看到许多人经常问到这个问题： 怎么由字符串 “126 + (256 - 2^4 )”，或者怎么判断 “115 56 || 14<45”的结果等等，在MSDN上查了查，写了一个Eval类看到许多人经常问到这个问题： 怎么由字符串 “126 + (256 - 2^4 )”，或者怎么判断 “115 56 || 14<45”的结果等等，在MSDN上查了查，写了一个Eval类。
/*****************************************************************
** 文件名:
Eval.cs
** Copyright (c) 1999 -2003
** 创建人:
Phoenix
** 创建日期:
** 修改人:
** 修改日期:
** 描 述:
获取字符串所表示的逻辑意义
** 版 本:1.0
******************************************************************/
using System.CodeDom;
using System.CodeDom.Compiler;
using Microsoft.CSharp;
using System.Reflection;
public class Eval
{
static object GetValue( string value )
{
string codeSnippet = "using System; " + "\r\n" +
"namespace CzG {" + "\r\n" +
" public class Eval" + "\r\n" +
" {" + "\r\n" +
"
public Eval(){} " + "\r\n" +
"
public object GetValue()" + "\r\n" +
"
{" + "\r\n" +
"
return " + value + ";" + "\r\n" +
"
}" + "\r\n" +
" } }";
CodeSnippetCompileUnit unit = new CodeSnippetCompileUnit( codeSnippet );
ICodeCompiler compiler =
new CSharpCodeProvider().CreateCompiler();
CompilerParameters para = new CompilerParameters();
para.ReferencedAssemblies.Add( "System.dll" );
para.GenerateInMemory = true;
para.GenerateExecutable = false;
para.OutputAssembly = "Eval.dll";
Assembly asm = compiler.CompileAssemblyFromDom( para , unit ).CompiledAssembly;
Type type = asm.GetType( "CzG.Eval" );
MethodInfo mi = type.GetMethod( "GetValue" , BindingFlags.Public | BindingFlags.Instance );
object obj = asm.CreateInstance( "CzG.Eval" );
return mi.Invoke( obj , null );
}
}
调用：
Console.WriteLine( Eval.GetValue(“125 -23” ) );
Console.WriteLine( Eval.GetValue(“125<23“ ) );
Output:
102
False
