<p>We're working on a Log Viewer. The use will have the option to filter by user, severity, etc. In the Sql days I'd add to the query string, but I want to do it with Linq. How can I conditionally add where-clauses?</p>

Just use C#'s && operator:
```
```
var items = dc.Users.Where(l => l.Date == DateTime.Today && l.Severity == "Critical")
```
```
Edit: Ah, need to read more carefully. You wanted to know how to
conditionally
add additional clauses. In that case, I have no idea. :) What I'd probably do is just prepare several queries, and execute the right one, depending on what I ended up needing.