由网友(还你笑眼,)分享简介:我需要解析复杂的EX presion公司从字符串为BOOL。I need to parse complex expresion from string to bool.它只能包含:*布尔值(真/假)*括号中,* AND / OR操作数(安培;&安培;,||)It can only contain:* bo...
我需要解析复杂的EX presion公司从字符串为BOOL。
I need to parse complex expresion from string to bool.
它只能包含: *布尔值(真/假) *括号中, * AND / OR操作数(安培;&安培;,||)
It can only contain: * boolean values (true/false), * parenthesis, * AND/OR operands (&&, ||)
例如:
bool.Parse("((true || false) && (false || false)) || (true || false)"
不知道如何实现这一目标?
Any idea how to achieve this?
推荐答案
下面是一个狡猾的评估类,让你在C#code中的JScript.NET eval函数:
Here's a cunning evaluator class that gives you the JScript.NET Eval function within C# code:
static public class Evaluator
{
private const string _jscriptSource =
@"package Evaluator
{
class Evaluator
{
public function Eval(expr : String) : String
{
return eval(expr);
}
}
}";
static private object _evaluator;
static private Type _evaluatorType;
[SuppressMessage("Microsoft.Performance", "CA1810:InitializeReferenceTypeStaticFieldsInline",
Justification = "Can't be done inline - too complex")]
static Evaluator()
{
InstantiateInternalEvaluator();
}
static private void InstantiateInternalEvaluator()
{
JScriptCodeProvider compiler = new JScriptCodeProvider();
CompilerParameters parameters;
parameters = new CompilerParameters();
parameters.GenerateInMemory = true;
CompilerResults results;
results = compiler.CompileAssemblyFromSource(parameters, _jscriptSource);
Assembly assembly = results.CompiledAssembly;
_evaluatorType = assembly.GetType("Evaluator.Evaluator");
_evaluator = Activator.CreateInstance(_evaluatorType);
}
static public int EvaluateToInteger(string statement)
{
string s = EvaluateToString(statement);
return int.Parse(s);
}
static public double EvaluateToDouble(string statement)
{
string s = EvaluateToString(statement);
return double.Parse(s);
}
static public decimal ForceEvaluateToDecimal(string statement)
{
decimal result;
bool s = Decimal.TryParse(statement, out result);
return result;
}
static public decimal EvaluateToDecimal(string statement)
{
string s = EvaluateToString(statement);
return decimal.Parse(s);
}
static public string EvaluateToString(string statement)
{
object o = EvaluateToObject(statement);
return o.ToString();
}
static public bool EvaluateToBool(string statement)
{
object o = EvaluateToObject(statement);
return (bool)o;
}
static public object EvaluateToObject(string statement)
{
try
{
return _evaluatorType.InvokeMember(
"Eval",
BindingFlags.InvokeMethod,
null,
_evaluator,
new object[] {statement}
);
}
catch (Exception)
{
InstantiateInternalEvaluator();
return null;
}
}
}
您只需再调用Evaluator.EvaluateToBool(串)。从现有项目解除,所以你可能需要调整!
You just then call Evaluator.EvaluateToBool(string). Lifted from an existing project, so you may want to tweak!
相关推荐
最新文章