我应该如何传递负值SendMessage函数，当他们期待NativeUInt执行？ [英] How should I pass negative values to SendMessage and Perform when they expect a NativeUInt?

问题描述

假设你有code是这样的：

Suppose you have code like this:

Result.X := ACustomMemo.Perform(EM_LINEFROMCHAR, -1, 0); 

Windows API的索赔-1是一个有效的值，使得其返回的有效行。

The Windows API claims "-1" is a valid value that makes it it return the active line.

不过，德尔福这个定义为NaiveUInt和抱怨，如果我尝试传递-1。

However, Delphi has this defined as NaiveUInt and complains if I try to pass -1.

什么是最干净的解决办法？铸造？

What is the cleanest solution to this? Casting?

推荐答案

铸造-1值WPARAM是正确的方式来处理这种情况。

Casting the -1 value to WPARAM is the proper way to handle this case.

 Result.X := ACustomMemo.Perform(EM_LINEFROMCHAR, WPARAM(-1), LPARAM(0));

顺便说一句，delphi的NativeUint定义为WPARAM类型是正确的，因为是在x86和64位无符号的64位无符号32位。

btw, the delphi NativeUint definition for the WPARAM type is correct, because is a unsigned 32-bit on x86 and unsigned 64-bit on x64.

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