| Subject | Re: Grid Navigation |
| From | Mervyn Bick <invalid@invalid.invalid> |
| Date | Mon, 12 Feb 2018 11:06:27 +0200 |
| Newsgroups | dbase.getting-started |
| Attachment(s) | test_grid_callback2.wfm |
On 2018-02-10 10:28 PM, Mustansir Ghor wrote: > Dear All > > I have grid with 5 columns. 1st column is combobox, 2nd column is entryfield, 3rd and 4th are reference display from lookuprowset. 5th is a calculated one based on item selection from 1st column and entryfiled of 2nd column. I therefore wish to restrict navigation to only 2 columns 1st and 2nd. Can anybody advise how this can be achieved. The fact that you have a combobox in your grid suggests that you are using the grid for data entry and/or editing. Over the years I've come to the conclusion that using a grid for editing is not a good idea. It is simply too easy to make mistakes. I prefer to display data in a grid and use entryfields for adding/editing fields in conjunction with Edit, Add, Save and Abandon buttons. Still, if you really want to use a grid for adding/editing rows it can be done. The only way I could restrict navigation to the first two columns of the grid was to use the CALLBACK command. This means this will only work for dBASE Plus 8 and later. (This is where someone, usually Ivar Jesson, pops up with a Better Way than the Bick Way. :-) ) The attached example installs a keyboard "hook". This intercepts all keystrokes to the form by forcing Windows to execute a function in the program in place of it's own function. The program can then monitor all keystrokes including those that the normal onKey and Key event handlers miss. Normally the keystroke is passed straight back to the Windows function but by returning 1 instead of calling the Windows hook the keystroke is ignored by Windows. If the keystroke was Tab or Enter in the second column the function doOnEnter is executed and the Tab or Enter keystroke is not returned to Windows but is dealt with by doOnEnter.. If the user uses the mouse to click in any of the fields column 1 gets focus. Some points to watch The underlying fields for columns 3 - 5 must have their readonly property set true. After the form has been run I've found that the sourcecode editor crashes after changes have been made to the code. The changes are, however, saved first. Close dBASE and restart. It's a PITA but nothing else seems to get hurt. I'll be submitting a bug report later. Mervyn. | |
clear if file('test_grid_callback.dbf') drop table test_grid_callback endif if not file('test_grid_callback.dbf') create table test_grid_callback (job_no character(5),customer character(15),address1 character(15),address2 character(15),address3 character(15)) use test_grid_callback generate 10 go top for n = 1 to 10 replace job_no with '1'+str(N,3,0,'0') SKIP next go top replace customer with 'Abel' SKIP replace customer with 'Baker' SKIP replace customer with 'Charlie' SKIP replace customer with 'Delta' SKIP replace customer with 'Echo' SKIP use endif ** END HEADER -- do not remove this line // // Generated on 2018/02/12 // parameter bModal local f f = new test_rid_callback2Form() if (bModal) f.mdi = false // ensure not MDI f.readModal() else f.open() endif class test_rid_callback2Form of FORM with (this) canClose = class::FORM_CANCLOSE onOpen = class::FORM_ONOPEN onClose = class::FORM_ONCLOSE height = 26.7273 left = 44.2857 top = 3.2273 width = 134.8571 text = "" scrollBar = 2 // Auto endwith this.TEST_GRID_CALLBACK1 = new QUERY(this) with (this.TEST_GRID_CALLBACK1) left = 2.0 top = 1.0 width = 14.0 height = 1.0 sql = 'select * from "test_grid_callback.DBF"' active = true endwith with (this.TEST_GRID_CALLBACK1.rowset) with (fields["address1"]) readOnly = true endwith with (fields["address2"]) readOnly = true endwith with (fields["address3"]) readOnly = true endwith endwith this.GRID1 = new GRID(this) with (this.GRID1) onLeftMouseUp = class::GRID1_ONLEFTMOUSEUP dataLink = form.test_grid_callback1.rowset height = 15.5 left = 12.0 top = 6.0 width = 103.0 endwith this.rowset = this.test_grid_callback1.rowset function form_onClose() form.test_grid_callback1.active = false return function form_onOpen() clear #include winuser.h if type("dBGetCurrentThreadId") # "FP" extern CULONG dBGetCurrentThreadId() kernel32 from "GetCurrentThreadId" endif if type("dBGetWindowLong") # "FP" extern CLONG dBGetWindowLong(CHANDLE, CINT) user32 from "GetWindowLongW" endif if type("dBSetWindowsHookEx") # "FP" extern CLONG dBSetWindowsHookEx(CINT, CPTR, CHANDLE, CULONG) user32 from "SetWindowsHookExW" endif if type("dBUnhookWindowsHookEx") # "FP" extern CLOGICAL dBUnhookWindowsHookEx(CHANDLE) user32 from "UnhookWindowsHookEx" endif if type("dBCallNextHookEx") # "FP" extern CLONG dBCallNextHookEx(CHANDLE, CINT, CUINT, CUINT) user32 from "CallNextHookEx" endif // if type("GetAsyncKeyState") # "FP" // extern CSHORT GetAsyncKeyState(CSHORT) user32 // endif CALLBACK CLONG hookWndProc(CINT, CUINT, CUINT) OBJECT this this.hookProc = GetCallAddress(class::HOOKWNDPROC) this.hInst = dBGetWindowLong(this.hwnd, GWL_HINSTANCE) this.hook = dBSetWindowsHookEx(WH_KEYBOARD, this.hookProc, this.hInst, dBGetCurrentThreadId()) form.grid1.setFocus() return function GRID1_onLeftMouseUP(flags, col, row) keyboard '{tab}' keyboard '{home}' return function form_canClose //detach the hook. dBUnhookWindowsHookEx(this.hook) return true function doOnEnter if form.test_grid_callback1.rowset.atlast() form.test_grid_callback1.rowset.beginAppend() else form.test_grid_callback1.rowset.next() endif keyboard '{home}' return function hookWndproc(hCode, wParam, lParam) cReturn = dBCallNextHookEx(this.hook, hCode, wParam, lParam) if (wParam = VK_RETURN or wParam = VK_TAB) and hcode = 0 and not bitset(lparam,31) if upper(form.activeControl.name) = 'GRID1' and form.grid1.currentcolumn = 2 //tab or return in column 1 is ignored here and passed on to Windows like any other keystroke if form.test_grid_callback1.rowset.state = 3 and form.grid1.currentcolumn = 2 form.test_grid_callback1.rowset.save() endif class::doOnEnter() //Deal with tab or return in coulmn 2 cReturn = 1 // Don't call next hook. This prevents Enter or Tab from moving cursor to next field endif endif return cReturn endclass | |