Problem: You are using Select Method to retrieve rows from a typed DataTable and you keep getting the fallowing exception:
System.Data.EvaluateException: Cannot perform '=' operation on System.String and System.Int32.
This isn't the most helpful error message.
Solution: You are missing hyphens.
Example:
Wrong:
CustomerRow[] rows = Select(string.Format("LastName = {0}", LastName)) as CustomerRow[];
Right:
CustomerRow[] rows = Select(string.Format("LastName = '{0}'", LastName)) as CustomerRow[];