<DataGridTemplateColumn.Header>
     <CheckBox x:Name="chk_Top" HorizontalAlignment="Center" HorizontalContentAlignment="Center"
         Command="{Binding Chk_GridTop}"/>
 </DataGridTemplateColumn.Header>

public partial class ViewModel_AC: INotifyPropertyChanged
    ICommand _chkGridTop;
    public ICommand Chk_GridTop
        get { return _chkGridTop ?? (_chkGridTop = new DelegateCommand(_chk_GridTop)); }
    public void _chk_GridTop(object check)
     //Empty
}

public class DelegateCommand : ICommand
    readonly Action<object> _execute;
    readonly Predicate<object> _canExecute;
    public DelegateCommand(Action<object> execute, Predicate<object> canExecute)
        if (execute == null)
            throw new NullReferenceException("execute can no null");
        _execute = execute;
        _canExecute = canExecute;
    public DelegateCommand(Action<object> execute) : this(execute, null)
    public event EventHandler CanExecuteChanged
        add { CommandManager.RequerySuggested += value; }
        remove { CommandManager.RequerySuggested -= value; }
    public bool CanExecute(object parameter)
        return _canExecute == null ? true : _canExecute(parameter);
    public void Execute(object parameter)