counting and then sending a message

[abdul]

I have added a list box on a dialog box with the name "IDLIST"
Now I want to change the text of that dialog when the item(s) are selected in the list box. I used the following code:

int count;
HWND hlist = GetDlgItem(hwnd, IDCLIST);
count = SendMessage(hlist, LB_GETSELCOUNT, 0,0);
int *buffer1 = GlobalAlloc(GPTR, sizeof(int) * count);
SendMessage(hlist, LB_GETSELITEMS, (WPARAM)count, (LPARAM)buffer1);
SetWindowText(hwnd, buffer1);
GlobalFree(buffer1);

But it gives me these errors:

cannot convert from 'void *' to 'int *'
error C2664: 'SetWindowTextA' : cannot convert parameter 2 from 'int *' to 'const char *'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
error C2440: '=' : cannot convert from 'void *' to 'char *'
Conversion from 'void*' to pointer to non-'void' requires an explicit cast


Do you know why its giving me these errors and how can I fix them.

[parksie]

int *buffer1 = GlobalAlloc(GPTR, sizeof(int) * count);
SendMessage(hlist, LB_GETSELITEMS, (WPARAM)count, (LPARAM)buffer1);
SetWindowText(hwnd, buffer1);
GlobalFree(buffer1);

Remember how C++ won't let you arbitrarily assign void* pointers to things? It happens here By the way, you should use new[]/delete[] rather than the Global functions.

[abdul]

And

Remember how C++ won't let you arbitrarily assign void* pointers to things

I did not understand what you meant by that.

[parksie]

In the other thread I explained about the whole int* = void* C/C++ thing.

I'm too tired to do any code now, but you need to use int* buffer1 = new int[count] and delete[] buffer1 in there instead of GlobalAlloc/GlobalFree.

Also, you need to convert the integers to a string first (look around on the forum).

[abdul]

I am unfimiliar with new and delete thingies.

When I use this function:

SendMessage(hlist, LB_GETSELITEMS, (WPARAM)count, (LPARAM)buffer1);

Will it return me the value as an integer or a string (like all the text currently selected)

If it returns as string then why not I just use something like this:

int count;
HWND hlist = GetDlgItem(hwnd, IDCLIST);
count = SendMessage(hlist, LB_GETSELCOUNT, 0,0);
char* buffer1 = (char*)new int[count];
SendMessage(hlist, LB_GETSELITEMS, (WPARAM)count, (LPARAM)buffer1);
SetWindowText(hwnd, buffer1);
delete[] buffer1;
return 0;

It runs fine. But when I select something from the listbox, it gives me an error message. I have included the picture of that error message box in that attachment.

[denniswrenn]

Are you using a multiple selection List Box, or a single selection listbox? If it's the 2nd choice, then you're going about this all wrong.

[abdul]

Yes it is the second choice but I thought that it would work with both of them(single and muliselection) because if there is just one selection then it may count just 1.

Am I doing rong. If yes, then how do I do the other way?

[denniswrenn]

Took me a while to whip up this bit of code, but it works

		int count = 0;
		int i = 0;
		int sel = 0;
		int textlen = 0;
		TCHAR* str;
		HWND hlist = GetDlgItem(hwnd, IDCLIST);

		count = SendMessage(hList, LB_GETCOUNT,0, 0);
		for(i = 0; i < count; i++)
		{
			if(SendMessage(hList,LB_GETSEL,i, 0) > 0)
			{
				sel = i;
				break;
			}
		}
		textlen = SendMessage(hList,LB_GETTEXTLEN,sel, 0);
		str = new TCHAR[textlen];
		SendMessage(hList, LB_GETTEXT, sel, (long)str);
		SetWindowText(hwnd, str);

Don't have much experience using delete[], so you'll have to add that in there yourself...