SelectList. How to find value?

[shapper]

Hello,

I created the following SelectList:

var targets = new Dictionary<string, string>();
targets.Add("New Window", "_blank");
targets.Add("SameWindow", "_self");
viewData.Targets = new SelectList(targets, "Value", "Key");

Given a MyVarKey = "_blank" how can I find in the list the Value for
this Key and return it to MyVarValue?

Thanks,
Miguel