Question

What is the linq equivalent of a SQL clause like WHERE UserName LIKE 'fr_d'?

I’m working with a dataset in memory rather than a SQL database so I don’t think I can use something like where SqlMethods.Like(p.UserName, "Fr_d")

(Not that my installation of VS2008 is admitting that SqlMethods or even System.Data.Linq.SqlClient
exist at the moment, but thats a whole different problem!)

Answer 1

Like this:

table.Where(row => row.StringColumn.StartsWith("prefix"))

(You may also want to call Contains or EndsWith)

EDIT: In your case, you want

table.Where(p => p.UserName.StartsWith("Fr") && p.UserName.EndsWith("d") && p.UserName.Length == 4)

Alternatively, you can also put a regex inside the Where clause.
If you do, make sure to create the RegEx object outside the Where call so that it doesn’t get parsed for each row.