Untitled

How to Bind Columns Property of a DataGrid Inside a UserControl?
<local:MyControl>
    <local:MyControl.GridColumns>
        <DataGridTextColumn Header="Id" />
    </local:MyControl.GridColumns>
</local:MyControl>

<UserControl ...>
    <DataGrid Columns={Binding GridColumns} />
</UserControl>

<DataGrid Name="datagrid" />

public ObservableCollection<DataGridColumn> Columns
{
    get { return datagrid.Columns; }
}