Hello, Cocoa discourages the subclassing of NSTextField, so delegation to a formatter is much more better.
For your purpose, you can use the NSNumberFormatter or create your own NSFormatter subclass. See http://developer.apple.com/DOCUMENTATION/Cocoa/Conceptual/DataFormatting/Articles/CreatingACustomFormatter.html#//apple_ref/doc/uid/20000196or http://developer.apple.com/DOCUMENTATION/Cocoa/Reference/Foundation/Classes/NSFormatter_Class/Reference/Reference.html#//apple_ref/doc/uid/20000204-DontLinkElementID_4for details. The NSFormatter class gives you to validate and/or alter the text field content. Regards, Laurent Etiemble. 2008/12/15 Nick Ifloat <[email protected]> > Please help me with building an equivalent to the Numbers only input > validation code for using with NSTextField using Monobjc. > > Case: I want the NSTextField to allow the user to input only numbers(0 to > 9), '.' and '-' symbols. > > Request: Well I am stuck. I am able to handle key press events in Windows > Forms and Gtk#. But I am new to Mac OS X and need your help with building an > equivalent method to handle key press events on Mac OS X using Monobjc. I am > providing my sample code of key press event handler using Windows Forms and > Gtk# bellow. (I have read about NSFormater, NSCell, NSView's keyDown method > - but I can't seem to find my way on doing the same using Monobjc!) > > Provided: 1. Windows Forms & 2. Gtk# numbers only input sample code. > > Need: Monobjc code for numbers only input validation sample code. > > //Windows Forms Code to handle KeyPressEvents > > private void OnlyNumbers(KeyPressEventArgs e) > { > char c = e.KeyChar; > if (!(c >= '0' && c <= '9' || c == '.' || c == '-' || c == 8)) > //8 is the keycode of the backspace key > { > e.Handled = true; > } > } > > //Then I am calling the method on the text fields KeyPress handler > > private void txtNumber_KeyPress(object sender, KeyPressEventArgs e) > { > OnlyNumbers(e); > } > > //End of Windows Forms Code > > //Gtk# Code to handle/capture & kill Unwanted Keys > > private void OnlyNumbers(object o, Gtk.TextInsertedArgs > args)//[GLib.ConnectBefore]Gtk. > { > try > { > Console.WriteLine("text : " + > args.Text.ToString()); > int pos = ((Entry)o).Position; > string c = ((Entry)o).GetChars(pos, pos+1); > char d; > Char.TryParse(c[0].ToString(), out d); > if (!(d >= '0' && d <= '9' || d == '.' || d > == '-')) > { > ((Entry)o).SelectRegion(pos, pos+1); > ((Entry)o).DeleteSelection(); > } > } > catch (System.IndexOutOfRangeException e) {} > } > > //Then I am passing the method to the textfields OnTextInserted event > handler > > protected virtual void txtNumber_OnTextInserted (object o, > Gtk.TextInsertedArgs args) > { > OnlyNumbers(o, args); > } > //End of Gtk# code >
