Win32 – 将文本附加到编辑控件
尝试将文本附加到对话框内的编辑控件。 我无法正确追加_tcscat_s。 它崩溃并说一些关于缓冲区太小或关于空终止字符串的事情。
int WINAPI WinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow ) { return DialogBox( hInstance, MAKEINTRESOURCE( IDD_MAIN ), NULL, DlgProc ); } BOOL CALLBACK DlgProc( HWND hwnd, UINT Message, WPARAM wParam, LPARAM lParam ) { switch( Message ) { case WM_INITDIALOG: OpenAndReadFile( hwnd ); return TRUE; case WM_COMMAND: switch( LOWORD( wParam ) ) { case IDSTART: EndDialog( hwnd, IDSTART ); break; case IDQUIT: EndDialog( hwnd, IDQUIT ); break; } break; case WM_CLOSE: EndDialog( hwnd, 0 ); break; default: return FALSE; } return TRUE; } BOOL OpenAndReadFile( const HWND &hwnd ) { // Open the file HANDLE hFile; hFile = CreateFile( TEXT( "sites.txt" ), // file to open GENERIC_READ, // open for reading FILE_SHARE_READ, // share for reading NULL, // default security OPEN_EXISTING, // existing file only FILE_ATTRIBUTE_NORMAL, // normal file NULL ); // no attr. template if ( hFile == INVALID_HANDLE_VALUE ) { SetDlgItemText( hwnd, IDC_OUTPUT, TEXT( "Error: File could not be opened\r\n" ) ); return FALSE; } else SetDlgItemText( hwnd, IDC_OUTPUT, TEXT( "sites.txt opened\r\n" ) ); AppendText( hwnd, TEXT("TEXT") ); // Read data from file const DWORD BUFFERSIZE = GetFileSize( hFile, NULL ); char *ReadBuffer = new char [BUFFERSIZE](); DWORD dwBytesRead = 0; // read one character less than the buffer size to save room for the // terminate NULL character. //if ( FALSE == ReadFile( hFile, ReadBuffer, BUFFERSIZE - 1, &dwBytesRead, NULL ) ) { } return TRUE; } void AppendText( const HWND &hwnd, TCHAR *newText ) { // get size to determine buffer size int outLength = GetWindowTextLength( GetDlgItem( hwnd, IDC_OUTPUT ) ); // create buffer to hold current text in edit control TCHAR * buf = ( TCHAR * ) GlobalAlloc( GPTR, outLength + 1 ); // get existing text from edit control and put into buffer GetDlgItemText( hwnd, IDC_OUTPUT, buf, outLength + 1 ); // append the newText to the buffer _tcscat_s( buf, outLength + 1, newText ); // Set the text in the dialog SetDlgItemText( hwnd, IDC_OUTPUT, buf ); } GetWindowTextLength()返回文本中TCHAR元素的数量，但GlobalAlloc()需要字节数。 如果您正在编译Unicode，则TCHAR是2个字节，而不是1个字节，但您没有考虑到这一点。 您也没有足够大的缓冲区来保存现有文本和附加的新文本。 您还泄漏了分配的内存。
试试这个：
void AppendText( const HWND &hwnd, TCHAR *newText ) { // get edit control from dialog HWND hwndOutput = GetDlgItem( hwnd, IDC_OUTPUT ); // get new length to determine buffer size int outLength = GetWindowTextLength( hwndOutput ) + lstrlen(newText) + 1; // create buffer to hold current and new text TCHAR * buf = ( TCHAR * ) GlobalAlloc( GPTR, outLength * sizeof(TCHAR) ); if (!buf) return; // get existing text from edit control and put into buffer GetWindowText( hwndOutput, buf, outLength ); // append the newText to the buffer _tcscat_s( buf, outLength, newText ); // Set the text in the edit control SetWindowText( hwndOutput, buf ); // free the buffer GlobalFree( buf ); }
或者：
#include void AppendText( const HWND &hwnd, TCHAR *newText ) { // get edit control from dialog HWND hwndOutput = GetDlgItem( hwnd, IDC_OUTPUT ); // get new length to determine buffer size int outLength = GetWindowTextLength( hwndOutput ) + lstrlen(newText) + 1; // create buffer to hold current and new text std::vector buf( outLength ); TCHAR *pbuf = &buf[0]; // get existing text from edit control and put into buffer GetWindowText( hwndOutput, pbuf, outLength ); // append the newText to the buffer _tcscat_s( pbuf, outLength, newText ); // Set the text in the edit control SetWindowText( hwndOutput, pbuf ); }
话虽如此，将窗口的当前文本放入内存，附加到它，然后替换窗口的文本是将文本追加到编辑控件的一种非常低效的方法。 请改用EM_REPLACESEL消息：
void AppendText( const HWND &hwnd, TCHAR *newText ) { // get edit control from dialog HWND hwndOutput = GetDlgItem( hwnd, IDC_OUTPUT ); // get the current selection DWORD StartPos, EndPos; SendMessage( hwndOutput, EM_GETSEL, reinterpret_cast(&StartPos), reinterpret_cast (&EndPos) ); // move the caret to the end of the text int outLength = GetWindowTextLength( hwndOutput ); SendMessage( hwndOutput, EM_SETSEL, outLength, outLength ); // insert the text at the new caret position SendMessage( hwndOutput, EM_REPLACESEL, TRUE, reinterpret_cast(newText) ); // restore the previous selection SendMessage( hwndOutput, EM_SETSEL, StartPos, EndPos ); }
http://support.microsoft.com/kb/109550
你的答案是：
string buffer = "append this!" HWND hEdit = GetDlgItem (hDlg, ID_EDIT); int index = GetWindowTextLength (hEdit); SetFocus (hEdit); // set focus SendMessageA(hEdit, EM_SETSEL, (WPARAM)index, (LPARAM)index); // set selection - end of text SendMessageA(hEdit, EM_REPLACESEL, 0, (LPARAM)buffer.c_str()); // append!