原文：http://www.cnblogs.com/minbear/archive/2004/05/12/9058.aspx

将資料庫中的.net原碼進行動态編譯及調用~

1、為了反射，定義一個接口

public interface IRunExpression

 {

Hashtable MainRun(bool IsDebug);

int Precision

  {set;get;}

}

2、生成資料庫内容的dll，在這裡将内容先寫死，可以直接從資料庫讀取

StringBuilder _SB = new StringBuilder();

//加載引用

    _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開始

    _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");

 //簡單的屬性

    _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");

//簡單方法實作

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

    _SB.Append(" }  /r/n");

    _SB.Append("}  /r/n");

string CodeContent = _SB.ToString();   //需要編譯的内容

//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";

    //擷取生成路徑：）

    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);  //把編譯的過程檔案放到temp目錄。

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

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

    CompilerErrorCollection _EC = _CR.Errors;

3、OK，内容編譯完成，下面是對它的調用

string AssemblyName = "RunExpressionTest.DLL";

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

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

_IRE.Precision = 2;

Hashtable _HTreturn = _IRE.MainRun(true);