WPF sets the size of a form that can be dragged with the mouse

This example shows how WPF sets the size of a form that can be dragged with the mouse. Share to everybody for everybody reference. Specific implementation methods are as follows:

private void Window_Loaded(object sender, RoutedEventArgs e)

{

    //  Gets the form handle  

    IntPtr hwnd = new System.Windows.Interop.WindowInteropHelper(this).Handle;
    //  Get form's   style  

    int oldstyle = NativeMethods.GetWindowLong(hwnd, NativeMethods.GWL_STYLE);
    //  Change the style of the form to a bezel-less form  

    NativeMethods.SetWindowLong(hwnd, NativeMethods.GWL_STYLE, oldstyle & ~NativeMethods.WS_CAPTION);
    // SetWindowLong(hwnd, GWL_EXSTYLE, oldstyle & ~WS_EX_LAYERED); 

    // 1 | 2 << 8 | 3 << 16  r=1,g=2,b=3  As shown in the winuse.h file  

    //  Set the form to be transparent  

    NativeMethods.SetLayeredWindowAttributes(hwnd, 1 | 2 << 8 | 3 << 16, 0, NativeMethods.LWA_ALPHA);
    //  Create a rounded form   12  This value can be set according to its own project  

    NativeMethods.SetWindowRgn(hwnd, NativeMethods.CreateRoundRectRgn(0, 0, Convert.ToInt32(this.ActualWidth), Convert.ToInt32(this.ActualHeight), 12, 12), true); 

}

NativeMethods. cs code:

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

 

namespace SEsoft

{

    public class NativeMethods

    {

        /// <summary> 

        ///  With an outer border and a title windows The style of the  

        /// </summary> 

        public const int WS_CAPTION = 0X00C0000;

 

        /// <summary> 

        /// window  Extension style   Hierarchical display  

        /// </summary> 

        public const int WS_EX_LAYERED = 0x00080000;

 

        /// <summary> 

        ///  with alpha The style of the  

        /// </summary> 

        public const int LWA_ALPHA = 0x00000002;

 

        /// <summary> 

        ///  Color Settings  

        /// </summary> 

        public const int LWA_COLORKEY = 0x00000001;

 

        /// <summary> 

        /// window Basic style of  

        /// </summary> 

        public const int GWL_STYLE = -16;

 

        /// <summary> 

        /// window Extended style of  

        /// </summary> 

        public const int GWL_EXSTYLE = -20;

 

        /// <summary> 

        ///  Sets the style of the form  

        /// </summary> 

        /// <param name="handle"> Handle to the action form </param> 

        /// <param name="oldStyle"> Sets the style type of the form .</param> 

        /// <param name="newStyle"> New style </param> 

        [System.Runtime.InteropServices.DllImport("User32.dll")]

        public static extern void SetWindowLong(IntPtr handle, int oldStyle, int newStyle);

 

        /// <summary> 

        ///  Gets the style specified by the form . 

        /// </summary> 

        /// <param name="handle"> Handle to the action form </param> 

        /// <param name="style"> The style to return </param> 

        /// <returns> The current window The style of the </returns> 

        [System.Runtime.InteropServices.DllImport("User32.dll")]

        public static extern int GetWindowLong(IntPtr handle, int style);

 

        /// <summary> 

        ///  Sets the work area of the form . 

        /// </summary> 

        /// <param name="handle"> Handle to the action form .</param> 

        /// <param name="handleRegion"> Handle to manipulate the form region .</param> 

        /// <param name="regraw">if set to <c>true</c> [regraw].</param> 

        /// <returns> The return value </returns> 

        [System.Runtime.InteropServices.DllImport("User32.dll")]

        public static extern int SetWindowRgn(IntPtr handle, IntPtr handleRegion, bool regraw);

 

        /// <summary> 

        ///  Create an area with rounded corners . 

        /// </summary> 

        /// <param name="x1"> Top-left coordinate X value .</param> 

        /// <param name="y1"> Top-left coordinate Y value .</param> 

        /// <param name="x2"> Of the lower right hand corner X value .</param> 

        /// <param name="y2"> Of the lower right hand corner Y value .</param> 

        /// <param name="width"> Oval with rounded corners width.</param> 

        /// <param name="height"> Oval with rounded corners height.</param> 

        /// <returns>hRgn The handle of </returns> 

        [System.Runtime.InteropServices.DllImport("gdi32.dll")]

        public static extern IntPtr CreateRoundRectRgn(int x1, int y1, int x2, int y2, int width, int height);

 

        /// <summary> 

        /// Sets the layered window attributes. 

        /// </summary> 

        /// <param name="handle"> Handle to the window to operate on </param> 

        /// <param name="colorKey">RGB The value of the </param> 

        /// <param name="alpha">Alpha The value of transparency </param> 

        /// <param name="flags"> With parameters </param> 

        /// <returns>true or false</returns> 

        [System.Runtime.InteropServices.DllImport("User32.dll")]

        public static extern bool SetLayeredWindowAttributes(IntPtr handle, uint colorKey, byte alpha, int flags);

    }

}

I hope this article has been helpful for your WPF programming.