将窗体的父级设置为"FindWindow“

Question

我正在制作一个覆盖图。我在这里有这个代码

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


    namespace HyperBox
    {

public partial class Form1 : Form
{

    public Form1()
    {
        InitializeComponent();

        this.TopMost = true; // make the form always on top
        this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None; // hidden border
        this.WindowState = FormWindowState.Maximized; // maximized
        this.MinimizeBox = this.MaximizeBox = false; // not allowed to be minimized
        this.MinimumSize = this.MaximumSize = this.Size; // not allowed to be resized
        this.TransparencyKey = this.BackColor = Color.Red; // the color key to transparent, choose a color that you don't use

        // Set the form click-through
        int initialStyle = GetWindowLong(this.Handle, -20);
        SetWindowLong(this.Handle, -20, initialStyle | 0x80000 | 0x20);
    }

    [System.Runtime.InteropServices.DllImport("user32.dll", SetLastError = true)]
    static extern int GetWindowLong(IntPtr hWnd, int nIndex);

    [System.Runtime.InteropServices.DllImport("user32.dll")]
    static extern int SetWindowLong(IntPtr hWnd, int nIndex, int dwNewLong);
    [System.Runtime.InteropServices.DllImport("user32.dll")]
    static extern bool SetLayeredWindowAttributes(IntPtr hwnd, uint crKey, byte bAlpha,         uint dwFlags);
    [System.Runtime.InteropServices.DllImport("user32.dll")]
    static extern int SetParent(int hWndChild, int hWndNewParent);


    protected override void OnPaint(PaintEventArgs e)
    {
        base.OnPaint(e);
        // draw what you want
        e.Graphics.FillEllipse(Brushes.Blue, 30, 30, 100, 100);

    }
    private void Form1_MouseMove(object sender, MouseEventArgs e)
    {

    }

    private void Form1_Paint(object sender, PaintEventArgs e)
    {

    }

    private void Form1_Load(object sender, EventArgs e)
    {

    }



}

    }

它在窗体上绘制一个椭圆，该窗体是透明的并且始终在顶部。问题是，它不能在全屏上工作。

我试过用这个

    SetParent(this.handle, FindWindow(null, "<parent window title here>"));

除了我得到了错误。有没有人能帮帮忙？

Answer 1

我相信你的错误就在这里

[System.Runtime.InteropServices.DllImport("user32.dll")]
static extern int SetParent(int hWndChild, int hWndNewParent);

它需要两个IntPtr类型的参数，而不是int类型，并且它返回的是IntPtr，而不是int。

MSDN提供了更多信息。有关一些好的C#示例，请参阅底部的用户贡献。

请记住，当与DllImport一起使用时，extern是对非托管代码的引用。在user32.dll中名为SetParent()的方法没有接受两个int作为参数的定义。

因此该块应为：

[System.Runtime.InteropServices.DllImport("user32.dll")]
static extern IntPtr SetParent(IntPtr hWndChild, IntPtr hWndNewParent);