Radiobuttons and listbox problem

On my program, I want it so that when the user clicks something in the listbox, the program will switch to another radiobutton. Here's the code i used, but for some reason, it does not work.

Code:

	case WM_COMMAND:

		if ((HWND)lParam == GetDlgItem(hwnd,ID_LIST_CHAN) ){
	      switch(HIWORD(wParam)) {
			case EN_CHANGE:
		    cha_len=SendMessage(GetDlgItem(hwnd,ID_LIST_CHAN),LB_GETCOUNT,0,0);
			if(win_clicked==1)
			{
				if(all_channels==1){
			       //for(i=0;i<cha_len;i++)
				   //{
					   //SelectChange=SendMessage(GetDlgItem(hwnd,ID_LIST_CHAN),LB_GETSEL,i,0);

					   //if(SelectChange<=0)
					   //{

						   SendDlgItemMessage(hwnd, ID_ALL_CHAN, BM_SETCHECK, 0, 0);
                           SendDlgItemMessage(hwnd, ID_ALLMATCH_CHAN, BM_SETCHECK, 0, 0);
		                   SendDlgItemMessage(hwnd, ID_CHAN, BM_SETCHECK, 1, 0);
		                   EnableWindow(GetDlgItem(hwnd,ID_CHAN_COMBO),FALSE);
						   all_channels=0;
						   match_channels=0;
					   //}


				   //}

				}

>>I want it so that when the user clicks something in the listbox<<

So why are you checking for EN_CHANGE which is an edit control notification message? You'll find there's a pattern in the naming of window messages (see table on this page, but note that not all prefixes are listed) which should help you decide which ones are relevant to which controls.

For listboxes the prefixes are LB_ and LBN_ (notification) so clearly what you need to use is the correct listbox notification message to detect when the selection has changed: in this particular situation LBN_SELCHANGE.

Thanks Ken, that really helped! :-)