01.using System;
02.using System.Reflection;
03.using System.CodeDom.Compiler;
04.using System.Text;
05.using Microsoft.CSharp;
06.
07.namespace CSharpMath
08.{
09. class Calculator
10. {
11. public static double EvaluateExpression(string expression)
12. {
13. StringBuilder Sb = new StringBuilder();
14. Sb.AppendLine("public static class Cal");
15. Sb.AppendLine("{");
16. Sb.AppendLine("\t public static double cal()");
17. Sb.AppendLine("\t {");
18. Sb.AppendFormat("\t\t return {0};", expression);
19. Sb.AppendLine("\t }");
20. Sb.AppendLine("}");
21.
22. string code = Sb.ToString();
23. CompilerResults compilerResults = CompileScript(code);
24.
25. if (compilerResults.Errors.HasErrors)
26. {
27. throw new InvalidOperationException("Expression has a syntax error.");
28. }
29.
30.
31. Assembly assembly = compilerResults.CompiledAssembly;
32. MethodInfo method = assembly.GetType("Cal").GetMethod("cal");
33.
34. return (double)method.Invoke(null, null);
35. }
36.
37.
38. private static CompilerResults CompileScript(string source)
39. {
40. CompilerParameters parms = new CompilerParameters();
41.
42. parms.GenerateExecutable = false;
43. parms.GenerateInMemory = true;
44. parms.IncludeDebugInformation = false;
45.
46. CodeDomProvider compiler = CSharpCodeProvider.CreateProvider("CSharp");
47.
48. return compiler.CompileAssemblyFromSource(parms, source);
49. }
50. }
51.}
