（一）C# Windows Mobile 半透明窗体

Windows Mobile，个人心中臻至完美的系统。

不忍自己对WM的钻研成果消逝，故留作纪念。

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系列开篇，便是一个曾令自己困扰很久的问题：如何实现半透明窗体。

如果了解Win32编程，其实很简单。

主要用到了三个方法：

SetLayeredWindowAttributes

GetWindowLong

SetWindowLong

核心代码：

private void SetWindowTransparent(byte bAlpha)
{
    SetWindowLong(this.Handle, (int)WindowStyle.GWL_EXSTYLE,
        GetWindowLong(this.Handle, (int)WindowStyle.GWL_EXSTYLE) | (uint)ExWindowStyle.WS_EX_LAYERED);

    SetLayeredWindowAttributes(this.Handle, 0, bAlpha, LWA_ALPHA);
}

效果：

完整代码：

using System;

using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace Demo01
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        [DllImport("coredll.dll")]
        public extern static IntPtr GetDesktopWindow();

        [DllImport("coredll.dll")]
        public extern static bool SetLayeredWindowAttributes(IntPtr hwnd, uint crKey, byte bAlpha, uint dwFlags);
        public static uint LWA_COLORKEY = 0x00000001;
        public static uint LWA_ALPHA = 0x00000002;

        [DllImport("coredll.dll")]
        public extern static uint SetWindowLong(IntPtr hwnd, int nIndex, uint dwNewLong);
        [DllImport("coredll.dll")]
        public extern static uint GetWindowLong(IntPtr hwnd, int nIndex);

        public enum WindowStyle : int
        {
            GWL_EXSTYLE = -20
        }

        public enum ExWindowStyle : uint
        {
            WS_EX_LAYERED = 0x00080000
        }

        private void SetWindowTransparent(byte bAlpha)
        {
            try
            {
                SetWindowLong(this.Handle, (int)WindowStyle.GWL_EXSTYLE,
                    GetWindowLong(this.Handle, (int)WindowStyle.GWL_EXSTYLE) | (uint)ExWindowStyle.WS_EX_LAYERED);

                SetLayeredWindowAttributes(this.Handle, 0, bAlpha, LWA_ALPHA);

            }
            catch
            {
            }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        private void trackBar1_ValueChanged(object sender, EventArgs e)
        {
            label1.Text = "透明度(0~255): " + trackBar1.Value.ToString();
            SetWindowTransparent(Convert.ToByte(trackBar1.Value));
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            Rectangle rf = Screen.PrimaryScreen.WorkingArea;

            this.Location = new Point((rf.Width - this.Width) / 2, (rf.Height - this.Height) / 2);

            //SetWindowTransparent(136);
        }
    }
}

工程文件：

https://files.cnblogs.com/files/lesliexin/01.%E5%8D%8A%E9%80%8F%E6%98%8E%E7%AA%97%E4%BD%93.7z

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