概述(Overview)
参考了网上的分享，感觉都不太理想：1.一个控件内如果包含多个子控件时没有考虑顺序问题；2.超出控件可显示区域时不能长截图，有滚动条会多余截取了滚动条。这个随笔旨在解决这个问题，实现带滚动条时可以长截图，并且给出了在多个子控件的情况下如何控制截图顺序的代码。有用可以点个赞。引用本文章请注明出处，谢谢。
(Referring to the Share on the Internet, I feel that it is not ideal: 1. If there are multiple sub-controls in a control, the order is not considered; 2. When the display area of the control is exceeded, the screenshot cannot be long, and the scroll bar will be redundantly intercepted. This essay aims to solve this problem by implementing long screenshots with scrollbars, and gives code on how to control the order of screenshots in the case of multiple child controls. If it's useful, you can like it. Please indicate the source for citing this article, thank you.)
1 /// <summary>
2 /// 绘制整个控件以及子控件
3 /// </summary>
4 /// <param name="ctrl">窗口/控件</param>
5 /// <param name="bitmap">bit图片</param>
6 /// <returns></returns>
7 private Bitmap DrawToBitmap(Control ctrl, Bitmap bitmap = null)
8 {
9 //获取整个界面的大小
10 var w = ctrl.DisplayRectangle.Width;
11 var h = ctrl.DisplayRectangle.Height;
12
13 //长截图
14 if (bitmap == null)
15 {
16 bitmap = ctrl.BackgroundImage == null ? new Bitmap(w, h) : new Bitmap(ctrl.BackgroundImage);
17 }
18
19 if (ctrl.HasChildren)
20 {
21 //绘制子控件内容（逆序处理：图层从下开始往上叠取）
22 for (int i = ctrl.Controls.Count - 1; i >= 0; i--)
23 {
24 var control = ctrl.Controls[i];
25 //重新计算图片在bitmap上的位置
26 var newLocation = new Point(control.Location.X - ctrl.DisplayRectangle.X, control.Location.Y - ctrl.DisplayRectangle.Y);
27
28 using (Bitmap temp = new Bitmap(control.Width, control.Height))
29 using (Graphics g = Graphics.FromImage(bitmap))
30 {
31 control.DrawToBitmap(temp, new Rectangle(new Point(0, 0), control.Size));
32 g.DrawImage(temp, new Rectangle(newLocation, control.Size));
33 }
34 DrawToBitmap(control, bitmap);
35 }
36 }
37
38 return bitmap;
39 }Code