Cross Thread operations

For quiet some time now I have been using random ways to doing begin invoke. Here is a good pattern for it.

   1: public partial class Form1 : Form

   2: {

   3:     public Form1()

   4:     {

   5:         InitializeComponent();

   6:     }

   7:  

   8:     private void Form1_Load(object sender, EventArgs e)

   9:     {

  10:         ControlsHelper.SafeGui(this, delegate()

  11:         {

  12:             textBox1.Text = "using ControlsHelper on UI thread"; // this succeeds

  13:         });

  14:         Thread t = new Thread(new ThreadStart(WorkOnNewThread));

  15:         t.Start();

  16:     }

  17:     private void WorkOnNewThread()

  18:     {

  19:         ControlsHelper.SafeGui(this, delegate()

  20:         {

  21:             textBox1.Text = "using ControlsHelper"; // this succeeds

  22:         });

  23:  

  24:         textBox1.Text = "direct"; // this fails

  25:     }

  26: }

  27:  

  28: public static class ControlsHelper

  29: {

  30:     public static void SafeGui(Control control, MethodInvoker invoker)

  31:     {

  32:         if (null == invoker) return;

  33:         if (control != null)

  34:         {

  35:             if (control.InvokeRequired)

  36:                 control.BeginInvoke(invoker, null);

  37:             else

  38:                 invoker();

  39:         }

  40:         else

  41:             invoker();

  42:     }

  43: }

Language Recognition

A friend recently had to work with expressions, and he was looking around for some existing libraries which would let him do this. That's when he found ANTLR (http://www.antlr.org).

From the website :

ANTLR, ANother Tool for Language Recognition, is a language tool that provides a framework for constructing recognizers, interpreters, compilers, and translators from grammatical descriptions containing actions in a variety of target languages. ANTLR provides excellent support for tree construction, tree walking, translation, error recovery, and error reporting.

I tried to work with it ANTLR today and I think it is pretty good. One good thing about it is that it also has a GUI to write the grammar, once your grammar is ready, you can generate code in a number of languages.

My primary development language is C# so I was very happy to see that they have also explained how to tweak .csproj and compile the grammar in a visual studio project.

Lazy me

One whole week has gone by... and I have still not started "A pattern a week". I read a bit of  "Elements of Reusable Object-Oriented Software" and it has list of some simplest and most common patterns which one should start of with. They are :

Abstract Factory

Adapter

Composite

Decorator

Factory Method

Observer

Strategy

Template Method

So for this week it is Abstract Factory.