C++ Windows : Saving the line of an edit control into a vector of TCHAR

Question

下面的代码工作正常:

int iLength = SendMessage(hWndEdit, EM_LINELENGTH, 0, 0);
if(iLength > 0) {
    TCHAR* szBuffer = new TCHAR[iLength+1];
    iLength = SendMessage(hWndEdit, EM_GETLINE, 0, (LPARAM)szBuffer);
    szBuffer[iLength] = TEXT('\0');
    MessageBox(hWnd, szBuffer, TEXT("Edit content"), MB_OK);
    delete[] szBuffer;
}

现在我想用 std::vector<TCHAR> 做同样的事情:

int iLength = SendMessage(hWndEdit, EM_LINELENGTH, 0, 0);
if(iLength > 0) {
    std::vector<TCHAR> data(iLength+1, TEXT('\0'));
    iLength = SendMessage(hWndEdit, EM_GETLINE, 0, (LPARAM)&data[0]);
    MessageBox(hWnd, &data[0], TEXT("Edit content"), MB_OK);
}

它编译，但在 iLength = SendMessage(hWndEdit, EM_GETLINE, 0, (LPARAM)&data[0]);变量 iLength将始终设置为 0，因此，我的 vector 中不会写入任何内容。

这里有什么问题？提前致谢。

Answer 1

来自 the documentation :

A pointer to the buffer that receives a copy of the line. Before sending the message, set the first word of this buffer to the size, in TCHARs, of the buffer.