How might I accomplish this? I'm using the MVVM pattern. I can't bind to FieldLayouts property because it's read only. How would I clear the FieldLayouts collection in the view model?

Hi KrisVice,

You can setup an attached property and bind to a property in your viewmodel.  Just before you update the datasource in the viewmodel, set this property so that it triggers the attached property.  Inside the attached property it can clear the layouts.  Like this:

public class DataGridBehaviors
{
    public static bool GetClearFieldLayouts(DependencyObject obj)
    {
        return (bool)obj.GetValue(ClearFieldLayoutsProperty);
    }

    public static void SetClearFieldLayouts(DependencyObject obj, bool value)
    {
        obj.SetValue(ClearFieldLayoutsProperty, value);
    }

    // Using a DependencyProperty as the backing store for ClearFieldLayouts. This enables animation, styling, binding, etc...
    public static readonly DependencyProperty ClearFieldLayoutsProperty =
        DependencyProperty.RegisterAttached("ClearFieldLayouts", typeof(bool), typeof(DataGridBehaviors), new PropertyMetadata(false, OnClearFieldLayoutsChanged));

    private static void OnClearFieldLayoutsChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var dataGrid = d as XamDataGrid;
        var result = (bool)e.NewValue;
        if (result)
        {
            dataGrid.FieldLayouts.Clear();
            SetClearFieldLayouts(dataGrid, false);
        }
    }
}

Here is the viewmodel property:

private bool _clearFieldLayouts;
public bool ClearFieldLayouts
{
    get { return _clearFieldLayouts; }
    set
    {
        if (value)
        {
            _clearFieldLayouts = true;
            OnPropertyChanged("ClearFieldLayouts");
            _clearFieldLayouts = false;
        }
    }
}

Then just bind it up:

<igDP:XamDataGrid ... local:DataGridBehaviors.ClearFieldLayouts="{Binding Path=ClearFieldLayouts, Mode=TwoWay}">