I once heard someone way that once you really get Linq, you’ll won’t ever need to write a For/Each loop again. Probably an overstatement, but still I was intrigued. I set out last night to see how Linq could negate the need for For/Each.

I set out to find a way to create ADO.NET connection strings. In the past, I would have probably used foreach to iterate over a collection using StringBuilder and String.Format to build up the connection string. I dispensed with all that old-school thought and created the connection string as shown below in Figure 1. As a bonus, I also learned (thanks to a little prompting from Resharper) a shortcut for initializing a collection.

The Linq code in lines 10 and 11 is where the cool stuff happens. Each element from the dictionary is selected to create a value pair and the Linq Aggregate() operator is used to concatenate all of the value pairs. All very sweet!

  1var o = new Dictionary< string, string >()

  2	{

  3		{ "Data Source",           "DUFFSQLSERVER2008" },

  4		{ "Initial Catalog",       "Chinook" },

  5		{ "Persist Security Info", "True" },

  6		{ "User ID",               "xxxxx" },

  7		{ "Password",              "xxxxx" }

  8	};    

  9

 10var ConnectionString = o.Select( i => i.Key + "=" + i.Value ).

 11                         Aggregate( ( a, b ) => a + ";" + b );

 12

 13Console.WriteLine( ConnectionString );

I used LinqPad to create and test this code. I just started using LinqPad and can’t believe I ever coded without it. Beyond being a great test bed for Linq, it is a superb snippet compiler. LinqPad is a free download and should be in every coder’s toolbox.