Binding IsReadOnly using IValueConverter

Question

Maybe I'm misunderstanding how to use an IValueConverter or data binding (which is likely), but I am currently trying to set the IsReadOnly property of a DataGridTextColumn depending on the value of a string. Here is the XAML:

<DataGridTextColumn Binding="{Binding Path=GroupDescription}" Header="Name"
                    IsReadOnly="{Binding Current,
                                 Converter={StaticResource currentConverter}}"/>

And here is my converter:

public class CurrentConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        string s = value as string;
        if (s == "Current")
        {
            return false;
        }
        else
        {
            return true;
        }
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotSupportedException();
    }
}

Currently, the column is always editable, the converter seems to do nothing. Does anyone have some thoughts as to why this is happening?

Updated the end of the question, hopefully it isn't too vague... — mastur cheef, Nov 04 '13 at 21:17
IsReadOnly isn't bindable. See my answer on http://stackoverflow.com/questions/18443063/bind-datagrid-textbox-enable-based-on-checkbox-property/18444724#18444724 — jamesSampica, Nov 04 '13 at 21:24
@mastur - Where property `Current` lies? In your ViewModel class or underlying ItemsSource object? — Rohit Vats, Nov 04 '13 at 21:29
@Rohit It is a DP but it is not a part of the visual tree, thus it does not receive notifications from source changes. [See this for more info](http://connect.microsoft.com/VisualStudio/feedback/details/530280/wpf-4-vs2010-datagrid-isreadonly-does-not-work-with-binding-to-boolean-property) — jamesSampica, Nov 04 '13 at 21:31
@Shoe - Not lying in Visual Tree doesn't make DP non-bindable. You can always bind with it using `Freezable` object or by storing object in `Tag` and binding from there. Also check this link out [here](http://blogs.msdn.com/b/jaimer/archive/2008/11/22/forwarding-the-datagrid-s-datacontext-to-its-columns.aspx). — Rohit Vats, Nov 04 '13 at 21:35
@Rohit it is non-bindable at the cell level. Yes, you can find a way to bind it at the column level. That's not what this question asks for. — jamesSampica, Nov 04 '13 at 21:37
@Shoe I copied the code from your answer and it works! Except that I can only input numbers, no letters. Is there any reason why that is that I am missing? — mastur cheef, Nov 04 '13 at 21:46

score 0 · Answer 1 · answered Nov 04 '13 at 21:50

Instead of using converter you can use DataTrigger to enable\disable DataGridCell:

<DataGridTextColumn Header="Name" Binding="{Binding GroupDescription}">
    <DataGridTextColumn.CellStyle>
        <Style TargetType="DataGridCell">
            <Style.Triggers>
                <DataTrigger Binding="{Binding Current}" Value="Current">
                    <Setter Property="TextBlock.IsEnabled" Value="False" />                                    
                </DataTrigger>                              
            </Style.Triggers>
        </Style>                       
    </DataGridTextColumn.CellStyle>
</DataGridTextColumn>

score 0 · Answer 2 · answered Nov 05 '13 at 10:51

The value of DataGridTextColumn's IsReadOnly property is a global value that will effects all cells. The individual cell doesn't has its own IsReadOnly property. Try create own DependencyProperty like this: http://blog.spencen.com/2009/04/25/readonly-rows-and-cells-in-a-datagrid.aspx

Binding IsReadOnly using IValueConverter

2 Answers2