Develop Reference

How can I determine where the issue with my MultiDataTrigger is coming from?

I currently have a DataGrid being styled by DataTriggers. I've run into the issue that a MultiDataTrigger will not style the row when one condition is present - a condition that works fine in a DataTrigger.
This Works:
<DataTrigger Binding="{Binding Type}" Value="Error">
<Setter Property="Background" Value="#FFFF88FF"/>
</DataTrigger>
This Works:
<DataTrigger Binding="{Binding BgColor}" Value="{x:Null}">
<Setter Property="Background" Value="#FFFF88FF"/>
</DataTrigger>
This does not work:
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding Type}" Value="Error"/>
<Condition Binding="{Binding BgColor}" Value="{x:Null}"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" Value="#FFFF88FF"/>
</MultiDataTrigger>
What would influence the MultiDataTrigger to not work?
There are multiple instances where both conditions should be met.

Technically it should work ,you can cross verify by adding dummy converter to your XAML and bind the "Type" and "BgColor" to it then you can check exact value

Change background for specific rows in datagrid wpf

I have a datagrid "Funds" bind to a listcollectionview.
I want to highlight specific rows in datagrid based on few rules. The fundGroupsList is the list of group names. The rule1 is to find the misalignment within members of a group.

One of the ways to do that is to create a boolean property (ex. IsRule1Failed) in Entries and save the fail result foreach row.
Then, in XAML use DataTriggers to change the background color.
<DataGrid.Resources>
<Style TargetType="DataGridCell">
<Style.Triggers>
<Trigger Property="IsSelected" Value="True">
<Setter Property="Background" Value="BurlyWood" />
</Trigger>
<DataTrigger Binding="{Binding DataContext.IsRule1Failed}" Value="True">
<Setter Property="Background" Value="Red"></Setter>
</DataTrigger>
</Style.Triggers>
</Style>
</DataGrid.Resources>

You can also simply change the CSS Class of the row.
GridView.SelectedRowStyle.CssClass = "selectedrow";

Better Binding for DataTrigger

I have a TextBlock and I want to set the property Visibility to Collapsed when the TextBlock has no text. I wonder me, for sure there should be a better way to check if the Lenght of the property Text is equal than 0.
<TextBlock Name="TextBlockHeader" Foreground="White" FontSize="18" FontWeight="Bold" Text="{Binding Header}" Margin="0,0,0,25">
<TextBlock.Style>
<Style TargetType="TextBlock">
<Style.Triggers>
<DataTrigger Binding="{Binding ElementName=TextBlockHeader, Path=Text.Length}" Value="0">
<Setter Property="Visibility" Value="Collapsed"></Setter>
</DataTrigger>
</Style.Triggers>
</Style>
</TextBlock.Style>
</TextBlock>
Here I have to define a name for the TextBlock and I can reference it in the Datatrigger Binding="{Binding ElementName=TextBlockHeader, Path=Text.Length}"
But how can I achieve the same without having to define a name for the TextBlock?

You would usually use Triggers instead of DataTriggers, and compare the Text property to either null or an empty string.
<Style TargetType="TextBlock">
<Style.Triggers>
<Trigger Property="Text" Value="{x:Null}">
<Setter Property="Visibility" Value="Collapsed"/>
</Trigger>
<Trigger Property="Text" Value="">
<Setter Property="Visibility" Value="Collapsed"/>
</Trigger>
</Style.Triggers>
</Style>
As the TextBlock class seems to coerce the Text property value to be non-null, it may be sufficient to have only the second Trigger for an empty string.

Dynamically changing content of ContentControl via trigger

I need to flip between two views dynamically based on a boolean flag in my ViewModel.
I thought it would be as simple as:
<ContentControl>
<ContentControl.Style>
<Style TargetType="ContentControl">
<Setter Property="Content" Value="{StaticResource View1}" />
<Style.Triggers>
<DataTrigger Binding="{Binding IsShowingView2}">
<Setter Property="Content" Value="{StaticResource View2}" />
</DataTrigger>
</Style.Triggers>
</Style>
</ContentControl.Style>
</ContentControl>
However, View2 never gets displayed, even if IsShowingView2 is always true.
Any ideas anyone? All the examples I can find seem to be altering the ContentTemplate instead, but I have no need to do that. I just want different content.

You're not actually setting a value for the DataTrigger
<DataTrigger Binding="{Binding IsShowingView2}" Value="True">
<Setter Property="Content" Value="{StaticResource View2}" />
</DataTrigger>
Also check for binding errors in the output window.

Disabling style triggers created in xaml programmatically

I am working on a c# WPF project which I am using a style trigger to style the background colour of the each row based on one of the cell values.
Below is my style trigger.
<Window.Resources>
<Style TargetType="DataGridRow">
<Style.Triggers>
<DataTrigger Binding="{Binding Highest Alarm Level}" Value="Critical">
<Setter Property="Background" Value="Red" />
</DataTrigger>
<DataTrigger Binding="{Binding Highest Alarm Level}" Value="Medium">
<Setter Property="Background" Value="Orange" />
</DataTrigger>
<DataTrigger Binding="{Binding Highest Alarm Level}" Value="Warning">
<Setter Property="Background" Value="Yellow" />
</DataTrigger>
<DataTrigger Binding="{Binding Highest Alarm Level}" Value="Info">
<Setter Property="Background" Value="White" />
</DataTrigger>
</Style.Triggers>
</Style>
</Window.Resources>
What I need to be able to do, is under certain circumstances I don't want this style to be used, so what I am after, is if in the C# code a certain condition becomes to true, I want to disable all of the styling done above to not be used, i.e. all of the styling is turned off so the background colour of the rows are not set.

Add a Key to your custom DataGridRow Style
<Style TargetType="DataGridRow" x:Key="MyRowStyle">
<!-- Define Triggers -->
</Style>
Then you just need to switch between default and custom styles.
If you set Style with null, that means the default Style will be applied
dataGrid.RowStyle = _boolCondition ? this.FindResource("MyRowStyle") as Style : null;