Question

在这里回答我自己的问题我已经在Excel VBA中使用JSON做了一些工作，并发布了大量的发现，我将在Q＆amp;格式 https://stackoverflow.com/help/self-answer http://blog.stackoverflow.com/2011/07/its-ok-to-ask-and-answer-your-own-questions/

所以在stackoverflow的其他地方，人们可以看到有关在VBA中解析JSON的问题但他们似乎错过了一两招。

首先，我不再使用自定义JSON解析库，而是使用ScriptControl的Eval方法作为我所有JSON代码的基础。此外，我们还表达了对本机Microsoft解决方案的偏好。

以下是此问题构建的先前问题In Excel VBA on Windows, how to mitigate issue of dot syntax traversal of parsed JSON broken by IDE's capitalisation behaviour?。它显示了如何使用VBA.CallByName更健壮而不是使用点语法来遍历解析的JSON对象。另外一个先前的问题In Excel VBA on Windows, how to loop through a JSON array parsed?显示了它也可以如何用于访问数组元素。但是CallByName返回一个好奇的变量类型，它在Watch窗口中显示为Object / JScriptTypeInfo 如果在即时窗口中有一个类型的Debug.Print（或悬停在变量上），则会得到无信息的“[object Object]”。

我们如何改进并获得JSON字符串表示？

以下是您在Debug.Print（？）之后在立即窗口中看到的内容以及将鼠标悬停在变量上的屏幕截图。

这是5系列的问题3.这是完整的系列

Q1 In Excel VBA on Windows, how to mitigate issue of dot syntax traversal of parsed JSON broken by IDE's capitalisation behaviour?

Q2 In Excel VBA on Windows, how to loop through a JSON array parsed?

Q3 In Excel VBA on Windows, how to get stringified JSON respresentation instead of “[object Object]” for parsed JSON variables?

Q4 In Windows Excel VBA,how to get JSON keys to pre-empt “Run-time error '438': Object doesn't support this property or method”?

Q5 In Excel VBA on Windows, for parsed JSON variables what is this JScriptTypeInfo anyway?

Answer 1

与使用解析的JSON对象相关的其他堆栈溢出问题的答案使用迷你脚本方法，我们可以在这里使用此方法。

首先，我们承认Douglas Crockford是“Javascript：The Good Parts”（http://shop.oreilly.com/product/9780596517748.do）的作者并且是javascript专家。所以我们很乐意在字符串化方面采用他的代码。我们可以使用简单的Xml HTTP请求获取他的代码（通常缩写为XHR）并将返回结果传递给ScriptControl的AddCode方法。然后添加一些允许我们覆盖默认表示的代码通过调用Douglas的库来获取“[object Object]”。然后确保我们动态地将覆盖添加到我们所有的JScriptTypeInfo变量，我们用DecodeJsonString（）包装的ScriptControl的Eval方法以及我们用GetJSONObject（）包装的VBA.CallByName。

因此，

'Tools->References->
'Microsoft Script Control 1.0;  {0E59F1D2-1FBE-11D0-8FF2-00A0D10038BC}; C:\Windows\SysWOW64\msscript.ocx
'Microsoft Xml, v6.0

Option Explicit

Private Function GetScriptEngine() As ScriptControl
    Static soScriptEngine As ScriptControl
    If soScriptEngine Is Nothing Then
        Set soScriptEngine = New ScriptControl
        soScriptEngine.Language = "JScript"

        soScriptEngine.AddCode GetJavaScriptLibrary("https://raw.githubusercontent.com/douglascrockford/JSON-js/master/json2.js")
        soScriptEngine.AddCode "function overrideToString(jsonObj) { jsonObj.toString = function() { return JSON.stringify(this); } }"
    End If
    Set GetScriptEngine = soScriptEngine
End Function

Private Function GetJavaScriptLibrary(ByVal sURL As String) As String

    Dim xHTTPRequest As MSXML2.XMLHTTP60
    Set xHTTPRequest = New MSXML2.XMLHTTP60
    xHTTPRequest.Open "GET", sURL, False
    xHTTPRequest.send
    GetJavaScriptLibrary = xHTTPRequest.responseText

End Function

Private Function DecodeJsonString(ByVal JsonString As String) As Object
    Dim oScriptEngine As ScriptControl
    Set oScriptEngine = GetScriptEngine

    Set DecodeJsonString = oScriptEngine.Eval("(" + JsonString + ")")

    Call oScriptEngine.Run("overrideToString", DecodeJsonString) '* this gives JSON rendering instead of "[object Object]"

End Function

Private Function GetJSONObject(ByVal obj As Object, ByVal sKey As String) As Object
    Dim objReturn As Object
    Set objReturn = VBA.CallByName(obj, sKey, VbGet)
    Call GetScriptEngine.Run("overrideToString", objReturn) '* this gives JSON rendering instead of "[object Object]"
    Set GetJSONObject = objReturn
End Function

Private Sub TestJSONParsingWithCallByName2()

    Dim sJsonString As String
    sJsonString = "{'key1': 'value1'  ,'key2': { 'key3': 'value3' } }"


    Dim objJSON As Object
    Set objJSON = DecodeJsonString(sJsonString)

    Stop


    Dim objKey2 As Object
    Set objKey2 = GetJSONObject(objJSON, "key2")
    Debug.Print objKey2
    Stop

End Sub

以下是使用新代码的屏幕截图，其中显示了JScriptTypeInfo变量的字符串化

Answer 2

谢谢S Meaden，这就是我想要的，一种将JSON对象转换为字符串的简单方法。我使用了你的想法并将其与我的代码合并，但我不喜欢每次需要创建JSON对象时建立连接和下载脚本的想法。所以我将JSON2.js代码压缩成一个函数并使用它而不是我接下来粘贴它也许有人会喜欢这个想法。

Private Function JSON2() As String
    'https://stackoverflow.com/questions/37711073/in-excel-vba-on-windows-how-to-get-stringified-json-respresentation-instead-of
    'https://raw.githubusercontent.com/douglascrockford/JSON-js/master/json2.js
    JSON2 = _
        "if(typeof JSON!==""object""){JSON={};}" _
        & "(function(){""use strict"";var rx_one=/^[\],:{}\s]*$/;var rx_two=/\\(?:[""\\\/bfnrt]|u[0-9a-fA-F]{4})/g;var rx_three=/""[^""\\\n\r]*""|true|false|null|-?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?/g;var rx_four=/(?:^|:|,)(?:\s*\[)+/g;var rx_escapable=/[\\""\u0000-\u001f\u007f-\u009f\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g;var rx_dangerous=/[\u0000\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g;function f(n){return n<10?""0""+n:n;}" _
        & "function this_value(){return this.valueOf();}" _
        & "if(typeof Date.prototype.toJSON!==""function""){Date.prototype.toJSON=function(){return isFinite(this.valueOf())?this.getUTCFullYear()+""-""+" _
        & "f(this.getUTCMonth()+1)+""-""+" _
        & "f(this.getUTCDate())+""T""+" _
        & "f(this.getUTCHours())+"":""+" _
        & "f(this.getUTCMinutes())+"":""+" _
        & "f(this.getUTCSeconds())+""Z"":null;};Boolean.prototype.toJSON=this_value;Number.prototype.toJSON=this_value;String.prototype.toJSON=this_value;}" _
        & "var gap;var indent;var meta;var rep;function quote(string){rx_escapable.lastIndex=0;return rx_escapable.test(string)?""\""""+string.replace(rx_escapable,function(a){var c=meta[a];return typeof c===""string""?c:""\\u""+(""0000""+a.charCodeAt(0).toString(16)).slice(-4);})+""\"""":""\""""+string+""\"""";}" _
        & "function str(key,holder){var i;var k;var v;var length;var mind=gap;var partial;var value=holder[key];if(value&&typeof value===""object""&&typeof value.toJSON===""function""){value=value.toJSON(key);}" _
        & "if(typeof rep===""function""){value=rep.call(holder,key,value);}"
    JSON2 = JSON2 _
        & "switch(typeof value){case""string"":return quote(value);case""number"":return isFinite(value)?String(value):""null"";case""boolean"":case""null"":return String(value);case""object"":if(!value){return""null"";}" _
        & "gap+=indent;partial=[];if(Object.prototype.toString.apply(value)===""[object Array]""){length=value.length;for(i=0;i<length;i+=1){partial[i]=str(i,value)||""null"";}" _
        & "v=partial.length===0?""[]"":gap?""[\n""+gap+partial.join("",\n""+gap)+""\n""+mind+""]"":""[""+partial.join("","")+""]"";gap=mind;return v;}" _
        & "if(rep&&typeof rep===""object""){length=rep.length;for(i=0;i<length;i+=1){if(typeof rep[i]===""string""){k=rep[i];v=str(k,value);if(v){partial.push(quote(k)+(gap?"": "":"":"")+v);}}}}else{for(k in value){if(Object.prototype.hasOwnProperty.call(value,k)){v=str(k,value);if(v){partial.push(quote(k)+(gap?"": "":"":"")+v);}}}}" _
        & "v=partial.length===0?""{}"":gap?""{\n""+gap+partial.join("",\n""+gap)+""\n""+mind+""}"":""{""+partial.join("","")+""}"";gap=mind;return v;}}" _
        & "if(typeof JSON.stringify!==""function""){meta={""\b"":""\\b"",""\t"":""\\t"",""\n"":""\\n"",""\f"":""\\f"",""\r"":""\\r"",""\"""":""\\\"""",""\\"":""\\\\""};JSON.stringify=function(value,replacer,space){var i;gap="""";indent="""";if(typeof space===""number""){for(i=0;i<space;i+=1){indent+="" "";}}else if(typeof space===""string""){indent=space;}" _
        & "rep=replacer;if(replacer&&typeof replacer!==""function""&&(typeof replacer!==""object""||typeof replacer.length!==""number"")){throw new Error(""JSON.stringify"");}" _
        & "return str("""",{"""":value});};}" _
        & "if(typeof JSON.parse!==""function""){JSON.parse=function(text,reviver){var j;function walk(holder,key){var k;var v;var value=holder[key];if(value&&typeof value===""object""){for(k in value){if(Object.prototype.hasOwnProperty.call(value,k)){v=walk(value,k);if(v!==undefined){value[k]=v;}else{delete value[k];}}}}" _
        & "return reviver.call(holder,key,value);}" _
        & "text=String(text);rx_dangerous.lastIndex=0;if(rx_dangerous.test(text)){text=text.replace(rx_dangerous,function(a){return""\\u""+" _
        & "(""0000""+a.charCodeAt(0).toString(16)).slice(-4);});}" _
        & "if(rx_one.test(text.replace(rx_two,""@"").replace(rx_three,""]"").replace(rx_four,""""))){j=eval(""(""+text+"")"");return(typeof reviver===""function"")?walk({"""":j},""""):j;}" _
        & "throw new SyntaxError(""JSON.parse"");};}}());"
End Function

在Windows上的Excel VBA中，如何为已解析的JSON变量获取字符串化的JSON表示而不是“[object Object]”？

2 个答案: