TCHAR[]、LPWSTR、LPTSTR 和 GetWindow 文本函数 [英] TCHAR[], LPWSTR, LPTSTR and GetWindow Text function

问题描述

所以 GetWindowText 在 MSDN 上声明如下:

So the GetWindowText is declared on MSDN as follows:

int GetWindowText(      
    HWND hWnd,
    LPTSTR lpString,
    int nMaxCount
);

但是为了使代码工作，我们必须将第二个参数声明为

However for the code to work we have to declare the second parameter as

TCHAR[255] WTitle;

然后调用函数GetWindowText(hWnd,Wtitle,255);LPTSTR 是一个指向 tchar 数组的指针，因此声明 LPTSTR 类似于声明 TCHAR[]?但它不是这样工作的.使用 TCHAR[] 时，程序返回有效的 GetWindowText 结果(它是一个等于标题中符号数的整数).问题是:如何从 TCHAR[] 中获得确切的标题?代码如

and then call the function GetWindowText(hWnd,Wtitle,255); The LPTSTR is a pointer to an array of tchar, so declaring LPTSTR is similar to declaring TCHAR[]? It doesn't work this way though. When using TCHAR[] the program returns valid GetWindowText result (it is an integer equal to the number of symbols in the title). The question is : how can I get the exact title out of TCHAR[] ? Code like

TCHAR[255] WTitle;
cout<< WTitle;

或

cout<< *Wtitle;

返回数字.如何将其与给定的字符串进行比较?

returns numbers. How can I compare this with a given string?

TCHAR[4] Test= __T("TEST")
if (WTitle == Test) do smth

也不起作用.

推荐答案

好的，先来几个定义.

'T' 类型是将计算为 CHAR(单字节)或 WCHAR(双字节)的定义，具体取决于您是否在构建设置中定义了 _UNICODE 符号.目的是让您使用一组源代码同时针对 ANSI 和 UNICODE.

The 'T' types are definitions that will evaluate to either CHAR (single byte) or WCHAR (double-byte), depending upon whether you've got the _UNICODE symbol defined in your build settings. The intent is to let you target both ANSI and UNICODE with a single set of source code.

定义:

TCHAR title[100];
TCHAR * pszTitle;

...不是等价的.第一个定义了一个包含 100 个 TCHAR 的缓冲区.第二个定义了一个指向一个或多个 TCHAR 的指针，但不指向缓冲区.此外，

...are not equivalent. The first defines a buffer of 100 TCHARs. The second defines a pointer to one or more TCHARs, but doesn't point it at a buffer. Further,

sizeof(title) == 100   (or 200, if _UNICODE symbol is defined)
sizeof(pszTitle) == 4  (size of a pointer in Win32)

如果你有这样的函数:

void foo(LPCTSTR str);

...你可以传入以上两个变量中的任何一个:

...you can pass either of the above two variables in:

foo(title);    // passes in the address of title[0]
foo(pszTitle); // passes in a copy of the pointer value

好的，所以您获得数字的原因可能是因为您确实定义了 UNICODE(因此字符很宽)，并且您使用的是 cout，它特定于单字节字符.改用 wcout:

OK, so the reason you're getting numbers is probably because you do have UNICODE defined (so characters are wide), and you're using cout, which is specific to single-byte characters. Use wcout instead:

wcout << title;

最后，这些都行不通:

TCHAR[4] Test == __T("TEST")   ("==" is equality comparison, not assignment)
if (WTitle == Test) do smth    (you're comparing pointers, use wcscmp or similar)

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