C#: How to make sure a settings variable exists before attempting to use it from another assembly?

Question

I have the following:

using CommonSettings = MyProject.Commons.Settings;

public class Foo
{
    public static void DoSomething(string str)
    {
        //How d         


        

Answer 1

try
{
    var x = Settings.Default[bonusMalusTypeKey]);
}
catch (SettingsPropertyNotFoundException ex)
{
    // Ignore this exception (return default value that was set)
}