private Color _borderColor = Color.FromArgb(23, 169, 254);
private int _radius = 10;
private RoundStyle _roundeStyle;
private const int WM_PAINT = 0xF;
/// <summary>
/// 建立圆角路径的样式。
/// </summary>
public enum RoundStyle
{
/// <summary>
/// 四个角都不是圆角。
/// </summary>
None = 0,
/// <summary>
/// 四个角都为圆角。
/// </summary>
All = 1,
/// <summary>
/// 左边两个角为圆角。
/// </summary>
Left = 2,
/// <summary>
/// 右边两个角为圆角。
/// </summary>
Right = 3,
/// <summary>
/// 上边两个角为圆角。
/// </summary>
Top = 4,
/// <summary>
/// 下边两个角为圆角。
/// </summary>
Bottom = 5,
}
/// <summary>
/// 建立带有圆角样式的路径。
/// </summary>
/// <param name="rect">用来建立路径的矩形。</param>
/// <param name="_radius">圆角的大小。</param>
/// <param name="style">圆角的样式。</param>
/// <param name="correction">是否把矩形长宽减 1,以便画出边框。</param>
/// <returns>建立的路径。</returns>
GraphicsPath CreatePath(Rectangle rect, int radius, RoundStyle style, bool correction)
{
GraphicsPath path = new GraphicsPath();
int radiusCorrection = correction ? 1 : 0;
switch (style)
{
case RoundStyle.None:
path.AddRectangle(rect);
break;
case RoundStyle.All:
path.AddArc(rect.X, rect.Y, radius, radius, 180, 90);
path.AddArc(rect.Right - radius - radiusCorrection, rect.Y, radius, radius, 270, 90);
path.AddArc(rect.Right - radius - radiusCorrection, rect.Bottom - radius - radiusCorrection, radius, radius, 0, 90);
path.AddArc(rect.X, rect.Bottom - radius - radiusCorrection, radius, radius, 90, 90);
break;
case RoundStyle.Left:
path.AddArc(rect.X, rect.Y, radius, radius, 180, 90);
path.AddLine(rect.Right - radiusCorrection, rect.Y, rect.Right - radiusCorrection, rect.Bottom - radiusCorrection);
path.AddArc(rect.X, rect.Bottom - radius - radiusCorrection, radius, radius, 90, 90);
break;
case RoundStyle.Right:
path.AddArc(rect.Right - radius - radiusCorrection, rect.Y, radius, radius, 270, 90);
path.AddArc(rect.Right - radius - radiusCorrection, rect.Bottom - radius - radiusCorrection, radius, radius, 0, 90);
path.AddLine(rect.X, rect.Bottom - radiusCorrection, rect.X, rect.Y);
break;
case RoundStyle.Top:
path.AddArc(rect.X, rect.Y, radius, radius, 180, 90);
path.AddArc(rect.Right - radius - radiusCorrection, rect.Y, radius, radius, 270, 90);
path.AddLine(rect.Right - radiusCorrection, rect.Bottom - radiusCorrection, rect.X, rect.Bottom - radiusCorrection);
break;
case RoundStyle.Bottom:
path.AddArc(rect.Right - radius - radiusCorrection, rect.Bottom - radius - radiusCorrection, radius, radius, 0, 90);
path.AddArc(rect.X, rect.Bottom - radius - radiusCorrection, radius, radius, 90, 90);
path.AddLine(rect.X, rect.Y, rect.Right - radiusCorrection, rect.Y);
break;
}
path.CloseFigure(); //这句很关键,缺少会没有左边线。
return path;
}
[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(int), "10"), Description("圆角弧度大小")]
public int Radius
{
get { return _radius; }
set
{
_radius = value;
base.Invalidate();
}
}
public RoundStyle RoundeStyle
{
get { return _roundeStyle; }
set
{
_roundeStyle = 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.RoundeStyle, this.Radius);
}
}
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
private void DrawBorder(Graphics g, Rectangle rect, RoundStyle roundStyle, int radius)
{
rect.Width -= 1;
rect.Height -= 1;
using (GraphicsPath path = CreatePath(rect, radius, roundStyle, false))
{
using (Pen pen = new Pen(this.BorderColor))
{
g.DrawPath(pen, path);
}
}
}