Focus on control from viewModel

In wpf we should not access any UI control in viewmodel then how can we focus on control any such condition . below is solution for the same.


First create a attached property.

 public static class FocusExt
    {
        public static bool GetIsFocused(DependencyObject obj)
        {
            return (bool)obj.GetValue(IsFocusedProperty);
        }


        public static void SetIsFocused(DependencyObject obj, bool value)
        {
            obj.SetValue(IsFocusedProperty, value);
        }


        public static readonly DependencyProperty IsFocusedProperty =
            DependencyProperty.RegisterAttached(
             "IsFocused", typeof(bool), typeof(FocusExt),
             new UIPropertyMetadata(false, OnIsFocusedPropertyChanged));


        private static void OnIsFocusedPropertyChanged(DependencyObject d,
            DependencyPropertyChangedEventArgs e)
        {
            var uie = (UIElement)d;
            if ((bool)e.NewValue)
            {
                uie.Focus();
            }
        }
    }




First add namastace inb XAML like.
xmlns:utility="clr-namespace:NPOS.Utility"


then create a property in Model.
 private bool isControlFocused;

        public bool IsControlFocused
        {
            get { return isControlFocused; }
            set { isControlFocused = value; OnPropertyChanged("IsControlFocused"); }
        }


and set it to true in ViewModel.
Model.IsControlFocused = true;

and finally bind this property ib View.
 <TextBox utility:FocusExt.IsFocused="{Binding Model.IsControlFocused}"/>