因为在我的某个工具包里需要能动态执行一段代码进行求值的功能，也就是类似于JAVA SCRIPT里的Eval函数和VB SCRIPT的Execute函数功能，但C#与VB.NET却没有类似的函数:( 只能手动编写。上网搜索了一下，幸运的从一个英文站点找到了：）代码量很少，它是通过调用JScript.NET里的Eval函数进行处理的，下面是代码(部分代码我修改与删减过，并非完整的原代码，在此感谢原作者scott）：
using
System;
using
System.CodeDom.Compiler;
using
System.Reflection;
/// <summary>
/// 动态求值
/// </summary>
public
class
Evaluator
{
/// <summary>
/// 计算结果,如果表达式出错则抛出异常
/// </summary>
/// <param name="statement">表达式,如"1+2+3+4"</param>
/// <returns>结果</returns>
public static object Eval(string statement)
{
return _evaluatorType.InvokeMember(
"Eval",
BindingFlags.InvokeMethod,
null,
_evaluator,
new object[] { statement }
);
}
/// <summary>
///
/// </summary>
static Evaluator()
{
//构造JScript的编译驱动代码
CodeDomProvider provider = CodeDomProvider.CreateProvider("JScript");
CompilerParameters parameters;
parameters = new CompilerParameters();
parameters.GenerateInMemory = true;
CompilerResults results;
results = provider.CompileAssemblyFromSource(parameters, _jscriptSource);
Assembly assembly = results.CompiledAssembly;
_evaluatorType = assembly.GetType("Evaluator");
_evaluator = Activator.CreateInstance(_evaluatorType);
}
private static object _evaluator = null;
private static Type _evaluatorType = null;
/// <summary>
/// JScript代码
/// </summary>
private static readonly string _jscriptSource =
@"class Evaluator
{
public function Eval(expr : String) : String
{
return eval(expr);
}
}";
}
using
System;
using
System.CodeDom.Compiler;
using
System.Reflection;
/// <summary> /// 动态求值 /// </summary>
public
class
Evaluator
{ /// <summary> /// 计算结果,如果表达式出错则抛出异常 /// </summary> /// <param name="statement">表达式,如"1+2+3+4"</param> /// <returns>结果</returns> public static object Eval(string statement) { return _evaluatorType.InvokeMember( "Eval", BindingFlags.InvokeMethod, null, _evaluator, new object[] { statement } ); } /// <summary> /// /// </summary> static Evaluator() { //构造JScript的编译驱动代码 CodeDomProvider provider = CodeDomProvider.CreateProvider("JScript"); CompilerParameters parameters; parameters = new CompilerParameters(); parameters.GenerateInMemory = true; CompilerResults results; results = provider.CompileAssemblyFromSource(parameters, _jscriptSource); Assembly assembly = results.CompiledAssembly; _evaluatorType = assembly.GetType("Evaluator"); _evaluator = Activator.CreateInstance(_evaluatorType); } private static object _evaluator = null; private static Type _evaluatorType = null; /// <summary> /// JScript代码 /// </summary> private static readonly string _jscriptSource = @"class Evaluator { public function Eval(expr : String) : String { return eval(expr); } }"; }
本文转自Kingthy博客园博客，原文链接：http://www.cnblogs.com/kingthy/archive/2007/12/15/995641.html
，如需转载请自行联系原作者
