As the columns of a data grid aren\'t in the visual tree of datagrid I\'m m using this approach of Binding Proxy to bind Visibility of a DataGridTextColumn.
DataGridTextColumn
The type of the Width property of a DataGridColumn is DataGridLength and not double.
Width
DataGridColumn
DataGridLength
double
Change type of your source property:
public DataGridLength Width { get { return m_width; } set { m_width = value; OnPropertyChanged("Width"); } } DataGridLength m_width;
And the Mode of the Binding:
Mode
Binding