How can I toggle a TextBlock's visibility in a DataTrigger?
-
07-07-2019 - |
Question
This code works (when ControlType="dropDown" then the background yellow):
<Window x:Class="TestCollapsed.Views.MainView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:c="clr-namespace:TestCollapsed.Commands"
Title="Main Window" Height="400" Width="800">
<Window.Resources>
<Style x:Key="DropDownStyle" TargetType="TextBlock">
<Style.Triggers>
<DataTrigger Binding="{Binding ControlType}" Value="dropDown">
<Setter Property="Background" Value="Yellow"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Window.Resources>
<StackPanel>
<TextBlock Visibility="Visible"
Text="This is going to be the dropdown control."
Style="{StaticResource DropDownStyle}"/>
</StackPanel>
</Window>
But this code does not work (when ControlType="dropDown" then the TextBlock is still invisible):
<Window x:Class="TestCollapsed.Views.MainView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:c="clr-namespace:TestCollapsed.Commands"
Title="Main Window" Height="400" Width="800">
<Window.Resources>
<Style x:Key="DropDownStyle" TargetType="TextBlock">
<Style.Triggers>
<DataTrigger Binding="{Binding ControlType}" Value="dropDown">
<Setter Property="Visibility" Value="Visible"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Window.Resources>
<StackPanel>
<TextBlock Visibility="Collapsed"
Text="This is going to be the dropdown control."
Style="{StaticResource DropDownStyle}"/>
</StackPanel>
</Window>
Why can't I set visibility in a style as I can background?
Solution
You're setting the Visibility on the TextBlock and then trying to override it with a style. That won't work. Try this:
<Window x:Class="TestCollapsed.Views.MainView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:c="clr-namespace:TestCollapsed.Commands"
Title="Main Window" Height="400" Width="800">
<Window.Resources>
<Style x:Key="DropDownStyle" TargetType="TextBlock">
<Setter Property="Visibility" Value="Collapsed"/>
<Style.Triggers>
<DataTrigger Binding="{Binding ControlType}" Value="dropDown">
<Setter Property="Visibility" Value="Visible"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Window.Resources>
<StackPanel>
<TextBlock Text="This is going to be the dropdown control."
Style="{StaticResource DropDownStyle}"/>
</StackPanel>
</Window>
OTHER TIPS
I have the same problem. @Bryan's answer is perfect! There are the wrong and right versions. The wrong version:
<TextBlock Text="1999-09-09 16:08" VerticalAlignment="Top" Visibility="Collapsed">
<TextBlock.Style>
<Style BasedOn="{StaticResource TipTextYellow}" TargetType="TextBlock">
<Style.Triggers>
<DataTrigger Binding="{Binding ElementName=Alcohol,Path=IsFocused}" Value="True">
<Setter Property="Visibility" Value="Visible"/>
</DataTrigger>
</Style.Triggers>
</Style>
</TextBlock.Style>
</TextBlock>
The right version:
<TextBlock Text="1999-09-09 16:08" VerticalAlignment="Top">
<TextBlock.Style>
<Style BasedOn="{StaticResource TipTextYellow}" TargetType="TextBlock">
<Setter Property="Visibility" Value="Collapsed"/>
<Style.Triggers>
<DataTrigger Binding="{Binding ElementName=Alcohol,Path=IsFocused}" Value="True">
<Setter Property="Visibility" Value="Visible"/>
</DataTrigger>
</Style.Triggers>
</Style>
</TextBlock.Style>
</TextBlock>
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