WinAPI edit control doesn't display newlines

Question

Well, that's only half true. Newlines work fine for the most part, but when I load a file into it, none of the newlines are shown. Copying the text and pasting it into Notepad++ with view all characters turned on shows that the carriage return and line feed are there.

My loading code:

void open_file(HWND hwnd,const char* fname){
    SendMessage(textbox,WM_SETTEXT,(WPARAM)0,(LPARAM)"");
    FILE* file=fopen(fname,"r");
    fullpath=fname;
    filename=fullpath.substr(fullpath.rfind('\\')+1,fullpath.length());
    int pos;
    while(!feof(file)){
        pos=GetWindowTextLength(textbox);
        SendMessage(textbox,EM_SETSEL,pos,pos);
        fread(buffer,2048,sizeof(char),file);
        SendMessage(textbox,EM_REPLACESEL,false,(LPARAM)buffer);}
    fclose(file);
    SendMessage(hwnd,WM_SETTEXT,0,(LPARAM)filename.c_str());}

Edit controls use \r\n from memory. Check the file doesn't use only \r. Verify you can manually add new lines to the edit control. What styles did you use to create the control? — Boofhead, Jun 26 '11 at 08:45
what makes you think the buffer from fread contains zero-terminated string? besides, don't update piecewise. just call SetWindowText. — Cheers and hth. - Alf, Jun 26 '11 at 08:46
The code is borked. But if you see no line breaks at all then you forgot to turn on the ES_MULTILINE style for the editbox. — Hans Passant, Jun 26 '11 at 14:55

Cheers and hth. - Alf · Accepted Answer · 2011-06-26T09:12:38.167

Since you're opening the file in text mode your text represents newline by \n. Possibly the text edit control requires \r\n.

One possibility is to do like this (off the cuff)

std::string line;
std::ifstream file( fname );
while( std::getline( file, line ) )
{
    line += "\r\n";
    // Append  the line to the edit control here (use c_str() ).
}

But better, set the text all at once, like:

std::string line;
std::string text;
std::ifstream file( fname );
while( std::getline( file, line ) )
{
    line += "\r\n";
    text += line;
}
SetWindowText( textbox, text.c_str() ... whatever );  // Not sure of args, check docs.

Cheers & hth.,

WinAPI edit control doesn't display newlines

1 Answers1