如何动态评估一个C#的前pression

如何动态评估一个C#的前pression

本文介绍了如何动态评估一个C#的前pression?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

我愿做等价的:

 对象result =的eval(1 + 3);
现在字符串=的eval(System.DateTime.Now()的ToString())作为字符串

继蔽日小号,我得到了这个片段(修改删除过时的方法 I codeCompiler.CreateCompiler()

 私有对象与eval(String性pression)
{
    CSHARP codeProvider C =新CSHARP codeProvider();
    CompilerParameters CP =新CompilerParameters();    cp.ReferencedAssemblies.Add(system.dll中);    cp.CompilerOptions =/ T:库;
    cp.GenerateInMemory = TRUE;    StringBuilder的SB =新的StringBuilder();
    sb.Append(使用系统; \\ n);    sb.Append(命名空间CS codeEvaler {\\ n);
    sb.Append(公共类CS codeEvaler {\\ n);
    sb.Append(公共对象评估和演示code(){\\ n);
    sb.Append(回归+ SEX pression +\\ n);
    sb.Append(} \\ n);
    sb.Append(} \\ n);
    sb.Append(} \\ n);    CompilerResults CR = c.CompileAssemblyFromSource(CP,sb.ToString());
    如果(cr.Errors.Count大于0)
    {
        抛出新InvalidEx pressionException(
            的String.Format(错误({0})评价:{1},
            cr.Errors [0] .ErrorText,性别pression));
    }    System.Reflection.Assembly一个= cr.CompiledAssembly;
    对象o = a.CreateInstance(CS codeEvaler.CS codeEvaler);    类型t = o.GetType();
    MethodInfo的MI = t.GetMethod(评估和演示code);    对象S = mi.Invoke(0,NULL);
    返回S;}


解决方案

通过使用编译的飞行,喜欢的的节目。

或使用,这是完全一样的道理。

I would like to do the equivalent of:

object result = Eval("1 + 3");
string now    = Eval("System.DateTime.Now().ToString()") as string

Following Biri s link, I got this snippet (modified to remove obsolete method ICodeCompiler.CreateCompiler():

private object Eval(string sExpression)
{
    CSharpCodeProvider c = new CSharpCodeProvider();
    CompilerParameters cp = new CompilerParameters();

    cp.ReferencedAssemblies.Add("system.dll");

    cp.CompilerOptions = "/t:library";
    cp.GenerateInMemory = true;

    StringBuilder sb = new StringBuilder("");
    sb.Append("using System;\n");

    sb.Append("namespace CSCodeEvaler{ \n");
    sb.Append("public class CSCodeEvaler{ \n");
    sb.Append("public object EvalCode(){\n");
    sb.Append("return " + sExpression + "; \n");
    sb.Append("} \n");
    sb.Append("} \n");
    sb.Append("}\n");

    CompilerResults cr = c.CompileAssemblyFromSource(cp, sb.ToString());
    if (cr.Errors.Count > 0)
    {
        throw new InvalidExpressionException(
            string.Format("Error ({0}) evaluating: {1}",
            cr.Errors[0].ErrorText, sExpression));
    }

    System.Reflection.Assembly a = cr.CompiledAssembly;
    object o = a.CreateInstance("CSCodeEvaler.CSCodeEvaler");

    Type t = o.GetType();
    MethodInfo mi = t.GetMethod("EvalCode");

    object s = mi.Invoke(o, null);
    return s;

}
解决方案

By using compile on the fly, like this example shows.

Or by using Flee, which is for exactly the same reason.

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09-12 00:28