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c#wpfdatagriddatatrigger

Changing background colour of cells if value is greater than or equal to

I have this DataGrid and I have been playing with setting the background colour of selected cells:

<DataGridTextColumn Header="Next Study" Binding="{Binding NextStudy}">
    <DataGridTextColumn.ElementStyle>
        <Style TargetType="{x:Type TextBlock}">
            <Style.Triggers>
                <Trigger Property="Text" Value="25">
                    <Setter Property="Background" Value="Red"/>
                </Trigger>
            </Style.Triggers>
        </Style>
    </DataGridTextColumn.ElementStyle>
    <DataGridTextColumn.CellStyle>
        <Style TargetType="{x:Type DataGridCell}">
            <Setter Property="ToolTip" Value="{Binding NextStudyDescription}" />
        </Style>
    </DataGridTextColumn.CellStyle>
</DataGridTextColumn>

It works as you can see:

Highlighted cells

But that is not really what I want. Instead I would like to highlight all cells where the value is greater than or equal to 18. So I tried:

<DataGridTextColumn Header="Next Study" Binding="{Binding NextStudy}">
    <DataGridTextColumn.ElementStyle>
        <Style TargetType="{x:Type TextBlock}">
            <Style.Triggers>
                <DataTrigger Binding="{NextStudy Converter={StaticResource IsEqualOrGreaterThanConverter}, ConverterParameter=18}" Value="True">
                    <Setter Property="Background" Value="Red"/>
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </DataGridTextColumn.ElementStyle>
    <DataGridTextColumn.CellStyle>
        <Style TargetType="{x:Type DataGridCell}">
            <Setter Property="ToolTip" Value="{Binding NextStudyDescription}" />
        </Style>
    </DataGridTextColumn.CellStyle>
</DataGridTextColumn>

It doesn't like: <DataTrigger Binding="{NextStudy

In addition, I would like to do this background test if the element comboActiveStudentAssignmentType selected index is 0, 1 or 2. Otherwise it does not need to do this highlighting.

Thanks.

Solution

  • You have a syntax error: Binding is the property name, you still have to declare it as a Binding

    <DataTrigger Binding="{Binding NextStudy, Converter={StaticResource IsEqualOrGreaterThanConverter}, ConverterParameter=18}" Value="True">

    As for the second part of the question, you can use a MultiDataTrigger. The conditions in the MultiDataTrigger have to ALL be true for the trigger to execute the setters. You will probably need to write another converter to transform your AssignmentType to True/False and you should be set. Here's a quick example:

    <MultiDataTrigger>
    <MultiDataTrigger.Conditions>
        <Condition Binding="{Binding NextStudy, Converter={StaticResource IsEqualOrGreaterThanConverter}, ConverterParameter=18}" Value="True"/>
        <Condition Binding="{Binding comboActiveStudentAssignmentType, Converter={StaticResource YourOtherConverter}" Value="True"/>
    </MultiDataTrigger.Conditions>
    <MultiDataTrigger.Setters>
        <Setter Property="Background" Value="Red"/>
    </MultiDataTrigger.Setters>
</MultiDataTrigger>