Question

在Delphi Prism,我试图将累tang的特性确定下来,留下了上下层或下层,汇编者不断说,它无法找到一个固定的装置,为累犯确定这些财产的价值。

我已经研究了与此相关的其他中继问题,没有找到一个很好的答案。

我想能够确定它是顶端的、底层的、正确的,或留下能够做以下事情的价值。

dragRect.right := dragRect.left;
dragRect.bottom := dragRect.top;

显然,你可以这样做。你们如何在德尔菲斯帝国主义方面取得同样的成就?

Answer 1

As Hans Passant pointed out, it is important to understand the difference between value type and reference type. Because System.Drawing.Rectangle doesn t have setters for left, top, right or bottom, you simply can t set any values to them but only read what is already there. The only time they get updated is when you actually create the Rectangle object passing the height, width and X-Y points OR setting X, Y, height and/or width of a rectangle properties.

由于在我的方案中,我只是试图界定划定边界或地区,以图形,我确定了X、Y、宽度或高度。罚款。就直径的宽度和高度而言,你一度放大,一度高。每当你重新确定 rec子的X和(或)Y值时,就保持其宽度和高度。因此,它知道它的权利和底价值是什么。

For instance, you can do this:

dragRect.X := 100;
dragRect.width := 10;

but you can t do this:

dragRect.left := 100;
dragRect.right :=110;

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