如何從Eval調用返回JSON字符串到JScript.NET？

Question

我正在嘗試使用JScript.NET來進行動態代碼評估。我有一個處理一個簡單的JScript.NET eval方法：

public static object Eval(string javascript) { 
    return Microsoft.JScript.Eval.JScriptEvaluate(javascript, Microsoft.JScript.Vsa.VsaEngine.CreateEngine()); 
} 

我希望能夠物體傳遞到評估和出他們弄回來了，我想通過JSON來做到這一點。我可以通過使用JSON.NET對它們進行序列化，將C＃中的對象傳入我的JScript中，而不會有任何問題。我遇到的麻煩是將JSON從我的JavaScript程序中取出出到我的C＃調用方。當我返回一個對象時，我得到的是一個JSObject（http://msdn.microsoft.com/en-us/library/microsoft.jscript.jsobject.aspx）。我顯然不能在JScript.NET中使用JSON.stringify（），因爲它不知道關於JSON的任何信息。或者，如果我可以將它序列化爲C＃中的JSON，但我可以接受腳本返回的JSObject，但JSON.NET不處理這些JSObject。

下面是一個代碼示例：

// using Newtonsoft.Json; // somewhere at the top 
dynamic json = new JObject(); 
json.Id = 1; 
json.Name = new JObject(); 
json.Name.First = "John"; 
json.Name.Last = "Doe"; 
json.Dob = new DateTime(1970, 2, 3); 

// dynamically construct a script for eval... could be anything... contrived example below. 
var js = new StringBuilder(); 

// set up a new object, passed from C# world into JScript.NET 
js.AppendLine("var person = " + json.ToString() + ";"); 

// do something useful 
js.AppendLine("person.FullName = person.Name.First + ' ' + person.Name.Last;"); 

// return person object... this comes back as JSObject. Wish I could JSON.stringify! 
js.AppendLine("person;"); 

// objResult is a JSObject, but how do I get json string??? 
dynamic objResult = JSEvaluator.Eval(js.ToString()); 

// tried JSON.NET, but it doesn't work! 
// var jsonResult = Newtonsoft.Json.JsonConvert.SerializeObject(objResult); 

任何幫助將不勝感激！

Answer 1

這是你在找什麼？本質上，我只是將json2.min.js（在@Michael B的建議中的註釋中）並將其作爲第一個業務訂單添加到javascript中。這使您可以根據需要對對象進行串聯處理，並將JSON字符串發送回C＃世界。從那裏你可以將它轉換回JObject並從中獲取數據或進一步操作它。根據您的示例代碼一個完整的程序如下：

using Newtonsoft.Json; 
using Newtonsoft.Json.Linq; 

class Program 
{ 
    static void Main(string[] args) 
    { 
     dynamic json = new JObject(); 
     json.Id = 1; 
     json.Name = new JObject(); 
     json.Name.First = "John"; 
     json.Name.Last = "Doe"; 
     json.Dob = new DateTime(1970, 2, 3); 

     // dynamically construct a script for eval... could be anything... contrived example below. 
     var js = new StringBuilder(); 

     // Add JSON2.min.js so we can stringify 
     js.AppendLine(@"var JSON;JSON||(JSON={}),(function(){""use strict"";function i(n){return n<10?""0""+n:n}function f(n){return o.lastIndex=0,o.test(n)?'""'+n.replace(o,function(n){var t=s[n];return typeof t==""string""?t:""\\u""+(""0000""+n.charCodeAt(0).toString(16)).slice(-4)})+'""':'""'+n+'""'}function r(i,e){var h,l,c,a,v=n,s,o=e[i];o&&typeof o==""object""&&typeof o.toJSON==""function""&&(o=o.toJSON(i)),typeof t==""function""&&(o=t.call(e,i,o));switch(typeof o){case""string"":return f(o);case""number"":return isFinite(o)?String(o):""null"";case""boolean"":case""null"":return String(o);case""object"":if(!o)return""null"";n+=u,s=[];if(Object.prototype.toString.apply(o)===""[object Array]""){for(a=o.length,h=0;h<a;h+=1)s[h]=r(h,o)||""null"";return c=s.length===0?""[]"":n?""[\n""+n+s.join("",\n""+n)+""\n""+v+""]"":""[""+s.join("","")+""]"",n=v,c}if(t&&typeof t==""object"")for(a=t.length,h=0;h<a;h+=1)typeof t[h]==""string""&&(l=t[h],c=r(l,o),c&&s.push(f(l)+(n?"": "":"":"")+c));else for(l in o)Object.prototype.hasOwnProperty.call(o,l)&&(c=r(l,o),c&&s.push(f(l)+(n?"": "":"":"")+c));return c=s.length===0?""{}"":n?""{\n""+n+s.join("",\n""+n)+""\n""+v+""}"":""{""+s.join("","")+""}"",n=v,c}}typeof Date.prototype.toJSON!=""function""&&(Date.prototype.toJSON=function(){return isFinite(this.valueOf())?this.getUTCFullYear()+""-""+i(this.getUTCMonth()+1)+""-""+i(this.getUTCDate())+""T""+i(this.getUTCHours())+"":""+i(this.getUTCMinutes())+"":""+i(this.getUTCSeconds())+""Z"":null},String.prototype.toJSON=Number.prototype.toJSON=Boolean.prototype.toJSON=function(){return this.valueOf()});var e=/[\u0000\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g,o=/[\\\""\x00-\x1f\x7f-\x9f\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g,n,u,s={""\b"":""\\b"",""\t"":""\\t"",""\n"":""\\n"",""\f"":""\\f"",""\r"":""\\r"",'""':'\\""',""\\"":""\\\\""},t;typeof JSON.stringify!=""function""&&(JSON.stringify=function(i,f,e){var o;n="""",u="""";if(typeof e==""number"")for(o=0;o<e;o+=1)u+="" "";else typeof e==""string""&&(u=e);t=f;if(f&&typeof f!=""function""&&(typeof f!=""object""||typeof f.length!=""number""))throw new Error(""JSON.stringify"");return r("""",{"""":i})}),typeof JSON.parse!=""function""&&(JSON.parse=function(n,t){function r(n,i){var f,e,u=n[i];if(u&&typeof u==""object"")for(f in u)Object.prototype.hasOwnProperty.call(u,f)&&(e=r(u,f),e!==undefined?u[f]=e:delete u[f]);return t.call(n,i,u)}var i;n=String(n),e.lastIndex=0,e.test(n)&&(n=n.replace(e,function(n){return""\\u""+(""0000""+n.charCodeAt(0).toString(16)).slice(-4)}));if(/^[\],:{}\s]*$/.test(n.replace(/\\(?:[""\\\/bfnrt]|u[0-9a-fA-F]{4})/g,""@"").replace(/""[^""\\\n\r]*""|true|false|null|-?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?/g,""]"").replace(/(?:^|:|,)(?:\s*\[)+/g,"""")))return i=eval(""(""+n+"")""),typeof t==""function""?r({"""":i},""""):i;throw new SyntaxError(""JSON.parse"");})})()"); 

     // set up a new object, passed from C# world into JScript.NET 
     js.AppendLine("var person = " + json.ToString() + ";"); 

     // do something useful 
     js.AppendLine("person.FullName = person.Name.First + ' ' + person.Name.Last;"); 

     // return stringified person object 
     js.AppendLine("JSON.stringify(person);"); 

     // objResult is a JScript.ConcatString 
     dynamic objResult = Eval(js.ToString()); 

     // Get our manipulated object back to the C# world 
     json = JsonConvert.DeserializeObject(objResult.ToString()); 

     // Print out the Full Name which was added inside the JS 
     Console.WriteLine(json.FullName); 
    } 

    public static object Eval(string javascript) 
    { 
     return Microsoft.JScript.Eval.JScriptEvaluate(javascript, Microsoft.JScript.Vsa.VsaEngine.CreateEngine()); 
    } 
} 

輸出：

John Doe