在C#，GDI+中，怎样把画出来的矩形（Rectangle）的四个角变成圆形，使其变成一个圆角矩形。

Answer 1

public static void FillRoundRectangle(Graphics g, Brush brush, Rectangle rect, int cornerRadius)
{
using (GraphicsPath path = CreateRoundedRectanglePath(rect, cornerRadius))
{
g.FillPath(brush, path);
}
}

internal static GraphicsPath CreateRoundedRectanglePath(Rectangle rect, int cornerRadius)
{
GraphicsPath roundedRect = new GraphicsPath();
roundedRect.AddArc(rect.X, rect.Y, cornerRadius * 2, cornerRadius * 2, 180, 90);
roundedRect.AddLine(rect.X + cornerRadius, rect.Y, rect.Right - cornerRadius * 2, rect.Y);
roundedRect.AddArc(rect.X + rect.Width - cornerRadius * 2, rect.Y, cornerRadius * 2, cornerRadius * 2, 270, 90);
roundedRect.AddLine(rect.Right, rect.Y + cornerRadius * 2, rect.Right, rect.Y + rect.Height - cornerRadius * 2);
roundedRect.AddArc(rect.X + rect.Width - cornerRadius * 2, rect.Y + rect.Height - cornerRadius * 2, cornerRadius * 2, cornerRadius * 2, 0, 90);
roundedRect.AddLine(rect.Right - cornerRadius * 2, rect.Bottom, rect.X + cornerRadius * 2, rect.Bottom);
roundedRect.AddArc(rect.X, rect.Bottom - cornerRadius * 2, cornerRadius * 2, cornerRadius * 2, 90, 90);
roundedRect.AddLine(rect.X, rect.Bottom - cornerRadius * 2, rect.X, rect.Y + cornerRadius * 2);
roundedRect.CloseFigure();
return roundedRect;
}

Answer 2

shift+好像，有点忘了