如何使平面窗口可调整大小？答案

【问题标题】：How can I make a flat window resizable?如何使平面窗口可调整大小？
【发布时间】：2019-01-25 16:32:51
【问题描述】：

背景：

你好。我目前正在尝试在 Windows 窗体中为学校项目制作自定义平面样式窗口。这个想法是使用这个窗口作为基础并创建其他继承自它的窗口。我想要实现的风格类似于 Visual Studio 2017 本身（深色主题）。我正在尝试向窗口添加功能，例如：

双击顶部面板可最大化窗口（完成）。
用顶部面板拖动窗口（完成）。
焦点/取消焦点时边框颜色变化（完成）。

当试图通过拖动边框来调整窗口大小时，问题就出现了。

我有什么：

这是window 的图片。

表单有 2 个面板：

顶部面板：作为窗口图标、窗口名称标签和 3 个按钮（最小化、最大化和关闭）。
主面板：它是一个空面板，这是窗口内容所在的位置。

表单有 1px 的内边距（变色边框，稍后会出现）

问题：

我发现这个答案似乎可以解决我的问题：https://stackoverflow.com/a/32261547/70345 但是当我尝试实现它时，它并不能完全起作用。人们似乎做的是在表单周围绘制矩形，并在 WndProc 函数中检测光标是否悬停在它们上方：

protected override void OnPaint(PaintEventArgs e) // you can safely omit this method if you want
{
    e.Graphics.FillRectangle(Brushes.Green, Top);
    e.Graphics.FillRectangle(Brushes.Green, Left);
    e.Graphics.FillRectangle(Brushes.Green, Right);
    e.Graphics.FillRectangle(Brushes.Green, Bottom);
}

private const int
    HTLEFT = 10,
    HTRIGHT = 11,
    HTTOP = 12,
    HTTOPLEFT = 13,
    HTTOPRIGHT = 14,
    HTBOTTOM = 15,
    HTBOTTOMLEFT = 16,
    HTBOTTOMRIGHT = 17;

const int _ = 10; // you can rename this variable if you like

Rectangle Top { get { return new Rectangle(0, 0, this.ClientSize.Width, _); } }
Rectangle Left { get { return new Rectangle(0, 0, _, this.ClientSize.Height); } }
Rectangle Bottom { get { return new Rectangle(0, this.ClientSize.Height - _, this.ClientSize.Width, _); } }
Rectangle Right { get { return new Rectangle(this.ClientSize.Width - _, 0, _, this.ClientSize.Height); } }

Rectangle TopLeft { get { return new Rectangle(0, 0, _, _); } }
Rectangle TopRight { get { return new Rectangle(this.ClientSize.Width - _, 0, _, _); } }
Rectangle BottomLeft { get { return new Rectangle(0, this.ClientSize.Height - _, _, _); } }
Rectangle BottomRight { get { return new Rectangle(this.ClientSize.Width - _, this.ClientSize.Height - _, _, _); } }


protected override void WndProc(ref Message message)
{
    base.WndProc(ref message);

    if (message.Msg == 0x84) // WM_NCHITTEST
    {
        var cursor = this.PointToClient(Cursor.Position);

        if (TopLeft.Contains(cursor)) message.Result = (IntPtr)HTTOPLEFT;
   else if (TopRight.Contains(cursor)) message.Result = (IntPtr)HTTOPRIGHT;
   else if (BottomLeft.Contains(cursor)) message.Result = (IntPtr)HTBOTTOMLEFT;
   else if (BottomRight.Contains(cursor)) message.Result = (IntPtr)HTBOTTOMRIGHT;

   else if (Top.Contains(cursor)) message.Result = (IntPtr)HTTOP;
   else if (Left.Contains(cursor)) message.Result = (IntPtr)HTLEFT;
   else if (Right.Contains(cursor)) message.Result = (IntPtr)HTRIGHT;
   else if (Bottom.Contains(cursor)) message.Result = (IntPtr)HTBOTTOM;
    }
}}

但是当我这样做时，矩形被绘制在面板后面，所以即使我将矩形的大小（“_”变量）设置为 10 像素或 20 像素，我可以单击以调整窗口大小的区域始终是 1 像素（因为表单填充）。

我还尝试使用某种叠加层并在那里绘制矩形：https://www.codeproject.com/Articles/26071/Draw-Over-WinForms-Controls

但我遇到了同样的问题。

我需要什么：

我需要以某种方式在面板前面绘制矩形，这样我就可以有更大的区域来调整表单的大小。我在编程方面不是很有经验，所以我愿意接受任何建议和改进。也欢迎其他解决方案。

这是我的表格：

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

namespace BaseWindow
{
    public partial class BaseWindowForm : Form
    {
        public BaseWindowForm()
        {
            InitializeComponent();
        }

        #region draggable window
        private bool windowDragging = false;
        private Point startPoint = new Point(0, 0);

        private void TopPanel_MouseDown(object sender, MouseEventArgs e)
        {
            windowDragging = true;  // _dragging is your variable flag
            startPoint = new Point(e.X, e.Y);
        }

        private void TopPanel_MouseUp(object sender, MouseEventArgs e)
        {
            windowDragging = false;
        }

        private void TopPanel_MouseMove(object sender, MouseEventArgs e)
        {
            if (windowDragging)
            {
                Point p = PointToScreen(e.Location);
                Location = new Point(p.X - this.startPoint.X, p.Y - this.startPoint.Y);
            }
        }
        #endregion

        #region border color focus
        private void BaseWindowForm_Activated(object sender, EventArgs e)
        {
            this.BackColor = Color.FromArgb(0, 122, 204);
        }

        private void BaseWindowForm_Deactivate(object sender, EventArgs e)
        {
            this.BackColor = Color.FromArgb(63, 63, 70);
        }
        #endregion

        #region maximize/minimize
        private void BaseWindowForm_Maximize(object sender, EventArgs e)
        {
            if (this.WindowState == FormWindowState.Normal)
            {
                this.WindowState = FormWindowState.Maximized;
            }
            else if (this.WindowState == FormWindowState.Maximized)
            {
                this.WindowState = FormWindowState.Normal;
            }
        }

        private void ButtonMinimize_Click(object sender, EventArgs e)
        {
            this.WindowState = FormWindowState.Minimized;
        }
        #endregion

        private const int
            HTLEFT = 10,
            HTRIGHT = 11,
            HTTOP = 12,
            HTTOPLEFT = 13,
            HTTOPRIGHT = 14,
            HTBOTTOM = 15,
            HTBOTTOMLEFT = 16,
            HTBOTTOMRIGHT = 17;

        const int _ = 10; // you can rename this variable if you like

        Rectangle Top { get { return new Rectangle(0, 0, this.ClientSize.Width, _); } }
        Rectangle Left { get { return new Rectangle(0, 0, _, this.ClientSize.Height); } }
        Rectangle Bottom { get { return new Rectangle(0, this.ClientSize.Height - _, this.ClientSize.Width, _); } }
        Rectangle Right { get { return new Rectangle(this.ClientSize.Width - _, 0, _, this.ClientSize.Height); } }

        Rectangle TopLeft { get { return new Rectangle(0, 0, _, _); } }
        Rectangle TopRight { get { return new Rectangle(this.ClientSize.Width - _, 0, _, _); } }
        Rectangle BottomLeft { get { return new Rectangle(0, this.ClientSize.Height - _, _, _); } }
        Rectangle BottomRight { get { return new Rectangle(this.ClientSize.Width - _, this.ClientSize.Height - _, _, _); } }


        protected override void WndProc(ref Message message)
        {
            base.WndProc(ref message);

            if (message.Msg == 0x84) // WM_NCHITTEST
            {
                var cursor = this.PointToClient(Cursor.Position);

                if (TopLeft.Contains(cursor)) message.Result = (IntPtr)HTTOPLEFT;
                else if (TopRight.Contains(cursor)) message.Result = (IntPtr)HTTOPRIGHT;
                else if (BottomLeft.Contains(cursor)) message.Result = (IntPtr)HTBOTTOMLEFT;
                else if (BottomRight.Contains(cursor)) message.Result = (IntPtr)HTBOTTOMRIGHT;

                else if (Top.Contains(cursor)) message.Result = (IntPtr)HTTOP;
                else if (Left.Contains(cursor)) message.Result = (IntPtr)HTLEFT;
                else if (Right.Contains(cursor)) message.Result = (IntPtr)HTRIGHT;
                else if (Bottom.Contains(cursor)) message.Result = (IntPtr)HTBOTTOM;
            }
        }
    }
}

如果您需要更多详细信息，可以在此处下载源代码：https://github.com/RndmDud/FormBaseWindow

【问题讨论】：

标签： c# winforms

【解决方案1】：

您可以增加表单填充（将其设置为 ex: 2,2,2,2）请检查:(Can't resize a borderless winform from top because of a docked panel)

编辑：

在与@Outman 建议更改边框颜色相同的链接中：

        protected override void OnPaintBackground(PaintEventArgs e)
    {
        base.OnPaintBackground(e);            //comment this out to prevent default painting 
        using (SolidBrush brush = new SolidBrush(Color.FromArgb(45, 45, 48))) //any color you like  }
        {
            e.Graphics.FillRectangle(brush, e.ClipRectangle);
        }
    }

【讨论】：