Question

帮解释下面delphi代码，特别是那个Update。刚开始转delphi

oCopyProgressObj := TCopyProgressForm.Create(Application);
oCopyProgressObj.Show;
oCopyProgressObj.Update;

Answer 1

第一句创建一个TCopyProgressForm的窗口对象，应该是一个用来显示文件复制进度的窗口。
第二句Show显示这个窗口。
第三句Update相当于调用了Windows API UpdateWindow, 作用是跳过消息队列，直接给窗口处理函数发送一个WM_PAINT消息，结果是让窗口重新绘制（刷新）自己。

Answer 2

oCopyProgressObj := TCopyProgressForm.Create(Application);创建Form对象
oCopyProgressObj.Show; 这个是显示
oCopyProgressObj.Update;这个就要看TCopyProgressForm这个了
TCopyProgressForm是自定义的控件吧？不是delphi本身有的吧？我的delphi7没有这个控件
如果是wincontrol的update是这样描述的：
Description

Update repaints any part of the control surface that is out of date. Normally, updates occur automatically, but an Update call may be necessary before lengthy processing that might interfere with automatic updates. Calling Update unnecessarily can increase overhead and cause screen flicker.
Update only repaints areas of the control the have been determined to be out of date. To force immediate repainting of the entire control, call the Repaint method. To notify a control that it is out of date (without forcing an immediate repaint), call the Invalidate method.

Form5.Update; // force display of Form5

Answer 3

oCopyProgressObj := TCopyProgressForm.Create(Application); //创建窗体
oCopyProgressObj.Show; //窗体显示
oCopyProgressObj.Update; //窗体更新