c#如何手动改变自制无边框Windows窗体的大小？

当用户去除窗体边框时，自行设置窗体外观，用户就不能对窗体的大小进行随意改变了，下面，济南网站建设小编就来为大家介绍，怎么在c#编程语言中手动改天无边框窗体的大小，有需要的朋友可以过来参考一下。

关键代码：

using System;

using System.Drawing;

using System.Windows.Forms;

public partial class FrmMain : Form

{

    private const int RESIZE_HANDLE_SIZE = 10;

    private Timer resizeTimer;

    private Size targetSize;

    public FrmMain()

    {

        InitializeComponent();

        this.FormBorderStyle = FormBorderStyle.None;

        this.MinimumSize = new Size(400, 300);

        resizeTimer = new Timer();

        resizeTimer.Interval = 10;

        resizeTimer.Tick += ResizeTimer_Tick;

        // 添加测试按钮

        Button btnMax = new Button();

        btnMax.Text = "最大化";

        btnMax.Location = new Point(10, 10);

        btnMax.Click += BtnMax_Click;

        this.Controls.Add(btnMax);

        Button btnRestore = new Button();

        btnRestore.Text = "恢复";

        btnRestore.Location = new Point(120, 10);

        btnRestore.Click += BtnRestore_Click;

        this.Controls.Add(btnRestore);

    }

    private void BtnMax_Click(object sender, EventArgs e)

    {

        AnimateResize(Screen.PrimaryScreen.WorkingArea.Size);

    }

    private void BtnRestore_Click(object sender, EventArgs e)

    {

        AnimateResize(new Size(800, 600));

    }

    private void ResizeTimer_Tick(object sender, EventArgs e)

    {

        Size current = this.Size;

        int step = 10;

        if (Math.Abs(current.Width - targetSize.Width) < step && 

            Math.Abs(current.Height - targetSize.Height) < step)

        {

            this.Size = targetSize;

            resizeTimer.Stop();

        }

        else

        {

            int newWidth = current.Width + Math.Sign(targetSize.Width - current.Width) * step;

            int newHeight = current.Height + Math.Sign(targetSize.Height - current.Height) * step;

            this.Size = new Size(newWidth, newHeight);

        }

    }

    private void AnimateResize(Size newSize)

    {

        targetSize = newSize;

        resizeTimer.Start();

    }

    protected override void WndProc(ref Message m)

    {

        const int WM_NCHITTEST = 0x0084;

        const int HTLEFT = 10;

        const int HTRIGHT = 11;

        const int HTTOP = 12;

        const int HTTOPLEFT = 13;

        const int HTTOPRIGHT = 14;

        const int HTBOTTOM = 15;

        const int HTBOTTOMLEFT = 16;

        const int HTBOTTOMRIGHT = 17;

        if (m.Msg == WM_NCHITTEST)

        {

            Point pos = new Point(m.LParam.ToInt32() & 0xffff, m.LParam.ToInt32() >> 16);

            pos = this.PointToClient(pos);

            if (pos.X < RESIZE_HANDLE_SIZE && pos.Y < RESIZE_HANDLE_SIZE)

                m.Result = (IntPtr)HTTOPLEFT;

            else if (pos.X >= this.ClientSize.Width - RESIZE_HANDLE_SIZE && pos.Y < RESIZE_HANDLE_SIZE)

                m.Result = (IntPtr)HTTOPRIGHT;

            else if (pos.X < RESIZE_HANDLE_SIZE && pos.Y >= this.ClientSize.Height - RESIZE_HANDLE_SIZE)

                m.Result = (IntPtr)HTBOTTOMLEFT;

            else if (pos.X >= this.ClientSize.Width - RESIZE_HANDLE_SIZE && pos.Y >= this.ClientSize.Height - RESIZE_HANDLE_SIZE)

                m.Result = (IntPtr)HTBOTTOMRIGHT;

            else if (pos.X < RESIZE_HANDLE_SIZE)

                m.Result = (IntPtr)HTLEFT;

            else if (pos.X >= this.ClientSize.Width - RESIZE_HANDLE_SIZE)

                m.Result = (IntPtr)HTRIGHT;

            else if (pos.Y < RESIZE_HANDLE_SIZE)

                m.Result = (IntPtr)HTTOP;

            else if (pos.Y >= this.ClientSize.Height - RESIZE_HANDLE_SIZE)

                m.Result = (IntPtr)HTBOTTOM;

            else

                m.Result = (IntPtr)HTCLIENT;

            return;

        }

        base.WndProc(ref m);

    }

    protected override void onPaint(PaintEventArgs e)

    {

        base.onPaint(e);

        ControlPaint.DrawSizeGrip(e.Graphics, this.BackColor, 

            this.ClientSize.Width - RESIZE_HANDLE_SIZE, 

            this.ClientSize.Height - RESIZE_HANDLE_SIZE, 

            RESIZE_HANDLE_SIZE, RESIZE_HANDLE_SIZE);

    }

}