WPF xaml: How to validate Cells in DataGrid with automatically generated Columns-CodePudding

How can I add cell validation in an automatically generated DataGrid (from DataTable) and style the cell red if the value is not valid?

This is my DataGrid:

    <DataGrid Grid.Row="2"
              Margin="5"
              Background="Transparent"
              MaxHeight="300"
              MaxWidth="500"
              ScrollViewer.CanContentScroll="True"
              HorizontalAlignment="Center"
              VerticalAlignment="Center"
              ItemsSource="{Binding DataTable}"
              HeadersVisibility="None"
              CellStyle="{StaticResource tableCellTheme}"
              CanUserAddRows="False">

I also added

        <DataGrid.RowValidationRules>
            <validation:DataGridValidation ValidationStep="UpdatedValue" />
        </DataGrid.RowValidationRules>

But I do not want to evaluate the whole row and more importantly, I don't know how to style the offending cell red if this returns false... Thanks for your help!

CodePudding user response：

You must handle the DataGrid.AutoGeneratingColumn event, obtain the reference to the column's binding and then enable binding validation and attach the ValidationRule to it:

MainWindow.xaml

<DataGrid AutoGeneratingColumn="EnableCellValidation_OnAutoGeneratingColumn" />

MainWindow.xaml.cs

private void EnableCellValidation_OnAutoGeneratingColumn(object sender, DataGridAutoGeneratingColumnEventArgs e)
{
  if (e.Column is DataGridBoundColumn column)
  {
    var columnBinding = column.Binding as Binding;
    columnBinding.ValidatesOnDataErrors = true;
    columnBinding.ValidationRules.Add(new DataGridValidation());
  }
}