Some links for help :

1: Microsoft site;
2: Microsoft forum about Regular Expressions in VS Studio;
3: An article ;
4: Test Your Regular Expression online using .NET Engine;

My Examples:

1: Find: gex.CustomInfo.Add\({["a-zA-Z0-9_]*}{:Po[:Zs]*}{[a-zA-Z0-9_]*}\)
    Replace: gex.CustomInfo.Add(\1\2\3.ToString())

   gex.CustomInfo.Add(”MuniName”, MuniName)   -> gex.CustomInfo.Add(”MuniName”, MuniName.ToString())

2: Find: Rows\({["a-zA-Z0-9_]*}\).Item\({["a-zA-Z0-9_]*}\)
    Replace : Rows[\1][\2]

    Rows(”aaa”).Item(”jjj”)   -> Rows["aaa"]["jjj"]