How to fit Window to any screen resolution in WPF ?

Horizontal Alignment Property is used to align controls horizontally. It has 4 options.
1. Left
2. Center
3. Right
4. Stretch

Like above, Vertical Alignment Property is used to align controls vertically. It also has 4 options.
1. Top
2. Center
3. Bottom
4. Stretch

Margin property used to specify the distance for the control from Left, Top, Right, Bottom corners. The above properties are very important in placing controls in a WPF window.

I'll explain this with small example. Consider a button inside the window.

<Button Content="Button" Height="Auto" Width="Auto" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Margin="150,140,150,140"/>

Here, HorizontalAlignment is set to Stretch, it means, the button will be stretched to fit when the window is resized. This is same for VerticalAlignment property.

Margin: Left = 150, Top = 140, Right = 150, Bottom = 140 - these margin values placing the button 140 pixel distance from Top and Bottom, also places the button 150 pixel distance from Left and Right.

Now if your resizes the screen, the button will be placed according to the margin, and the button wil be stretched to fit the window.

if you are hosting your wpf app inside another window that is your main window is in different file then to wrap data inside it use viewbox with Stretch property equal to "Fill".
the whole data will wrapped according to size of window.