GrabTextFromEdit()

[qhimq]

char* GrabTextFromEdit(int nResourceID, HWND hwndMain) 
{
    int len = GetWindowTextLength(GetDlgItem(hwndMain, nResourceID));
    if (len > 0) 
    {
        char* buffer;
        buffer = (char*)GlobalAlloc(GPTR, len + 1);
        GetDlgItemText(hwndMain, nResourceID, buffer, len + 1);
        return buffer;
    }
}
 

Hi,

If use this function to get text from an edit control made from a dialog that is empty, I get what I want, a char* filled with "(null)". I thought that was nice, but then when I use this same function to get text from an edit control made on runtime (createwindow) then I get a null pointer as a return.

Have any ideas on how to recognize if the edit box is empty?

Sure, I could use the catch/try, but, long story short, in this situation I don't want to use it.

[qhimq]

ah, Ok i figured it out.

What i'm attempting to do, is once the user inputs a value in the textbox and presses enter, the program adds another row of inputs and stuff. I am programming it to add an infinite amount of inputs, so I figured that I would just have the text box resource number be added by 1 each new edit box, and be calculated it's position by the preceding resource number's position.

So I have it attempt to get the text from a textbox that might exist. Then it checks if the resource exists. From that we can find out whether the textbox is either non-existent in the resources or existent in the resources but empty.

I don't have anything complete but here is the foundation.

void AddRow(HWND hwnd)
{
    bool con=true;
    char* str;
    try{ 
    str=GrabTextFromEdit(902, hwnd); 
    if( str == 0 )
         throw "Memory allocation failure!";
    else
        printf("add new row");
    }
    catch(...){
    con=false;
    printf("\n NULL CHAR \n  ,");
    }
 
 
    if(con)
        printf(str);
 
    bool resFound=false;
    if(GetDlgItem(hwnd, 902)==0)
    {
        printf(" resource not found ");
        resFound=false;
    }    
    else
    {
        printf(" resource found ");
        resFound=true;
    }
 
    if(resFound && !con)
    {
        printf("\n empty field \n");
    }
 
}
 

[weaknessforcats]

char* GrabTextFromEdit(int nResourceID, HWND hwndMain)
{
int len = GetWindowTextLength(GetDlgItem(hwndMain, nResourceID));
if (len > 0)
{
char* buffer;
buffer = (char*)GlobalAlloc(GPTR, len + 1);
GetDlgItemText(hwndMain, nResourceID, buffer, len + 1);
return buffer;
}
}

Not all paths return a char*. If len is not greater than 0, nothing is returned. How are you getting this to compile???

Also, since this is C you should be using malloc() rather than GlobalAlloc() which ius much slower.

[Savage]

Not all paths return a char*. If len is not greater than 0, nothing is returned. How are you getting this to compile???

Also, since this is C you should be using malloc() rather than GlobalAlloc() which ius much slower.

I'm not sure that he is uing C,look in his last post.There is try{ and }catch things which are specific to C++..

Savage

[weaknessforcats]

I'm not sure that he is uing C,look in his last post.There is try{ and }catch things which are specific to C++..

Yeah, I saw that. I also saw the typecast in GlobalAlloc() and the fact that everything else is in C.

In fact, try/catch might not work. Microsoft uses structured exceptions __try/__except and there's no throw. You use RaiseException() instead.

[qhimq]

This looks better:

char* GrabTextFromEdit(int nResourceID, HWND hwndMain) 
{
    HWND temp=GetDlgItem(hwndMain, nResourceID);
    if(temp==0)
        return "(none)";//resource not found
    int len = GetWindowTextLength(temp);
    if (len > 0) 
    {
        char* buffer;
        buffer = (char*)GlobalAlloc(GPTR, len + 1);
        GetDlgItemText(hwndMain, nResourceID, buffer, len + 1);
        return buffer;
    }
    return "(empty)";
}
 
 
void AddRow(HWND hwnd)
{//check next resource to see if its there.  if resource found then check next resource etc. if not found add the resource.  
////if resource is empty do nothing.
    char* str=GrabTextFromEdit(903, hwnd); 
 
    if(lstrcmp(str, "(none)") == 0)
        printf("resource not found: So add it\n");
    else if(lstrcmp(str, "(empty)") == 0)
        printf("empty field\n");
    else
        printf("Found: %s : Check next resource if we can Add\n", str);
}
 

[qhimq]

*shrug* it compiles. Its c++ to my understanding.

[weaknessforcats]

char* GrabTextFromEdit(int nResourceID, HWND hwndMain)
{
HWND temp=GetDlgItem(hwndMain, nResourceID);
if(temp==0)
return "(none)";//resource not found
int len = GetWindowTextLength(temp);
if (len > 0)
{
char* buffer;
buffer = (char*)GlobalAlloc(GPTR, len + 1);
GetDlgItemText(hwndMain, nResourceID, buffer, len + 1);
return buffer;
}
return "(empty)"; <<<<< 0 ???
}

Might I suggest you return a zero rather than a pointer to a literal "empty"?

Whereever you use the return from this function you will have to compare "empty" to the char* using something like strcmp(). By returning a 0 all you need do is check the pointer for null before using it.

[qhimq]

I did that the first time, however I didn't want to confuse myself with that later.

Because I need to know if the resource is either empty or non-existent. These two cases are completely different for my program flow.