C#-- Hollow form design

Features

1. Draw a hollow form
2. The buttons on the form are not transparent

1. Introduction

Hollowed form, although transparent form can be realized, it does not realize transparency in the true sense. Click the form to click the form behind the form.

2. Effect display

Three, code implementation

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

namespace 通用测试平台
{
    public partial class Form1 : Form
    {
        #region 变量
        private const uint WS_EX_LAYERED = 0x80000;
        private const int GWL_EXSTYLE = -20;
        private const int LWA_COLORKEY = 1;
        [DllImport("user32", EntryPoint = "SetWindowLong")]
        private static extern uint SetWindowLong(IntPtr hwnd, int nIndex, uint dwNewLong);
        [DllImport("user32", EntryPoint = "SetLayeredWindowAttributes")]
        private static extern int SetLayeredWindowAttributes(IntPtr hwnd, int crKey, int bAlpha, int dwFlags);
        #endregion
        #region 构造函数
        public Form1()
        {
            InitializeComponent();
            SetWindowLong(Handle, GWL_EXSTYLE, WS_EX_LAYERED);
            SetLayeredWindowAttributes(Handle, 0x00FF00, 255, LWA_COLORKEY);
        }
        #endregion
        #region 窗体初始化
        private void Form1_Load(object sender, EventArgs e)
        {
            //开启透明窗体
            TransparencyKey = BackColor;
        } 
        #endregion
    }
}