In SQL Management Studio, you can use expressions like

DECLARE @FirstName NVARCHAR(max)='<Enter FirstName,nvarchar(max),John>';
DECLARE @LastName NVARCHAR(max)='<Enter LastName,nvarchar(max),Doe>';

in a *.SQL file. When you press Ctrl+Shift+M, then you are prompted to enter the parameters in one single dialog (in this case it shows "Enter FirstName", and "Enter LastName" displays default values "John" and "Doe", both of type nvarchar(max))

This is quite useful to have some quickly generated macros at hand, and maybe the idea could be supported in C# for Linq Expressions as well ...