【C#】分享一个可灵活设置边框的Panel

---------------------------更新：2014-05-19---------------------------

优化了一下逻辑，就是既然可以通过设置BorderSide=None来不显示边框，那么再设计一个BorderMode.None就显得多余，即BorderMode枚举只需要2个元素即可（Single和ThreeD），而与其弄一个只有2个元素的枚举还不如干脆不要这个枚举，改为给PanelEx加一个布尔属性BorderIsSingleMode（之所以这样命名是考虑把与边框相关的属性都以Border开头，方便在设计器中使用），为true则代表单色模式，否则为三维模式，而显不显示、显示哪些边则完全交给BorderSide控制，同时把BorderSide的默认值设为None，即默认不显示边框。修改后的代码如下：

using System; using System.ComponentModel; using System.Drawing; using System.Windows.Forms; namespace AhDung.Controls { /// <summary>
    /// 可设置边框样式的Panel /// </summary>
    public class PanelEx : Panel { private Color borderColor; private Border3DStyle border3DStyle; private ToolStripStatusLabelBorderSides borderSide; private bool borderIsSingleMode; [DefaultValue(true), Description("指定边框是否为单色模式。false代表三维模式")] public bool BorderIsSingleMode { get { return borderIsSingleMode; } set { if (borderIsSingleMode == value) { return; } borderIsSingleMode = value; this.Invalidate(); } } [DefaultValue(typeof(Color), "Black"), Description("边框颜色。仅当边框为单色模式时有效")] public Color BorderColor { get { return borderColor; } set { if (borderColor == value) { return; } borderColor = value; this.Invalidate(); } } [DefaultValue(Border3DStyle.Etched), Description("边框三维样式。仅当边框为三维模式时有效")] public Border3DStyle Border3DStyle { get { return border3DStyle; } set { if (border3DStyle == value) { return; } border3DStyle = value; this.Invalidate(); } } //之所以不直接用Border3DSide是因为这货不被设计器支持，没法灵活选择位置组合
        [DefaultValue(ToolStripStatusLabelBorderSides.None), Description("边框位置。可自由启用各个方位的边框")] public ToolStripStatusLabelBorderSides BorderSide { get { return borderSide; } set { if (borderSide == value) { return; } borderSide = value; this.Invalidate(); } } public PanelEx() { this.borderIsSingleMode = true; this.borderColor = Color.Black; this.border3DStyle = System.Windows.Forms.Border3DStyle.Etched; this.borderSide = ToolStripStatusLabelBorderSides.None; } protected override void OnPaint(PaintEventArgs e) { base.OnPaint(e); if (this.BorderStyle != System.Windows.Forms.BorderStyle.None || BorderSide == ToolStripStatusLabelBorderSides.None) { return; } using (Graphics g = e.Graphics) { //单色模式
                if (this.BorderIsSingleMode) { using (Pen pen = new Pen(BorderColor)) { //若是四条边都启用，则直接画矩形
                        if (BorderSide == ToolStripStatusLabelBorderSides.All) { g.DrawRectangle(pen, 0, 0, this.Width - 1, this.Height - 1); } else //否则分别绘制线条
 { if ((BorderSide & ToolStripStatusLabelBorderSides.Top) == ToolStripStatusLabelBorderSides.Top) { g.DrawLine(pen, 0, 0, this.Width - 1, 0); } if ((BorderSide & ToolStripStatusLabelBorderSides.Right) == ToolStripStatusLabelBorderSides.Right) { g.DrawLine(pen, this.Width - 1, 0, this.Width - 1, this.Height - 1); } if ((BorderSide & ToolStripStatusLabelBorderSides.Bottom) == ToolStripStatusLabelBorderSides.Bottom) { g.DrawLine(pen, 0, this.Height - 1, this.Width - 1, this.Height - 1); } if ((BorderSide & ToolStripStatusLabelBorderSides.Left) == ToolStripStatusLabelBorderSides.Left) { g.DrawLine(pen, 0, 0, 0, this.Height - 1); } } } } else //三维模式
 { ControlPaint.DrawBorder3D(g, this.ClientRectangle, this.Border3DStyle, (Border3DSide) BorderSide); //这儿要将ToolStripStatusLabelBorderSides转换为Border3DSide
 } } } } }

---------------------------原文：2014-05-14---------------------------

注：此乃Winform控件，开发环境为.net 2.0

工作需要，我对自带Panel进行了一下呈现上的扩展，方便设置边框效果。先看效果：

说明：

* 只有当原有属性BorderStyle为None时才能应用样式，此时可通过BorderMode设置【不显示、单色、三维】三种边框模式；这是因为BorderStyle为FixedSingle或Fixed3D时，自带边框似乎不属于Panel的一部分，不能控制或清除，我猜应该是底层API负责绘制的，所以唯有在None时才能自由发挥；

* 无论单色或是三维模式，均可通过BorderSide自由启用/禁用各个方位的边框；

* 在单色模式下，可通过BorderColor设置边框颜色，此时设置三维样式（Border3DStyle）无效；

* 在三维模式下，可通过Border3DStyle设置三维样式，此时设置边框颜色（BorderColor）无效；

代码在此：

using System; using System.ComponentModel; using System.Drawing; using System.Windows.Forms; namespace AhDung.Controls { /// <summary>
    /// 边框模式（无、单色、三维） /// </summary>
    public enum BorderMode { None, Single, ThreeD } /// <summary>
    /// 可设置边框样式的Panel /// </summary>
    public class PanelEx : Panel { private Color borderColor; private Border3DStyle border3DStyle; private ToolStripStatusLabelBorderSides borderSide; private BorderMode borderMode; [DefaultValue(BorderMode.None), Description("边框模式。可设置单色模式或三维模式")] public BorderMode BorderMode { get { return borderMode; } set { if (borderMode == value) { return; } borderMode = value; this.Invalidate(); } } [DefaultValue(typeof(Color), "Black"), Description("边框颜色。仅当边框为单色模式时有效")] public Color BorderColor { get { return borderColor; } set { if (borderColor == value) { return; } borderColor = value; this.Invalidate(); } } [DefaultValue(Border3DStyle.Etched), Description("边框三维样式。仅当边框为三维模式时有效")] public Border3DStyle Border3DStyle { get { return border3DStyle; } set { if (border3DStyle == value) { return; } border3DStyle = value; this.Invalidate(); } } //之所以不直接用Border3DSide是因为这货不被设计器支持，没法灵活选择位置组合
        [DefaultValue(ToolStripStatusLabelBorderSides.All), Description("边框位置。可自由启用各个方位的边框")] public ToolStripStatusLabelBorderSides BorderSide { get { return borderSide; } set { if (borderSide == value) { return; } borderSide = value; this.Invalidate(); } } public PanelEx() { this.borderMode = BorderMode.None; this.borderColor = Color.Black; this.border3DStyle = System.Windows.Forms.Border3DStyle.Etched; this.borderSide = ToolStripStatusLabelBorderSides.All; } protected override void OnPaint(PaintEventArgs e) { base.OnPaint(e); if (this.BorderStyle != System.Windows.Forms.BorderStyle.None || BorderMode == BorderMode.None || BorderSide == ToolStripStatusLabelBorderSides.None) { return; } using (Graphics g = e.Graphics) { //三维模式
                if (this.BorderMode == BorderMode.ThreeD) { ControlPaint.DrawBorder3D(g, this.ClientRectangle, this.Border3DStyle, (Border3DSide)BorderSide);//这儿要将ToolStripStatusLabelBorderSides转换为Border3DSide
 } else //单色模式
 { using (Pen pen = new Pen(BorderColor)) { //若是四条边都启用，则直接画矩形
                        if (BorderSide == ToolStripStatusLabelBorderSides.All) { g.DrawRectangle(pen, 0, 0, this.Width - 1, this.Height - 1); } else //否则分别绘制线条
 { if ((BorderSide & ToolStripStatusLabelBorderSides.Top) == ToolStripStatusLabelBorderSides.Top) { g.DrawLine(pen, 0, 0, this.Width - 1, 0); } if ((BorderSide & ToolStripStatusLabelBorderSides.Right) == ToolStripStatusLabelBorderSides.Right) { g.DrawLine(pen, this.Width - 1, 0, this.Width - 1, this.Height - 1); } if ((BorderSide & ToolStripStatusLabelBorderSides.Bottom) == ToolStripStatusLabelBorderSides.Bottom) { g.DrawLine(pen, 0, this.Height - 1, this.Width - 1, this.Height - 1); } if ((BorderSide & ToolStripStatusLabelBorderSides.Left) == ToolStripStatusLabelBorderSides.Left) { g.DrawLine(pen, 0, 0, 0, this.Height - 1); } } } } } } } }

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