c# - 如何更改组框边框的颜色？

Question

在 C#.NET 中，我试图以编程方式更改组框中边框的颜色。

更新：在我们切换到 .NET 之前，当我在 winforms 系统上工作时，有人问过这个问题。

Answer 1

只需添加绘画事件。

    private void groupBox1_Paint(object sender, PaintEventArgs e)
    {
        GroupBox box = sender as GroupBox;
        DrawGroupBox(box, e.Graphics, Color.Red, Color.Blue);
    }


    private void DrawGroupBox(GroupBox box, Graphics g, Color textColor, Color borderColor)
    {
        if (box != null)
        {
            Brush textBrush = new SolidBrush(textColor);
            Brush borderBrush = new SolidBrush(borderColor);
            Pen borderPen = new Pen(borderBrush);
            SizeF strSize = g.MeasureString(box.Text, box.Font);
            Rectangle rect = new Rectangle(box.ClientRectangle.X,
                                           box.ClientRectangle.Y + (int)(strSize.Height / 2),
                                           box.ClientRectangle.Width - 1,
                                           box.ClientRectangle.Height - (int)(strSize.Height / 2) - 1);

            // Clear text and border
            g.Clear(this.BackColor);

            // Draw text
            g.DrawString(box.Text, box.Font, textBrush, box.Padding.Left, 0);

            // Drawing Border
            //Left
            g.DrawLine(borderPen, rect.Location, new Point(rect.X, rect.Y + rect.Height));
            //Right
            g.DrawLine(borderPen, new Point(rect.X + rect.Width, rect.Y), new Point(rect.X + rect.Width, rect.Y + rect.Height));
            //Bottom
            g.DrawLine(borderPen, new Point(rect.X, rect.Y + rect.Height), new Point(rect.X + rect.Width, rect.Y + rect.Height));
            //Top1
            g.DrawLine(borderPen, new Point(rect.X, rect.Y), new Point(rect.X + box.Padding.Left, rect.Y));
            //Top2
            g.DrawLine(borderPen, new Point(rect.X + box.Padding.Left + (int)(strSize.Width), rect.Y), new Point(rect.X + rect.Width, rect.Y));
        }
    }

Answer 2

基于上一个答案，一个更好的解决方案，包括组框的标签：

groupBox1.Paint += PaintBorderlessGroupBox;

private void PaintBorderlessGroupBox(object sender, PaintEventArgs p)
{
  GroupBox box = (GroupBox)sender;
  p.Graphics.Clear(SystemColors.Control);
  p.Graphics.DrawString(box.Text, box.Font, Brushes.Black, 0, 0);
}

您可能想调整文本的 x/y，但对于我的使用来说，这是正确的。

Answer 3

只需将任何对象（不仅仅是按钮）上的绘制动作设置为此方法即可绘制边框。

    private void UserControl1_Paint(object sender, PaintEventArgs e)
    {
        ControlPaint.DrawBorder(e.Graphics, this.ClientRectangle, Color.Red, ButtonBorderStyle.Solid);

    }

它仍然不会像原来的那样漂亮和圆润，但它要简单得多。

Answer 4

FWIW，这是我使用的实现。它是 GroupBox 的子对象，但不仅可以设置 BorderColor，还可以设置边框的粗细和圆角的半径。此外，您可以为 GroupBox 标签设置所需的缩进量，并使用右侧的负缩进缩进。

using System;
using System.Drawing;
using System.Windows.Forms;

namespace BorderedGroupBox
{
    public class BorderedGroupBox : GroupBox
    {
        private Color _borderColor = Color.Black;
        private int _borderWidth = 2;
        private int _borderRadius = 5;
        private int _textIndent = 10;

        public BorderedGroupBox() : base()
        {
            InitializeComponent();
            this.Paint += this.BorderedGroupBox_Paint;
        }

        public BorderedGroupBox(int width, float radius, Color color) : base()
        {
            this._borderWidth = Math.Max(1,width);
            this._borderColor = color;
            this._borderRadius = Math.Max(0,radius);
            InitializeComponent();
            this.Paint += this.BorderedGroupBox_Paint;
        }

        public Color BorderColor
        {
            get => this._borderColor;
            set
            {
                this._borderColor = value;
                DrawGroupBox();
            }
        }

        public int BorderWidth
        {
            get => this._borderWidth;
            set
            {
                if (value > 0)
                {
                    this._borderWidth = Math.Min(value, 10);
                    DrawGroupBox();
                }
            }
        }

        public int BorderRadius
        {
            get => this._borderRadius;
            set
            {   // Setting a radius of 0 produces square corners...
                if (value >= 0)
                {
                    this._borderRadius = value;
                    this.DrawGroupBox();
                }
            }
        }

        public int LabelIndent
        {
            get => this._textIndent;
            set
            {
                this._textIndent = value;
                this.DrawGroupBox();
            }
        }

        private void BorderedGroupBox_Paint(object sender, PaintEventArgs e) =>
            DrawGroupBox(e.Graphics);

        private void DrawGroupBox() =>
            this.DrawGroupBox(this.CreateGraphics());

        private void DrawGroupBox(Graphics g)
        {
            Brush textBrush = new SolidBrush(this.ForeColor);
            SizeF strSize = g.MeasureString(this.Text, this.Font);

            Brush borderBrush = new SolidBrush(this.BorderColor);
            Pen borderPen = new Pen(borderBrush,(float)this._borderWidth);
            Rectangle rect = new Rectangle(this.ClientRectangle.X,
                                            this.ClientRectangle.Y + (int)(strSize.Height / 2),
                                            this.ClientRectangle.Width - 1,
                                            this.ClientRectangle.Height - (int)(strSize.Height / 2) - 1);

            Brush labelBrush = new SolidBrush(this.BackColor);

            // Clear text and border
            g.Clear(this.BackColor);

            // Drawing Border (added "Fix" from Jim Fell, Oct 6, '18)
            int rectX = (0 == this._borderWidth % 2) ? rect.X + this._borderWidth / 2 : rect.X + 1 + this._borderWidth / 2;
            int rectHeight = (0 == this._borderWidth % 2) ? rect.Height - this._borderWidth / 2 : rect.Height - 1 - this._borderWidth / 2;
            // NOTE DIFFERENCE: rectX vs rect.X and rectHeight vs rect.Height
            g.DrawRoundedRectangle(borderPen, rectX, rect.Y, rect.Width, rectHeight, (float)this._borderRadius);

            // Draw text
            if (this.Text.Length > 0)
            {
                // Do some work to ensure we don't put the label outside
                // of the box, regardless of what value is assigned to the Indent:
                int width = (int)rect.Width, posX;
                posX = (this._textIndent < 0) ? Math.Max(0-width,this._textIndent) : Math.Min(width, this._textIndent);
                posX = (posX < 0) ? rect.Width + posX - (int)strSize.Width : posX;
                g.FillRectangle(labelBrush, posX, 0, strSize.Width, strSize.Height);
                g.DrawString(this.Text, this.Font, textBrush, posX, 0);
            }
        }

        #region Component Designer generated code
        /// <summary>Required designer variable.</summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>Clean up any resources being used.</summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
                components.Dispose();

            base.Dispose(disposing);
        }

        /// <summary>Required method for Designer support - Don't modify!</summary>
        private void InitializeComponent() => components = new System.ComponentModel.Container();
        #endregion
    }
}

要使其工作，您还必须扩展基本 Graphics 类（注意：这是从我在尝试创建圆角面板控件时发现的一些代码派生的，但我找不到原始帖子在此处链接）：

static class GraphicsExtension
{
    private static GraphicsPath GenerateRoundedRectangle(
        this Graphics graphics,
        RectangleF rectangle,
        float radius)
    {
        float diameter;
        GraphicsPath path = new GraphicsPath();
        if (radius <= 0.0F)
        {
            path.AddRectangle(rectangle);
            path.CloseFigure();
            return path;
        }
        else
        {
            if (radius >= (Math.Min(rectangle.Width, rectangle.Height)) / 2.0)
                return graphics.GenerateCapsule(rectangle);
            diameter = radius * 2.0F;
            SizeF sizeF = new SizeF(diameter, diameter);
            RectangleF arc = new RectangleF(rectangle.Location, sizeF);
            path.AddArc(arc, 180, 90);
            arc.X = rectangle.Right - diameter;
            path.AddArc(arc, 270, 90);
            arc.Y = rectangle.Bottom - diameter;
            path.AddArc(arc, 0, 90);
            arc.X = rectangle.Left;
            path.AddArc(arc, 90, 90);
            path.CloseFigure();
        }
        return path;
    }

    private static GraphicsPath GenerateCapsule(
        this Graphics graphics,
        RectangleF baseRect)
    {
        float diameter;
        RectangleF arc;
        GraphicsPath path = new GraphicsPath();
        try
        {
            if (baseRect.Width > baseRect.Height)
            {
                diameter = baseRect.Height;
                SizeF sizeF = new SizeF(diameter, diameter);
                arc = new RectangleF(baseRect.Location, sizeF);
                path.AddArc(arc, 90, 180);
                arc.X = baseRect.Right - diameter;
                path.AddArc(arc, 270, 180);
            }
            else if (baseRect.Width < baseRect.Height)
            {
                diameter = baseRect.Width;
                SizeF sizeF = new SizeF(diameter, diameter);
                arc = new RectangleF(baseRect.Location, sizeF);
                path.AddArc(arc, 180, 180);
                arc.Y = baseRect.Bottom - diameter;
                path.AddArc(arc, 0, 180);
            }
            else path.AddEllipse(baseRect);
        }
        catch { path.AddEllipse(baseRect); }
        finally { path.CloseFigure(); }
        return path;
    }

    /// <summary>
    /// Draws a rounded rectangle specified by a pair of coordinates, a width, a height and the radius
    /// for the arcs that make the rounded edges.
    /// </summary>
    /// <param name="brush">System.Drawing.Pen that determines the color, width and style of the rectangle.</param>
    /// <param name="x">The x-coordinate of the upper-left corner of the rectangle to draw.</param>
    /// <param name="y">The y-coordinate of the upper-left corner of the rectangle to draw.</param>
    /// <param name="width">Width of the rectangle to draw.</param>
    /// <param name="height">Height of the rectangle to draw.</param>
    /// <param name="radius">The radius of the arc used for the rounded edges.</param>
    public static void DrawRoundedRectangle(
        this Graphics graphics,
        Pen pen,
        float x,
        float y,
        float width,
        float height,
        float radius)
    {
        RectangleF rectangle = new RectangleF(x, y, width, height);
        GraphicsPath path = graphics.GenerateRoundedRectangle(rectangle, radius);
        SmoothingMode old = graphics.SmoothingMode;
        graphics.SmoothingMode = SmoothingMode.AntiAlias;
        graphics.DrawPath(pen, path);
        graphics.SmoothingMode = old;
    }

    /// <summary>
    /// Draws a rounded rectangle specified by a pair of coordinates, a width, a height and the radius
    /// for the arcs that make the rounded edges.
    /// </summary>
    /// <param name="brush">System.Drawing.Pen that determines the color, width and style of the rectangle.</param>
    /// <param name="x">The x-coordinate of the upper-left corner of the rectangle to draw.</param>
    /// <param name="y">The y-coordinate of the upper-left corner of the rectangle to draw.</param>
    /// <param name="width">Width of the rectangle to draw.</param>
    /// <param name="height">Height of the rectangle to draw.</param>
    /// <param name="radius">The radius of the arc used for the rounded edges.</param>

    public static void DrawRoundedRectangle(
        this Graphics graphics,
        Pen pen,
        int x,
        int y,
        int width,
        int height,
        int radius)
    {
        graphics.DrawRoundedRectangle(
            pen,
            Convert.ToSingle(x),
            Convert.ToSingle(y),
            Convert.ToSingle(width),
            Convert.ToSingle(height),
            Convert.ToSingle(radius));
    }
}

Answer 5

我不确定这是否适用于所有情况，但多亏了这个线程，我们使用以下方式快速以编程方式连接到 Paint 事件：

GroupBox box = new GroupBox();
[...]
box.Paint += delegate(object o, PaintEventArgs p)
{
    p.Graphics.Clear(someColorHere);
};

干杯!

Answer 6

我已经实现了与新手可能更容易理解的东西相同的边界：

    private void groupSchitaCentru_Paint(object sender, PaintEventArgs e)
    {
        Pen blackPen = new Pen(Color.Black, 2);
        Point pointTopLeft = new Point(0, 7);
        Point pointBottomLeft = new Point(0, groupSchitaCentru.ClientRectangle.Height);
        Point pointTopRight = new Point(groupSchitaCentru.ClientRectangle.Width, 7);
        Point pointBottomRight = new Point(groupSchitaCentru.ClientRectangle.Width, groupSchitaCentru.ClientRectangle.Height);

        e.Graphics.DrawLine(blackPen, pointTopLeft, pointBottomLeft);
        e.Graphics.DrawLine(blackPen, pointTopLeft, pointTopRight);
        e.Graphics.DrawLine(blackPen, pointBottomRight, pointTopRight);
        e.Graphics.DrawLine(blackPen, pointBottomLeft, pointBottomRight);
    }

1. 在 GroupBox 控件上设置 Paint 事件。在此示例中，我的控件的名称是“groupSchitaCentru”。因为它的参数 e 需要这个事件。
2. 通过使用 System.Drawing.Pen 类设置笔对象：https ://msdn.microsoft.com/en-us/library/f956fzw1(v=vs.110).aspx
3. 设置表示控件表示的矩形的角的点。使用控件的属性 ClientRectangle 来获取其尺寸。我使用 TopLeft (0,7) 因为我想尊重控件的边框，并围绕其文本画线。要获取有关坐标系统的更多信息，请访问此处：https ://docs.microsoft.com/en-us/dotnet/framework/winforms/windows-forms-coordinates

我不知道，这可能有助于寻求实现这种边界调整的人。

Answer 7

对 Jim Fell 的代码进行的这个调整让我的边框更好一些，但是添加为注释太长了

...

   Rectangle rect = new Rectangle(this.ClientRectangle.X,
                                        this.ClientRectangle.Y + (int)(strSize.Height / 2),
                                        this.ClientRectangle.Width,
                                        this.ClientRectangle.Height - (int)(strSize.Height / 2));

    Brush labelBrush = new SolidBrush(this.BackColor);

    // Clear text and border
    g.Clear(this.BackColor);


    int drawX = rect.X;
    int drawY = rect.Y;
    int drawWidth = rect.Width;
    int drawHeight = rect.Height;

    if (this._borderWidth > 0)
    {
        drawX += this._borderWidth / 2;
        drawY += this._borderWidth / 2;

        drawWidth -= this._borderWidth;
        drawHeight -= this._borderWidth;
        
        if (this._borderWidth % 2 == 0)
        {
            drawX -= 1;
            drawWidth += 1;

            drawY -= 1;
            drawHeight += 1;
        }
    }

    g.DrawRoundedRectangle(borderPen, drawX, drawY, drawWidth, drawHeight, (float)this._borderRadius);