1、为了反射，定义一个接口

public interface IRunExpression

 {

Hashtable MainRun(bool IsDebug);

int Precision

  {set;get;}

}

2、生成数据库内容的dll，在这里将内容先写死，可以直接从数据库读取

StringBuilder _SB = new StringBuilder();

//加载引用

    _SB.Append("using System;   \r\n");

    _SB.Append("using System.Collections ;   \r\n");

    _SB.Append("using System.Threading;   \r\n");

    _SB.Append("using System.IO;  \r\n");

    _SB.Append("using System.Text;   \r\n");

    _SB.Append("using System.Data;   \r\n");

//namespace开始

    _SB.Append("namespace CodeCompile   \r\n");

    _SB.Append("{   \r\n");

    _SB.Append("public class RunExpression : IRunExpression  \r\n");

    _SB.Append("{   \r\n");

    _SB.Append("public RunExpression()  \r\n");

    _SB.Append("{   \r\n");

    _SB.Append("}   \r\n");

 //简单的属性

    _SB.Append("private int _Precision; \r\n");

    _SB.Append("public int Precision \r\n");

    _SB.Append("{   \r\n");

    _SB.Append("set{_Precision=value;} \r\n");

    _SB.Append("get{return _Precision;} \r\n");

    _SB.Append("}   \r\n");

//简单方法实现

   _SB.Append("public Hashtable MainRun(bool IsDebug){return new Hashtable();} \r\n");

    _SB.Append(" }  \r\n");

    _SB.Append("}  \r\n");

string CodeContent = _SB.ToString();   //需要编译的内容

//下面的内容需要using Microsoft.CSharp;

CSharpCodeProvider _SCP = new CSharpCodeProvider();

    CompilerParameters _CP = new CompilerParameters();

    _CP.GenerateExecutable = false;

    _CP.MainClass = "CodeCompile.RunExpression";

    //获取生成路径：）

    Assembly a1 = Assembly.GetExecutingAssembly();

    string e1 = a1.CodeBase ;

    int m = e1.IndexOf(@"///") + 3;

    int n = e1.Length;

    e1 = e1.Substring(m,n - m);

    string[] all = e1.Split(new char[]{'/'});

    string prefix = "";

    for(int i=0;i<all.Length-1;i++)

    {

     prefix += all[i] + "/";

    }

    _CP.OutputAssembly = prefix + "RunExpressionTest.DLL";

    _CP.IncludeDebugInformation = true;

    _CP.ReferencedAssemblies.Add( "System.dll" );

    _CP.ReferencedAssemblies.Add( "System.Data.dll" );

    _CP.ReferencedAssemblies.Add( "System.Web.dll" );

    _CP.ReferencedAssemblies.Add( "System.XML.dll" );

   

    _CP.GenerateInMemory = false;

    _CP.WarningLevel = 3;

    _CP.TreatWarningsAsErrors = false;

   

    _CP.CompilerOptions = "/optimize";

    _CP.TempFiles = new TempFileCollection( prefix + @"\temp", true);  //把编译的过程文件放到temp目录。

    CompilerResults _CR = _SCP.CreateCompiler().CompileAssemblyFromSource(_CP,CodeContent);

    System.Collections.Specialized.StringCollection _SC = _CR.Output;

    CompilerErrorCollection _EC = _CR.Errors;

3、OK，内容编译完成，下面是对它的调用

string AssemblyName = "RunExpressionTest.DLL";

ObjectHandle M = Activator.CreateInstance(AssemblyName,"CodeCompile.RunExpression");

IRunExpression _IRE = (IRunExpression)M.Unwrap();

_IRE.Precision = 2;

Hashtable _HTreturn = _IRE.MainRun(true);