[Question] Red border always visible about dotnet

Hello grizoood, thank you for your interest in Windows Community Toolkit!

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[michael-hawker]

Thanks for providing more details @grizoood, didn't see this initially when I responded to your discussion here.

Going to transfer this to the .NET Community Toolkit repo where the MVVM Toolkit lives. FYI @Sergio0694

[Sergio0694]

Hi @grizoood! Would you be able to provide us a minimal repro? That would help us a lot to investigate this. By that I mean the minimum possible amount of code that can reproduce the issue (eg. literally just a single control in XAML with just a line for a binding, and the smallest viewmodel you can get, with like a single property and the minimum amount of validation possible, no comments, no extra code, etc.). Additionally, does the issue only happen with that custom setter you have, or can you also repro with eg. a TextBlock binding its text? Thanks! 🙂

[grizoood]

Sorry for the late reply, I put the issue on hold.

Validation works if I add a null style to hide cell validation:

Validation.ErrorTemplate" Value="{x:Null}"

<DataGridTemplateColumn.CellStyle>
    <Style TargetType="{x:Type DataGridCell}">
        <Style.Resources>
            <Style TargetType="{x:Type ContentPresenter}">
                <Setter Property="Validation.ErrorTemplate" Value="{x:Null}"/>
            </Style>
        </Style.Resources>
    </Style>
</DataGridTemplateColumn.CellStyle>

Before: I have 2 borders (DataGridCell and TextBox)

Après: I have 1 border (TextBox)

<DataGridTemplateColumn Header="Start DataGridTemplateColumn (TextBox)">
    <DataGridTemplateColumn.CellStyle>
        <Style TargetType="{x:Type DataGridCell}">
            <Style.Resources>
                <Style TargetType="{x:Type ContentPresenter}">
                    <Setter Property="Validation.ErrorTemplate" Value="{x:Null}"/>
                </Style>
            </Style.Resources>
        </Style>
    </DataGridTemplateColumn.CellStyle>
    <DataGridTemplateColumn.CellTemplate>
        <DataTemplate>
            <TextBox Text="{Binding Start, UpdateSourceTrigger=PropertyChanged}" Margin="5">
                <TextBox.Style>
                    <Style TargetType="TextBox">
                        <Style.Triggers>
                            <Trigger Property="Validation.HasError" Value="true">
                                <Setter Property="ToolTip" Value="{Binding (Validation.Errors)/ErrorContent, RelativeSource={RelativeSource Self}}"/>
                            </Trigger>
                        </Style.Triggers>
                    </Style>
                </TextBox.Style>
            </TextBox>
        </DataTemplate>
    </DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>

I didn't have the problem with the DataGridTextColumn because I was directly modifying the cell style of the DataGridTextColumn but not for the DataGridTemplateColumn.