I'm using framework 4.0.
How to display grayed text in editable combobox when it is empty and not focused like in picture
UPDATE:
There is no direct way to implement in WPF except using a TextBlock and ComboBox and laying them over each other.
<Grid HorizontalAlignment="Left" Height="21.545" VerticalAlignment="Top" Width="120.964" Margin="56.958,108.962,0,0">
<ComboBox IsEditable="True" Name="myComboBox" HorizontalAlignment="Left" VerticalAlignment="Top" Width="120">
<!--Items Here-->
</ComboBox>
<TextBlock Text="Please Select" IsHitTestVisible="False" Foreground="Gray" x:Name="textBlock" HorizontalAlignment="Left" TextWrapping="Wrap" Margin="3.993,2.664,0,0">
<TextBlock.Style>
<Style TargetType="TextBlock">
<Style.Setters>
<Setter Property="Visibility" Value="Hidden" />
</Style.Setters>
<Style.Triggers>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding Text, ElementName=myComboBox, Mode=OneWay}" Value=""/>
<Condition Binding="{Binding IsKeyboardFocusWithin, ElementName=myComboBox, Mode=OneWay}" Value="False" />
</MultiDataTrigger.Conditions>
<MultiDataTrigger.Setters>
<Setter Property="Visibility" Value="Visible" />
</MultiDataTrigger.Setters>
</MultiDataTrigger>
</Style.Triggers>
</Style>
</TextBlock.Style>
</TextBlock>
</Grid>
Sorry about this. I misunderstood the question previously. This answer is for UWP.
I think placeholder text is what you are looking for. Check this out ComboBox.PlaceholderText property in MSDN Docs.
Related
I have a TextBlock and I have a MultiDataTrigger defined as, if both properties are false, then I want the TextBlock to move to an other grid column. Problem is the entire style doesn't work at all. It doesn't even set the default Grid.Column to 5. Please help. Making an edit to the post, the first two textblocks are collapsed and shown correctly
<TextBlock
Name="PlateBarcodeTextBlock"
Grid.Column="3"
Text="{Binding Barcode}"
Visibility="{Binding ShowBarCodeForPlate,
Converter={StaticResource boolToVisibility}}" />
<!--Plate Size-->
<TextBlock
Name="PlateSizeTextBlock"
Grid.Column="4"
Style="{StaticResource PlateSizeDisplayStyle}"
Visibility="{Binding ShowSelectedPlateSize,
Converter={StaticResource boolToVisibility}}"/>
<TextBlock
Name="ProtocolNameTextBlock"
Text="{Binding ProtocolName}" >
<TextBlock.Style>
<Style TargetType="{x:Type TextBlock}">
<Setter Property="Grid.Column" Value="5"></Setter>
<Style.Triggers>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding ShowBarCodeForPlate}"
Value="False"/>
<Condition Binding="{Binding ShowSelectedPlateSize}"
Value="False"/>
</MultiDataTrigger.Conditions>
<Setter Property="Grid.Column" Value="3"></Setter>
</MultiDataTrigger>
</Style.Triggers>
</Style>
</TextBlock.Style>
</TextBlock>
On my Grid I Have TextBlock and Button.
If Button is not visible I want my TextBlock.HorizontalAlignment to be set to Center.
If Button is visible I want my TextBlock.HorizontalAlignment to be set to Right. Here is my code:
<TextBlock Grid.Row="0" VerticalAlignment="Center" Name="myTextBlock" Text="{Binding TileTextId}" TextWrapping="Wrap" TextAlignment="Center" >
<TextBlock.Triggers>
<DataTrigger Binding="{Binding ElementName=myButton, Path=IsVisible}" Value="True">
<Setter Property="HorizontalAlignment" Value="Right" />
</DataTrigger>
</TextBlock.Triggers>
</TextBlock>
I get the error:
'HorizontalAlignment' member is not valid because it does not have a qualifying type name.
So I tried to add TextBlock.HorizontalAlignment, like this:
<TextBlock Grid.Row="0" VerticalAlignment="Center" Name="myTextBlock" Text="{Binding TileTextId}" TextWrapping="Wrap" TextAlignment="Center" >
<TextBlock.Triggers>
<DataTrigger Binding="{Binding ElementName=myButton, Path=IsVisible}" Value="True">
<Setter Property="TextBlock.HorizontalAlignment" Value="Right" />
</DataTrigger>
</TextBlock.Triggers>
</TextBlock>
I get the error:
XamlParseException
How should I do that?
Don't try to use TextBlock.Triggers, instead go for a Style with Style.Triggers.
<StackPanel>
<TextBlock Text="TextBlock Content" Margin="5">
<TextBlock.Style>
<Style TargetType="TextBlock">
<Setter Property="HorizontalAlignment" Value="Center"/>
<Style.Triggers>
<DataTrigger Binding="{Binding ElementName=myButton,Path=IsVisible}" Value="True">
<Setter Property="HorizontalAlignment" Value="Right"/>
</DataTrigger>
</Style.Triggers>
</Style>
</TextBlock.Style>
</TextBlock>
<Button x:Name="myButton" Content="Click Me!" Margin="5"/>
</StackPanel>
Take note of the documentation, as it mentions, why style triggers are needed here.
Note that the collection of triggers established on an element only
supports EventTrigger, not property triggers (Trigger). If you require
property triggers, you must place these within a style or template and
then assign that style or template to the element either directly
through the Style property, or indirectly through an implicit style
reference.
Try to do this with Style
<TextBlock Grid.Row="0" VerticalAlignment="Center" Name="myTextBlock" Text="{Binding TileTextId}" TextWrapping="Wrap" TextAlignment="Center" >
<TextBlock.Style>
<Style TargetType="TextBlock">
<Style.Triggers>
<DataTrigger Binding="{Binding ElementName=myButton, Path=IsVisible}" Value="True">
<Setter Property="HorizontalAlignment" Value="Right" />
</DataTrigger>
</Style.Triggers>
</Style>
</TextBlock.Style>
</TextBlock>
i hope you can help me. I got following Code in the Resources:
<UserControl.Resources>
<BitmapImage x:Key="img_src_lock" UriSource="/EEBase;component/Images/Lock_24x32.png" />
<BitmapImage x:Key="img_src_unlock" UriSource="/EEBase;component/Images/Unlock_24x32.png" />
<Style TargetType="{x:Type ToggleButton}">
<Style.Triggers>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource Self}, Path=IsChecked}" Value="True">
<Setter Property="Content">
<Setter.Value>
<Image Source="{StaticResource img_src_lock}" />
</Setter.Value>
</Setter>
</DataTrigger>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource Self}, Path=IsChecked}" Value="False">
<Setter Property="Content">
<Setter.Value>
<Image Source="{StaticResource img_src_unlock}" />
</Setter.Value>
</Setter>
</DataTrigger>
</Style.Triggers>
</Style>
<!-- TypeComboTemplateCollapsed -->
<DataTemplate x:Key="TypeComboTemplateCollapsed">
<TextBlock
Text="{Binding Path=Text, Mode=OneWay}"
VerticalAlignment="Center"
HorizontalAlignment="Left"
Margin="5,0,0,5"
/>
</DataTemplate>
<!-- TypeComboTemplateExpanded -->
<DataTemplate x:Key="TypeComboTemplateExpanded">
<TextBlock
Text="{Binding Path=Text, Mode=OneWay}"
VerticalAlignment="Center"
Margin="5,0,0,5"
/>
</DataTemplate>
<!-- EditCircleTemplate -->
<DataTemplate x:Key="EditCircleTemplate">
<!-- some content here, no ToggleButton -->
</DataTemplate>
<!-- EditRectangleTemplate -->
<DataTemplate x:Key="EditRectangleTemplate">
<!-- some other content here, including the ToggleButtons -->
<ToggleButton
IsChecked="{Binding Path=BaseLocked, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}"
Margin="5"
/>
<ToggleButton
IsChecked="{Binding Path=HeightLocked, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}"
Margin="5"
/>
</DataTemplate>
</UserControl.Resources>
To me that looks all correct.
Now, the problem is:
When i do the following, an exceptions occurs:
Specified element is already the logical child of another element. Disconnect it first.
1. load the control, selected type is CIRC
2. change the dropdown to select RECT (template triggers and togglebuttons are shown correctly)
3. change the dropdown back to CIRC
--> now the Exception occurs.
4. if i ignore the exception, the template "EditCircleTemplate" does not get loaded, and the normal ToString of the model object gets displayed.
Additional info:
originally there are 4 different types in the WPF, two of them with ToggleButtons (that's why i use templates). I cut them out, they dont differ really. But what i found out using all 4 templates is that the error does not occur when switching to a new Template, but when unloading a template with the toggle buttons. Which is kinda strange.
Also if i remove the DataTriggers for the ToggleButtons everything works like a charm.
The Exception comes from the XAML-Interpreter, so the Stacktrace is not useful at all.
Can anyone give me a hint what i am doing wrong?
Edit:
oops, i guess i forgot the content code:
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="160"/>
<ColumnDefinition />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition />
</Grid.RowDefinitions>
<ComboBox
Margin="5"
Grid.Row="0"
Grid.Column="0"
ItemsSource="{Binding Path=PossibleTypes, Mode=OneTime}"
SelectedItem="{Binding Path=SelectedType, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}">
<ComboBox.ItemTemplate>
<DataTemplate>
<StackPanel>
<ContentControl x:Name="content" Content="{Binding}" ContentTemplate="{StaticResource TypeComboTemplateExpanded}"/>
</StackPanel>
<DataTemplate.Triggers>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=ComboBoxItem}}" Value="{x:Null}">
<Setter TargetName="content" Property="ContentTemplate" Value="{StaticResource TypeComboTemplateCollapsed}"/>
</DataTrigger>
</DataTemplate.Triggers>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
<ContentControl
Grid.Column="0"
Grid.Row="1"
Grid.ColumnSpan="2"
Content="{Binding Mode=OneWay}">
<ContentControl.ContentTemplate>
<DataTemplate >
<ContentControl
Name="inputContent"
Content="{Binding Mode=OneWay}"
ContentTemplate="{x:Null}"
/>
<DataTemplate.Triggers>
<DataTrigger
Binding="{Binding Path=SelectedType.Type, Mode=OneWay}"
Value="CIRC">
<Setter
TargetName="inputContent"
Property="ContentTemplate"
Value="{StaticResource EditCircleTemplate}"
/>
</DataTrigger>
<DataTrigger
Binding="{Binding Path=SelectedType.Type, Mode=OneWay}"
Value="RECT">
<Setter
TargetName="inputContent"
Property="ContentTemplate"
Value="{StaticResource EditRectangleTemplate}"/>
</DataTrigger>
</DataTemplate.Triggers>
</DataTemplate>
</ContentControl.ContentTemplate>
</ContentControl>
</Grid>
Edit2/Solution:
I just found a workaround - it just does not satisfy me:
Instead of putting the style in the UserControl.Resources, which for me would be the more clean and intuitive solution, i have to set the style with the triggers on each ToggleButton separately.
So removing the and adding following code to each ToggleButton did the trick:
<ToggleButton.Style>
<Style TargetType="{x:Type ToggleButton}">
<Style.Triggers>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource Self}, Path=IsChecked}" Value="True" >
<Setter Property="Content">
<Setter.Value>
<Image Source="{StaticResource img_src_lock}" />
</Setter.Value>
</Setter>
</DataTrigger>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource Self}, Path=IsChecked}" Value="False">
<Setter Property="Content">
<Setter.Value>
<Image Source="{StaticResource img_src_unlock}" />
</Setter.Value>
</Setter>
</DataTrigger>
</Style.Triggers>
</Style>
</ToggleButton.Style>
The big question still persists: WHY?
The problem is that if you create an Image in a style there is only one instance, so as soon as multiple controls use the style there is going to be a fight over this one instance which can only be owned by one control.
The easiest solution to this is placing the Style in a resource and setting x:Shared to false, that way a copy of the style is used whereever referenced.
Why do you need to create BitmapImages and set them as Source to your Content Images in Triggers? Why arent you using the URI source to Images directly?
<Style TargetType="{x:Type ToggleButton}">
<Style.Triggers>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource Self}, Path=IsChecked}" Value="True">
<Setter Property="Content">
<Setter.Value>
<Image Source="/EEBase;component/Images/Lock_24x32.png" />
</Setter.Value>
</Setter>
</DataTrigger>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource Self}, Path=IsChecked}" Value="False">
<Setter Property="Content">
<Setter.Value>
<Image Source="/EEBase;component/Images/Unlock_24x32.png" />
</Setter.Value>
</Setter>
</DataTrigger>
</Style.Triggers>
</Style>
Let me know if this helps.
I seem to be having a hard time today. All I want to do is make a TextBox hidden of visible based on a bool value databound to the Window its hosted in.
What I have just won't compile and I don't understand why. Please help.
<TextBlock Grid.Column="2" Text="This order will be sent to accounting for approval"
Foreground="Red" VerticalAlignment="Center" FontWeight="Bold" Padding="5">
<TextBlock.Style>
<Style>
<Style.Triggers>
<DataTrigger Binding="{Binding Path=AllowedToSubmit}" Value="True">
<Setter Property="Visibility" Value="Hidden" />
</DataTrigger>
</Style.Triggers>
</Style>
</TextBlock.Style>
</TextBlock>
You need to set the Style.TargetType in order for it to recognize the Visibility property:
<TextBlock Grid.Column="2" VerticalAlignment="Center" FontWeight="Bold" Foreground="Red" Padding="5" Text="This order will be sent to accounting for approval">
<TextBlock.Style>
<Style TargetType="{x:Type TextBlock}">
<Style.Triggers>
<DataTrigger Binding="{Binding Path=AllowedToSubmit}" Value="True">
<Setter Property="Visibility" Value="Hidden"/>
</DataTrigger>
</Style.Triggers>
</Style>
</TextBlock.Style>
</TextBlock>
Your binding path to AllowedToSubmit probably needs to have ElementName set to the Window's name, as well.
Another option is to bind TextBlock.Visibility directly to the property:
<Window>
<Window.Resources>
<BooleanToVisibilityConverter x:Key="BoolToVisibility" />
</Window.Resources>
<TextBlock Visibility="{Binding Path=AllowedToSubmit, Converter={StaticResource BoolToVisibility}}" />
</Window>
If you want it to work like in your sample, where true hides the TextBlock, then you can write your own converter to convert opposite of the built-in BooleanToVisibilityConverter.
I have a listbox, and I have the following ItemTemplate for it:
<DataTemplate x:Key="ScenarioItemTemplate">
<Border Margin="5,0,5,0"
Background="#FF3C3B3B"
BorderBrush="#FF797878"
BorderThickness="2"
CornerRadius="5">
<DockPanel>
<DockPanel DockPanel.Dock="Top"
Margin="0,2,0,0">
<Button HorizontalAlignment="Left"
DockPanel.Dock="Left"
FontWeight="Heavy"
Foreground="White" />
<Label Content="{Binding Path=Name}"
DockPanel.Dock="Left"
FontWeight="Heavy"
Foreground="white" />
<Label HorizontalAlignment="Right"
Background="#FF3C3B3B"
Content="X"
DockPanel.Dock="Left"
FontWeight="Heavy"
Foreground="White" />
</DockPanel>
<ContentControl Name="designerContent"
Visibility="Collapsed"
MinHeight="100"
Margin="2,0,2,2"
Content="{Binding Path=DesignerInstance}"
Background="#FF999898">
</ContentControl>
</DockPanel>
</Border>
</DataTemplate>
As you can see the ContentControl has Visibility set to collapsed.
I need to define a trigger that causes the Visibility to be set to "Visible"
when the ListItem is selected, but I can't figure it out.
Any ideas?
UPDATE: Of course I could simply duplicate the DataTemplate and add triggers
to the ListBox in question to use either one or the other, but I want to prevent duplicating this code.
You can style your ContentControl such that a trigger fires when its container (the ListBoxItem) becomes selected:
<ContentControl
x:Name="designerContent"
MinHeight="100"
Margin="2,0,2,2"
Content="{Binding Path=DesignerInstance}"
Background="#FF999898">
<ContentControl.Style>
<Style TargetType="{x:Type ContentControl}">
<Setter Property="Visibility" Value="Collapsed"/>
<Style.Triggers>
<DataTrigger
Binding="{Binding
RelativeSource={RelativeSource
Mode=FindAncestor,
AncestorType={x:Type ListBoxItem}},
Path=IsSelected}"
Value="True">
<Setter Property="Visibility" Value="Visible"/>
</DataTrigger>
</Style.Triggers>
</Style>
</ContentControl.Style>
</ContentControl>
Alternatively, I think you can add the trigger to the template itself and reference the control by name. I don't know this technique well enough to type it from memory and assume it'll work, but it's something like this:
<DataTemplate x:Key="ScenarioItemTemplate">
<DataTemplate.Triggers>
<DataTrigger
Binding="{Binding
RelativeSource={RelativeSource
Mode=FindAncestor,
AncestorType={x:Type ListBoxItem}},
Path=IsSelected}"
Value="True">
<Setter
TargetName="designerContent"
Property="Visibility"
Value="Visible"/>
</DataTrigger>
</DataTemplate.Triggers>
...
</DataTemplate>
#Matt, Thank you!!!
Just had to add a trigger for IsSelected == false as well,
and now it works like a charm!
<ContentControl.Style>
<Style TargetType="{x:Type ContentControl}">
<Setter Property="Visibility" Value="Collapsed"/>
<Style.Triggers>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource Mode=FindAncestor,AncestorType={x:Type ListBoxItem}},Path=IsSelected}" Value="True">
<Setter Property="Visibility" Value="Visible"/>
</DataTrigger>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource Mode=FindAncestor,AncestorType={x:Type ListBoxItem}},Path=IsSelected}" Value="False">
<Setter Property="Visibility" Value="Collapsed"/>
</DataTrigger>
</Style.Triggers>
</Style>