binding HasWorkState}" Value="False">
            <Setter Property="Text" Value="{Binding StringFormat=({0})}" />
            <Setter Property="ToolTip" Value="Work location unspecified. Using residence state." />
        </DataTrigger>
    </Style.Triggers>
</Style>

I know this style is being applied correctly as the ToolTip is being displayed when HasWorkState = false. I just need to know how to add the parenthesis. What I currently have for the Text value setter is not working.

Upvotes: 0

Views: 1533

Answers (2)

15ee8f99-57ff-4f92-890c-b56153
15ee8f99-57ff-4f92-890c-b56153

Reputation: 37059

You've got a solution, but it's worth knowing why you had the problem: Because you're setting Text with an attribute on the TextBlock element, the style can't override that. If you used a style setter to apply the default {Binding WorkState}, the style would be able to override it.

I prefer to keep things like this in the view, so my approach would be this:

<ContentControl Content="{Binding WorkState}" Style="{StaticResource StateStyle}" />

State style:

<Style x:Key="StateStyle" TargetType="ContentControl">
    <Style.Triggers>
        <DataTrigger Binding="{Binding HasWorkState}" Value="False">
            <!-- Leave the content alone and just change the format string -->
            <Setter Property="ContentStringFormat" Value="({0})" />

            <Setter 
                Property="ToolTip" 
                Value="Work location unspecified. Using residence state." 
                />
        </DataTrigger>
    </Style.Triggers>
</Style>

Upvotes: 2

Adam Brown
Adam Brown

Reputation: 1729

The best way is to add that property to your view model. Something like this in your view model:

internal class StateStyleViewModel : INotifyPropertyChanged
{
    private bool hasWorkState;
    private string workState;
    public event PropertyChangedEventHandler PropertyChanged;

    private string WorkState
    {
        get { return workState; }
        set
        {
            if (value == workState) return;
            workState = value;
            OnPropertyChanged();
            //Notify that the value of the dependent property has changed.
            OnPropertyChanged(nameof(DisplayWorkState));
        }
    }

    public bool HasWorkState
    {
        get { return hasWorkState; }
        set
        {
            if (value == hasWorkState) return;
            hasWorkState = value;
            OnPropertyChanged();
            //Notify that the value of the dependent property has changed.
            OnPropertyChanged(nameof(DisplayWorkState));
        }
    }

    /// <summary>
    /// Property for binding
    /// </summary>
    public string DisplayWorkState => HasWorkState ? WorkState : $"({WorkState})";

    [NotifyPropertyChangedInvocator]
    protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

Then you just bind to DisplayWorkState instead of WorkState

Upvotes: 1

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