控制PointToClient（）与PointToScreen（） [英] Control PointToClient() vs PointToScreen()

问题描述

恕我直言，MSDN没有提供 Control.PointToScreen （链接）和 Control.PointToClient （链接）方法。

The MSDN does not provide, IMHO, a clear difference between Control.PointToScreen(link) and Control.PointToClient(link) methods.

有人可以用几个简单的词解释这些方法之间的区别。

Is there somebody who could explain in a few simple words what is the difference between these methods. Especially is unclear for me the notion of "Client".

我了解PointToScreen的真实屏幕坐标（在屏幕的左上角带有[0，0]），对我来说尤其不清楚。

I understand PointToScreen the real screen coordinate (with [0, 0] in the left upper corner of the screen) of the given point.

例如，调试一些我拥有的代码

By example, debugging some code I have

?click.Location 
{X = 3 Y = 9}

?shapeSender.PointToClient(click.Location)
{X = -470 Y = -565}

?shapeSender.PointToScreen(click.Location)
{X = 476 Y = 583}

谢谢。

推荐答案

最好的解决方法是：相对坐标和绝对坐标。相对坐标是从窗口客户区的左上角开始的相对坐标。窗口的工作区是一个减去边界的窗口。相对坐标很有用，因为用户移动窗口时它们不会改变，并且不依赖于窗口的边框和标题大小。

Best way to think of it is: relative vs absolution coordinates. Where the relative coordinate is relative from the upper left corner of the client area of a window. The client area of a window is a window minus its border. Relative coordinates are useful because they don't change when the user moves a window and don't depend on the border and caption size of the window.

Winforms中的大多数坐标是相对坐标，例如MouseEventArgs.Location。有些是绝对的，例如Cursor.Position。如果您将一个相对坐标传递给PointToClient，则会出现垃圾，就像在调试会话中看到的那样。它必须是绝对坐标。

Most coordinates in Winforms are relative coordinates, MouseEventArgs.Location for example. Some are absolute, Cursor.Position for example. If you pass a relative coordinate to PointToClient you'll get garbage, as you saw in your debug session. It must be an absolute coordinate.

某些坐标属性似乎可以兼具，例如Control.Location。在子控件上，它表示控件相对于其容器的位置。表单的位置是绝对的。当您将Control.Location视为来自控件的父级的亲戚时，这种看似矛盾就消失了。窗体的父级是桌面。

Some coordinate properties can seemingly be both, Control.Location for example. On a child control it represents the control's location relative from its container. A form's Location is absolute. That seeming contradiction disappears when you think a Control.Location as relative from a control's Parent. The Parent of a form is the desktop.

常见用法是将相对于一个控件的坐标映射到另一个控件。首先使用 control1.PointToScreen（）映射到绝对屏幕坐标，然后使用 control2.PointToClient（）。无论控件的父母是谁，Point值都将根据控件之间的偏移量而变化。

A common usage is to map a coordinate relative to one control to another control. First map to absolute screen coordinates with control1.PointToScreen(), then map the result to the other control with control2.PointToClient(). The Point value changes by the offset between the controls, regardless of who their parents are. Doing it any other way is very painful.

仅通过将绝对坐标传递给PointToClient并将相对坐标传递给PointToScreen来避免麻烦。

Keep out of trouble by only ever passing an absolute coordinate to PointToClient and a relative coordinate to PointToScreen.

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