WPF : How To Set Focus on another window (MVVM)

 How To Set Focus on another window (MVVM)?

I have two window (Parent-Child). Parent window opens Child window so child window is focused
(i.e. top most window) but when child replies to Parent, Parent window is not focused (i.e. it's not on top).

I have created a attached property in a separate class like:

class FocusAttched:DependencyObject
    {
        public static DependencyProperty IsFocusedProperty =
            DependencyProperty.RegisterAttached("IsFocused", typeof(bool), typeof(FocusAttched),
                new UIPropertyMetadata(false, OnIsFocusedChanged));
        public static bool GetIsFocused(DependencyObject dependencyObject)
        {
            return (bool)dependencyObject.GetValue(IsFocusedProperty);
        }
        public static void SetIsFocused(DependencyObject dependencyObject, bool value)
        {
            dependencyObject.SetValue(IsFocusedProperty, value);
        }
        public static void OnIsFocusedChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs dependencyPropertyChangedEventArgs)
        {
            ((FrameworkElement)dependencyObject).Focus(); //My Code-Niranjan
           
            // Removing hard coding
            //TextBox textBox = dependencyObject as TextBox;
            //bool newValue = (bool)dependencyPropertyChangedEventArgs.NewValue;
            //bool oldValue = (bool)dependencyPropertyChangedEventArgs.OldValue;
            //if (newValue && !oldValue && !textBox.IsFocused) textBox.Focus();
        }
    }

Now Attached this property to Parent window control (textbox)

                      VerticalScrollBarVisibility="Visible" TextWrapping="Wrap" AcceptsReturn="True" HorizontalAlignment="Left"
                 Height="248" Margin="191,36,0,0"   VerticalAlignment="Top" Width="249"/>

I am binding this attached property with a new property in View Model, for this reason I am creating a new bool property in View model.

bool _setFoucs;
        public bool SetFocus {
            get { return _setFoucs; }
            set { _setFoucs = value; OnPropertyChanged(nameof(SetFocus)); }
        }

I will set this property in Callback method.

Summery : Idea is that when Child window sends a message to Parent window, callback method will get called by Child, in this Callback I am setting this 'SetFocus' Property which is attached to TextBox of Parent window, OnPropertyChnage callback of Attached/Dependency property I am calling Focus() method of FrameworkElement( TextBox is Framework element).

WPF - Difference between ContentControl and ContentPresenter?

Difference between ContentControl and ContentPresenter?


ContentPresenter is a lightweight element. It's derived from FrameworkElements class. So, It has no Template property (i.e.) we can't set control Template for it, while we can set data template for it as it has Content property.

ContentPresenter has a addition property 'ContentSource' which is not present in Content Control.

Default value of 'ContentSource' property is content, So when we will put ContentPresenter inside of ControlTemplate we don't need to define binding explicitly.

ContentControl also uses ContentPrenseter in it's template to display data.

WPF - How to print Parent hierarchy of an element?

How to print Parent hierarchy of an element?

            DependencyObject _parent = myGrid.Parent;
            while (_parent != null)
            {
                System.Diagnostics.Debug.WriteLine(_parent);
                _parent = ((FrameworkElement)_parent)?.Parent;
            }

Every framework element has a Parent property, we can loop through like above code and print parent of particular element.

WCF : How to transfer large data via wcf service?

How to transfer large data from wcf service?

To transfer large data from wcf service, we need to change some configuration settings like:

MaxReceivedMessageSize
Transfer Mode
Max Depth (in ReaderQuotas)
MaxArrayLength

Above are necessary settings to transfer large data form WCF, apart from these settings, to increase performance you can change message encoding to "MTOM".

Complete binding configuration is :
 

    
Note : you need these settings in both Service and application config file (web.config and app.config).