Question

I want to make my checkbox in datatemplate has threestates I implemented a function to set datatemplate of listview columns as checkbox : but I want it to allow threestates

public DataTemplate SampleTemplate()
{
    DataTemplate dt = new System.Windows.DataTemplate();
    dt.DataType = typeof(bool);
    FrameworkElementFactory fef = new FrameworkElementFactory(typeof(CheckBox));
    Binding bd = new Binding("EnabledThreading");
    fef.SetBinding(CheckBox.IsCheckedProperty, bd);
    dt.VisualTree = fef;
    return dt;
} 

Answer 1

Set the respective property, something along the lines of:

fef.SetValue(CheckBox.IsThreeStateProperty, true);

(FrameworkElementFactory is deprecated by the way if you did not notice)