c# winform窗口一直置顶显示在桌面最上方或最底层的方法-526互联

方法一：调用Windows API来实现窗口置顶。

1.使用命名空间

using System.Runtime.InteropServices;

2、声明Windonws API方法

[DllImport("user32.dll", EntryPoint = "SetWindowPos")]
public static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int X, int Y, int cx, int cy, uint uFlags);

public const uint SWP_NOMOVE = 0x2;
public const uint SWP_NOSIZE = 0x1;
public static readonly IntPtr HWND_TOPMOST = new IntPtr(-1);
public static readonly IntPtr HWND_NOTOPMOST = new IntPtr(-2);

3、调用方法

SetWindowPos(this.Handle, HWND_TOPMOST, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE);//窗口置顶

SetWindowPos(this.Handle, HWND_NOTOPMOST, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE);//窗口置底

方法二：使用TopMost属性实现

this.TopMost = true;//窗口置顶

this.TopMost = false;//取消窗口置顶

示例代码

using System;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        [DllImport("user32.dll", EntryPoint = "SetWindowPos")]
        public static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int X, int Y, int cx, int cy, uint uFlags);

        public const uint SWP_NOMOVE = 0x2;
        public const uint SWP_NOSIZE = 0x1;
        public static readonly IntPtr HWND_TOPMOST = new IntPtr(-1);
        public static readonly IntPtr HWND_NOTOPMOST = new IntPtr(-2);

        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            //将窗口置顶
            SetWindowPos(this.Handle, HWND_TOPMOST, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE);
        }

        private void button2_Click(object sender, EventArgs e)
        {
            //将窗口置底
            SetWindowPos(this.Handle, HWND_NOTOPMOST, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE);
        }

        private void Form1_FormClosing(object sender, FormClosingEventArgs e)
        {
            //在窗口关闭时，取消TopMost属性
            this.TopMost = false;
        }
    }
}