将写内容过程中比较常用的内容记录起来，如下的内容是关于C#编写的一个简单的命令行计算器的内容，应该对各朋友有用途。
using System;using System.CodeDom.Compiler;using System.Globalization;using System.Reflection;using System.Threading;namespace RobvanderWoude{ class ClCalc { static int Main( string[] args ) { string expression = string.Empty; foreach ( string arg in args ) { expression += " " + arg; } expression = expression.Trim( ); try { Thread.CurrentThread.CurrentCulture = new CultureInfo( "en-US" ); Double result = JScriptEvaluator.EvalToDouble( expression ); Console.WriteLine( "{0} = {1}", expression, result ); try { return Convert.ToInt32( result ); } catch ( Exception ) { return 0; } } catch ( Exception e ) { return WriteError( e.Message ); } } public static int WriteError( Exception e ) { return WriteError( e == null ? null : e.Message ); } public static int WriteError( string errorMessage ) { ClCalc, Version 1.00 Command Line Calculator Usage: CLCALC expression Notes: Result is displayed on screen and returned as exit code ("errorlevel"). Exit code is integer value of result or 0 in case of error or overflow. "Culture" is set to "en-US", so use and expect decimal dots, no commas. Based on Eval function (using JScript) by "markman": www.codeproject.com/Articles/11939/Evaluate-C-Code-Eval-Function Written by Rob van der Woude if ( string.IsNullOrEmpty( errorMessage ) == false ) { Console.Error.WriteLine( ); Console.ForegroundColor = ConsoleColor.Red; Console.Error.Write( "ERROR: " ); Console.ForegroundColor = ConsoleColor.White; Console.Error.WriteLine( errorMessage ); Console.ResetColor( ); } Console.Error.WriteLine( ); Console.Error.WriteLine( "ClCalc, Version 1.00" ); Console.Error.WriteLine( "Command Line Calculator" ); Console.Error.WriteLine( ); Console.Error.Write( "Usage: " ); Console.ForegroundColor = ConsoleColor.White; Console.Error.WriteLine( "CLCALC expression" ); Console.ResetColor( ); Console.Error.WriteLine( ); Console.Error.WriteLine( "Notes: Result is displayed on screen and returned as exit code ("errorlevel")." ); Console.Error.WriteLine( " Exit code is integer value of result or 0 in case of error or overflow." ); Console.Error.WriteLine( " Culture is set to "en-US", so use and expect decimal dots, not commas." ); Console.Error.WriteLine( " Based on Eval function (using JScript) by "markman":" ); Console.ForegroundColor = ConsoleColor.DarkGray; Console.Error.WriteLine( " www.codeproject.com/Articles/11939/Evaluate-C-Code-Eval-Function" ); Console.ResetColor( ); Console.Error.WriteLine( ); Console.Error.WriteLine( "Written by Rob van der Woude" ); return 0; } } public class JScriptEvaluator { public static int EvalToInteger( string statement ) { string s = EvalToString( statement ); return int.Parse( s.ToString( ) ); } public static double EvalToDouble( string statement ) { string s = EvalToString( statement ); return double.Parse( s ); } public static string EvalToString( string statement ) { object o = EvalToObject( statement ); return o.ToString( ); } public static object EvalToObject( string statement ) { return _evaluatorType.InvokeMember( "Eval", BindingFlags.InvokeMethod, null, _evaluator, new object[] { statement } ); } static JScriptEvaluator( ) { CodeDomProvider provider = new Microsoft.JScript.JScriptCodeProvider( ); CompilerParameters parameters; parameters = new CompilerParameters( ); parameters.GenerateInMemory = true; CompilerResults results; results = provider.CompileAssemblyFromSource( parameters, _jscriptSource ); Assembly assembly = results.CompiledAssembly; _evaluatorType = assembly.GetType( "Evaluator.Evaluator" ); _evaluator = Activator.CreateInstance( _evaluatorType ); } private static object _evaluator = null; private static Type _evaluatorType = null; private static readonly string _jscriptSource = @"package Evaluator { class Evaluator { public function Eval(expr : String) : String { return eval(expr); } } }"; }} 复制代码