Prevent Double-Click Maximization on RadWindow

Updated on Sep 15, 2025

Environment

Product Version	2021.3.914
Product	RadWindow for WPF

Description

How to prevent maximization on the RadWindow control, when the title bar is double-clicked.

Solution

To achieve this, you could subscribe to the HostCreated event of the Window control, and inside of it, set the SourceInitialized event of the HostWindow property provided by the HostWindowCreatedEventArgs event arguments. Additionally, several fields and methods from the Win32 API would be required, which are present in the below code snippet.

C#

	public partial class MainWindow : RadWindow
	{
		public MainWindow()
		{
			InitializeComponent();
	
			this.HostCreated += MainWindow_HostCreated;
		}
		
		[DllImport("user32.dll")]
		private static extern int GetWindowLong(IntPtr hWnd, int nIndex);
		[DllImport("user32.dll")]
		private static extern int SetWindowLong(IntPtr hWnd, int nIndex, int dwNewLong);
	
		private const int GWL_STYLE = -16;
		private const int WS_MAXIMIZEBOX = 0x10000;
		
		private void MainWindow_HostCreated(object sender, HostWindowCreatedEventArgs e)
		{
			e.HostWindow.SourceInitialized += Window_SourceInitialized;
		}
	
		private void Window_SourceInitialized(object sender, EventArgs e)
		{
			IntPtr hwnd = new WindowInteropHelper((Window)sender).Handle;
			var value = GetWindowLong(hwnd, GWL_STYLE);
			SetWindowLong(hwnd, GWL_STYLE, (int)(value & ~WS_MAXIMIZEBOX));
		}
	}

VB.NET

	Public Partial Class MainWindow
		Inherits RadWindow
	
		Public Sub New()
			InitializeComponent()
			Me.HostCreated += AddressOf MainWindow_HostCreated
		End Sub
	
		<DllImport("user32.dll")>
		Private Shared Function GetWindowLong(ByVal hWnd As IntPtr, ByVal nIndex As Integer) As Integer
		<DllImport("user32.dll")>
		Private Shared Function SetWindowLong(ByVal hWnd As IntPtr, ByVal nIndex As Integer, ByVal dwNewLong As Integer) As Integer
		Private Const GWL_STYLE As Integer = -16
		Private Const WS_MAXIMIZEBOX As Integer = &H10000
	
		Private Sub MainWindow_HostCreated(ByVal sender As Object, ByVal e As HostWindowCreatedEventArgs)
			e.HostWindow.SourceInitialized += AddressOf Window_SourceInitialized
		End Sub
	
		Private Sub Window_SourceInitialized(ByVal sender As Object, ByVal e As EventArgs)
			Dim hwnd As IntPtr = New WindowInteropHelper(CType(sender, Window)).Handle
			Dim value = GetWindowLong(hwnd, GWL_STYLE)
			SetWindowLong(hwnd, GWL_STYLE, CInt((value And Not WS_MAXIMIZEBOX)))
		End Sub
	End Class