一个问题搞了一个星期了，大家给看下

有个方式看你适不适用
把 GroupBox 的背景色改成比如红色
把 Form 的 TransparentKey 属性设成红色
这样子 GroupBox 的背景就变透明了~

对控件使用REGION就能解决所有控件的透明问题。
好好研究下，
如果不懂，
还可以再留言给我

补充  代码如下using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Drawing.Drawing2D;namespace SNfox.Foundation.ControlEx
{
    [ToolboxBitmap(typeof(GroupBoxEx))]
    public class GroupBoxEx : GroupBox
    {
        private Font _titleFont = new Font("宋体", 10, FontStyle.Regular);
        private Color _titleColor = Color.Green;
        private Color _borderColor = Color.FromArgb(23, 169, 254);
        private int _radius = 10;
        private int _tiltePos = 10;        private const int WM_ERASEBKGND = 0x0014;
        private const int WM_PAINT = 0xF;        public GroupBoxEx()
            : base()
        {
            //this.BackColor = System.Drawing.Color.Transparent;
        }        [DefaultValue(typeof(Color), "23, 169, 254"), Description("控件边框颜色")]
        public Color BorderColor
        {
            get { return _borderColor; }
            set
            {
                _borderColor = value;
                base.Invalidate();
            }
        }        [DefaultValue(typeof(Color), "Green"), Description("标题颜色")]
        public Color TitleColor
        {
            get { return _titleColor; }
            set
            {
                _titleColor = value;
                base.Invalidate();
            }
        }        [DefaultValue(typeof(Font), ""), Description("标题字体设置")]
        public Font TitleFont
        {
            get { return _titleFont; }
            set
            {
                _titleFont = value;
                base.Invalidate();
            }
        }
        [DefaultValue(typeof(int), "30"), Description("圆角弧度大小")]
        public int Radius
        {
            get { return _radius; }
            set
            {
                _radius = value;
                base.Invalidate();
            }
        }        [DefaultValue(typeof(int), "10"), Description("标题位置")]
        public int TiltePos
        {
            get { return _tiltePos; }
            set
            {
                _tiltePos = value;
                base.Invalidate();
            }
        }        protected override void WndProc(ref Message m)
        {
            try
            {
                base.WndProc(ref m);
                if (m.Msg == WM_PAINT)
                {
                    if (this.Radius > 0)
                    {
                        using (Graphics g = Graphics.FromHwnd(this.Handle))
                        {
                            Rectangle r = new Rectangle();
                            r.Width = this.Width;
                            r.Height = this.Height;
                            DrawBorder(g, r, this.Radius);
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }        private void DrawBorder(Graphics g, Rectangle rect, int radius)
        {
            rect.Width -= 1;
            rect.Height -= 1;
            using (Pen pen = new Pen(this.BorderColor))
            {
                g.Clear(this.BackColor);
                g.DrawString(this.Text, this.TitleFont, new SolidBrush(this.TitleColor), radius + this.TiltePos, 0);                g.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias;                GraphicsPath path = new GraphicsPath();                float height = g.MeasureString(this.Text, this.TitleFont).Height / 2;
                float width = g.MeasureString(this.Text, this.TitleFont).Width;                path.AddArc(rect.X, rect.Y + height, radius, radius, 180, 90);//左上角弧线
                path.AddLine(radius, rect.Y + height, radius + this.TiltePos, rect.Y + height);                path.StartFigure();                path.AddLine(radius + this.TiltePos + width, rect.Y + height, rect.Right - radius, rect.Y + height);                path.AddArc(rect.Right - radius, rect.Y + height, radius, radius, 270, 90);//右上角弧线
                path.AddArc(rect.Right - radius, rect.Bottom - radius, radius, radius, 0, 90);
                path.AddArc(rect.X, rect.Bottom - radius, radius, radius, 90, 90);                path.StartFigure();                path.AddArc(rect.X, rect.Y + height, radius, radius, -90, -90);//左上角弧线
                path.AddArc(rect.X, rect.Bottom - radius, radius, radius, -180, -90);
                g.DrawPath(pen, path);
            }
        }
    }
}

g.Clear(this.BackColor);
=>
g.Clear(this.BackColor == Color.Transparent ? Parent.BackColor : BackColor);

public class MyGroupBox : GroupBox
    {
        public MyGroupBox()
        {
            base.BackColor = Color.Transparent;        }        [Browsable(false)]
        public override Color BackColor
        {
            get
            {
                return base.BackColor;
            }
            set
            {
                base.BackColor = value;
            }
        }        private Color backColor = Color.Transparent;        public Color ActualBackColor
        {
            get { return this.backColor; }            set { this.backColor = value; }
        }        protected override void OnPaint(PaintEventArgs e)
        {            Size tSize = TextRenderer.MeasureText(this.Text, this.Font);            Rectangle borderRect = e.ClipRectangle;            borderRect.Y += tSize.Height / 2;            borderRect.Height -= tSize.Height / 2;            GraphicsPath gPath = CreatePath(0, borderRect.Y, (float)(this.Width - 1), borderRect.Height - 1, 5, true, true, true, true);            e.Graphics.FillPath(new SolidBrush(ActualBackColor), gPath);            e.Graphics.DrawPath(new Pen(Color.Red), gPath);            borderRect.X += 6;
            borderRect.Y -= 7;            e.Graphics.DrawString(this.Text, this.Font, new SolidBrush(this.ForeColor), borderRect);
        }        public GraphicsPath CreatePath(float x, float y, float width, float height,
                                      float radius, bool RoundTopLeft, bool RoundTopRight, bool RoundBottomRight, bool RoundBottomLeft)
        {
            float xw = x + width;
            float yh = y + height;
            float xwr = xw - radius;
            float yhr = yh - radius;
            float xr = x + radius;
            float yr = y + radius;
            float r2 = radius * 2;
            float xwr2 = xw - r2;
            float yhr2 = yh - r2;            GraphicsPath p = new GraphicsPath();
            p.StartFigure();            if (RoundTopLeft)
            {
                p.AddArc(x, y, r2, r2, 180, 90);
            }
            else
            {
                p.AddLine(x, yr, x, y);
                p.AddLine(x, y, xr, y);            }            p.AddLine(xr, y, xwr, y);            if (RoundTopRight)
            {
                p.AddArc(xwr2, y, r2, r2, 270, 90);
            }
            else
            {
                p.AddLine(xwr, y, xw, y);
                p.AddLine(xw, y, xw, yr);
            }            p.AddLine(xw, yr, xw, yhr);            if (RoundBottomRight)
            {
                p.AddArc(xwr2, yhr2, r2, r2, 0, 90);
            }
            else
            {
                p.AddLine(xw, yhr, xw, yh);
                p.AddLine(xw, yh, xwr, yh);
            }            p.AddLine(xwr, yh, xr, yh);                   if (RoundBottomLeft)
            {
                p.AddArc(x, yhr2, r2, r2, 90, 90);
            }
            else
            {
                p.AddLine(xr, yh, x, yh);
                p.AddLine(x, yh, x, yhr);
            }            p.AddLine(x, yhr, x, yr);            p.CloseFigure();
            return p;
        }
    }
Form1中放一个Panel，设置一张背景图片，然后在Page_Load中调用
MyGroupBox a = new MyGroupBox();
a.Text = "我是文本";
a.ForeColor = Color.White;
a.Location = new Point(10, 10);
panel1.Controls.Add(a);
可以看见边框是红色，背景是透明的，即Panel的背景图片主要就是Override OnPaint事件，而不是写他的Paint事件，没什么东西，你自己再将园边框和文字位置处理一下

10楼的可以实现
不过
groupBox.text 文字下面有红色的线

感谢你 wknight_IT
关键不是技术不太行吗？
能给个完整的就好了！

调试易

一个问题搞了一个星期了，大家给看下

解决方案 »

一个问题搞了 一个星期了，大家给看下

解决方案 »

一个问题搞了一个星期了，大家给看下