How can I evaluate a C# expression dynamically?

Question

I would like to do the equivalent of:

object result = Eval(\"1 + 3\");
string now    = Eval(\"System.DateTime.Now().ToString()\") as string

Answer 1

If you specifically want to call into code and assemblies in your own project I would advocate using the C# CodeDom CodeProvider.

Here is a list of the most popular approaches that I am aware of for evaluating string expressions dynamically in C#.

Microsoft Solutions

• C# CodeDom CodeProvider:
  • See How LINQ used to work and this CodeProject article
• Roslyn:
  • See this article on Rosly Emit API and this StackOverflow answer
• DataTable.Compute:
  • See this answer on StackOverflow
• Webbrowser.Document.InvokeScript
  • See this StackOverflow question
• DataBinder.Eval
• ScriptControl
  • See this answer on StackOverflow and this question
• Executing PowerShell:
  • See this CodeProject article

Non-Microsoft solutions (not that there is anything wrong with that)

• Expression evaluation libraries:
  • Flee
  • DynamicExpresso
  • NCalc
  • CodingSeb.ExpressionEvaluator
  • Eval-Expression.NET
• Javascript interpreter
  • Jint
• To execute real C#
  • CS-Script
• Roll your own a language building toolkit like:
  • Irony
  • Jigsaw