.net中处理数学表达式

最近需要计算带参数的数学表达式，比如“X+Y+10+sin(Y)”之类的的公式，

原来用VC的一个计算表达式的类，挺方便的，但是在网上找.net居然没找了好久。

不过还是找到两个，一个是这个http://download.youkuaiyun.com/source/346496

上面这个用起来还是比较方便比较快

下面这个是老外写的，动态编译，可以学习，但是处理起来比较慢

 

using  System;
using  System.CodeDom;
using  System.CodeDom.Compiler;
using  Microsoft.CSharp;
using  System.Text;
using  System.Reflection;
using  System.Text.RegularExpressions;

namespace  ADOGuy
... {
    /**//// <summary>
    /// Summary description for Class1.
    /// </summary>
    public class Evaluator
    ...{
        Construction#region Construction
        public Evaluator(EvaluatorItem[] items)
        ...{
            ConstructEvaluator(items);
        }

        public Evaluator(Type returnType, string expression, string name)
        ...{
            EvaluatorItem[] items = ...{ new EvaluatorItem(returnType, expression, name) };
            ConstructEvaluator(items);
        }

        public Evaluator(EvaluatorItem item)
        ...{
            EvaluatorItem[] items = ...{ item };
            ConstructEvaluator(items);
        }

        private void ConstructEvaluator(EvaluatorItem[] items)
        ...{
            ICodeCompiler comp = (new CSharpCodeProvider().CreateCompiler());
            CompilerParameters cp = new CompilerParameters();
            cp.ReferencedAssemblies.Add("system.dll");
            cp.ReferencedAssemblies.Add("system.data.dll");
            cp.ReferencedAssemblies.Add("system.xml.dll");
            cp.GenerateExecutable = false;
            cp.GenerateInMemory = true;

            StringBuilder code = new StringBuilder();
            code.Append("using System;  ");
            code.Append("using System.Data;  ");
            code.Append("using System.Data.SqlClient;  ");
            code.Append("using System.Data.OleDb;  ");
            code.Append("using System.Xml;  ");
            code.Append("namespace ADOGuy {  ");
            code.Append("  public class _Evaluator {  ");
            foreach (EvaluatorItem item in items)
            ...{
                code.AppendFormat("    public {0} {1}() ",
                    item.ReturnType.Name,
                    item.Name);
                code.Append("{ ");
                code.AppendFormat("      return ({0}); ", item.Expression);
                code.Append("} ");
            }
            code.Append("} }");

            CompilerResults cr = comp.CompileAssemblyFromSource(cp, code.ToString());
            if (cr.Errors.HasErrors)
            ...{
                StringBuilder error = new StringBuilder();
                error.Append("Error Compiling Expression: ");
                foreach (CompilerError err in cr.Errors)
                ...{
                    error.AppendFormat("{0} ", err.ErrorText);
                }
                throw new Exception("Error Compiling Expression: " + error.ToString());
            }
            Assembly a = cr.CompiledAssembly;
            _Compiled = a.CreateInstance("ADOGuy._Evaluator");
        }
        #endregion

        Public Members#region Public Members
        public int EvaluateInt(string name)
        ...{
            return (int)Evaluate(name);
        }

        public string EvaluateString(string name)
        ...{
            return (string)Evaluate(name);
        }

        public bool EvaluateBool(string name)
        ...{
            return (bool)Evaluate(name);
        }

        public object Evaluate(string name)
        ...{
            MethodInfo mi = _Compiled.GetType().GetMethod(name);
            return mi.Invoke(_Compiled, null);
        }
        #endregion

        Static Members#region Static Members
        static public int EvaluateToInteger(string code)
        ...{
            Evaluator eval = new Evaluator(typeof(int), code, staticMethodName);
            return (int)eval.Evaluate(staticMethodName);
        }

        static public string EvaluateToString(string code)
        ...{
            Evaluator eval = new Evaluator(typeof(string), code, staticMethodName);
            return (string)eval.Evaluate(staticMethodName);
        }

        static public bool EvaluateToBool(string code)
        ...{
            Evaluator eval = new Evaluator(typeof(bool), code, staticMethodName);
            return (bool)eval.Evaluate(staticMethodName);
        }

        static public object EvaluateToObject(string code)
        ...{
            Evaluator eval = new Evaluator(typeof(object), code, staticMethodName);
            return eval.Evaluate(staticMethodName);
        }
        #endregion

        Private#region Private
        const string staticMethodName = "__foo";
        Type _CompiledType = null;
        object _Compiled = null;
        #endregion
    }

    public class EvaluatorItem
    ...{
        public EvaluatorItem(Type returnType, string expression, string name)
        ...{
            ReturnType = returnType;
            Expression = expression;
            Name = name;
        }

        public Type ReturnType;
        public string Name;
        public string Expression;
    }
}

/**/ ///
     static   int  Compute( string  expression,  params   int [] n)
     ... {
        foreach (int i in n)
            expression = Regex.Replace(expression, @"(?'a'.*?)(?!d)w+(?'b'.*)", "${a}" + i + "${b}");
        ADOGuy.Evaluator calculator = new ADOGuy.Evaluator(typeof(int), expression, "EvaluateInt");
        return calculator.EvaluateInt("EvaluateInt");
    }

                 int  L  =   5 ;
                 int  N  =   10 ;
                 int  SUM  =  Compute( " L + N + 10 " , L, N);
                Console.WriteLine(SUM);
                Console.Read();