Fix if member == null, and EvaluateVariable set Value = null on purpo…

[stg609]

TL;DR

Fix if member == null, and EvaluateVariable set Value = null on purpose, but throw "object has no public Property or Member"

Details

If I evaluate a non existed property like below, an exception will throw.

ExpressionEvaluator evaluator = new ExpressionEvaluator(); evaluator.Variables = new Dictionary<string, object>() { { "obj", new { }} }; // throw an exception like "object has no public Property or Member x ..." Console.WriteLine(evaluator.Evaluate("obj.x")); 

However, our requirement is return null instead of the exception. So I made use of the EvaluateVariable like below :

evaluator.EvaluateVariable += Evaluator_EvaluateVariable; private static void Evaluator_PreEvaluateVariable(object sender, VariablePreEvaluationEventArg e) { e.HasValue = true; e.Value = null; } 

No luck.

[codingseb]

Thank a lot for this @stg609.
I will publish it with next version. I just need to correct some other issues.