/// <summary>
/// 绘制选择区域的背景色
/// </summary>
/// <param name="draw">用来绘制图像的设备</param>
/// <param name="content">内容</param>
/// <param name="color">背景颜色</param>
private void DrawBackground(IDraw draw,EditorContent content,int color)
{
draw.FillRectangle(
color,
content.Rectangle.Left,
content.Rectangle.Top,
content.Rectangle.Width,
content.Rectangle.Height,
null);
}