Trying to filter a dropdown list

Question

Here's what I'm doing to declare:

List

With multiple add statements like:

RegressionScenariolist.Add(

This list is sorted with:

RegressionScenariolist = RegressionScenariolist.OrderBy(sc => sc.TestName).Select(sc => sc).ToList();

This list has the potential to become huge.  I need to find a clear example on how I might filter this list down based on the value from another object.

new RegressionTestItem() { TestName = "What my test name is", Driver = new TheDriverScriptName() });<RegressionTestItem> RegressionScenariolist = new List<RegressionTestItem>();