Question

I’m using .NET 3.5

I have a DataGridTextColumn that I want to turn the background color red when the value of that column is false. I have seen this done in XMAL but cannot figure out how to do it in code behind

DataGridTextColumn column = new DataGridTextColumn() { Header = "Can Connect", Binding = new Binding("CanConnect") };
//How to add the converter here so that the background of the cell turns red when CanConnect = false?

    public class IsConnectedConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            bool input = (bool)value;
            switch (input)
            {
                case true:
                    return DependencyProperty.UnsetValue;
                default:
                    return Brushes.Red;
            }
        }
    }

Answer 1

Use the Converter property of the Binding class:

new Binding("CanConnect") {
    Converter = new IsConnectedConverter()
}

In your code, you are assigning your binding to the Binding property of the DataGridTextColumn, but that property only controls the contents of the cell. For the visual appearance of the cell, you will need a style, which can also be set in code-behind:

Style st = new Style(typeof(DataGridCell));
st.Setters.Add(new Setter(Control.BackgroundProperty, binding));
column.CellStyle = st;

In that code, binding would be a variable with your new Binding object (or the above constructor and initialization call right away). As described by the docs on DataGridTextColumn.CellStyle, the target type of the style must be DataGridCell, and as that class inherits from Control, we can add setters for dependency properties of Control, such as Background.

I’m afraid I can’t test this code right now; I hope it gives you an idea on how to proceed.