Javascript TypeError：JSON數組對象未定義

我從服務器響應中獲取完美創建的JSON對象。Javascript TypeError：JSON數組對象未定義

例如：

{ 
    "users": [ 
     { 
      "userId": 20410, 
      "firstName": "Viral", 
      "lastName": "Shah", 
      "loginId": "[email protected]", 
      "userRole": 3 
     }, 
     { 
      "userId": 400881, 
      "firstName": "Viral", 
      "lastName": "Shah", 
      "loginId": "[email protected]", 
      "userRole": 0 
     }, 
     { 
      "userId": 425622, 
      "firstName": "Viral", 
      "lastName": "Shah", 
      "loginId": "[email protected]", 
      "userRole": 0 
     } 
    ] 
}

我使用AJAX象下面這樣在JavaScript中使用此：

var jsonobj2 = null; 
var respObj = getSearchedWPUsers(firstname, lastname, loginid); //return json response 
var len = respObj.length; 
jsonobj2 = eval('(' + respObj + ')'); 


var tablehtml = "<table><tr><td><b>First Name</td><td><b>Last Name</td><td><b>Login Id</td><td><b>Editing Rights</td></tr><tr></tr>"; 

for (i = 0; i < len; i++) { 
    tablehtml = tablehtml + "<tr>"; 
    //-------------- 
    tablehtml = tablehtml + "<td>"; 
    tablehtml = tablehtml + jsonobj2.users[i].firstName; 
    tablehtml = tablehtml + "</td>"; 
    //-------------- 
    tablehtml = tablehtml + "<td>"; 
    tablehtml = tablehtml + jsonobj2.users[i].lastName; 
    tablehtml = tablehtml + "</td>"; 
    //-------------- 
    tablehtml = tablehtml + "<td>"; 
    tablehtml = tablehtml + jsonobj2.users[i].loginId; 
    tablehtml = tablehtml + "</td>"; 
    //-------------- 
    tablehtml = tablehtml + "<td><b>"; 
    var role = jsonobj2.users[i].userRole; 
    if (role == 1 || role == 2 || role == 3) tablehtml = tablehtml + "<a href ='javascript:removeXML(" + jsonobj2.users[i].userId + ")'><u><font color='red'>Revoke access</font></a> "; 
    else tablehtml = tablehtml + "<a href ='javascript:generateXML(" + jsonobj2.users[i].userId + ")'><u><font color='blue'>Assign access</font></a> "; 

    tablehtml = tablehtml + "</td>"; 
    tablehtml = tablehtml + "</tr>"; 

} 
tablehtml = tablehtml + "</table>"; 


document.getElementById("TableHolder").innerHTML = tablehtml; 

//--------------------------

它拋出錯誤像下面

TypeError: jsonobj2.users[i] is undefined
[Break On This Error]
tablehtml = tablehtml + jsonobj2.users[i].firstName;

與JSON.parse(serverresponse);嘗試 - 沒什麼發生了

請幫助

來源

2013-01-11 Sam

你確定'respObj'是你認爲它是什麼嗎？從返回Ajax調用的函數返回值似乎很奇怪。請告訴我們它包含的內容。 –

你確定'respObj'包含了什麼嗎？您可能需要執行'async：false' ajax以便從ajax調用中返回某些內容。因爲ajax是異步的。 –

你是否檢查過螢火蟲中的respObj？檢查螢火蟲響應。 – Learner

試試這個：

jsonobj2 = eval('(' + respObj + ')'); 
var len = jsonobj2.users.length;

據我瞭解，respObj是包含JSON響應的字符串，但它仍然需要被解析。所以，如果你做respObj.length，你會得到正確的字符串的長度，但不是用戶數組的長度。另外，我建議你使用JSON.parse（只要通過瀏覽器中提供）來分析，而不是使用eval這樣的響應：

var respObj = getSearchedWPUsers(firstname, lastname, loginid); 
var jsonobj2 = JSON.parse ? JSON.parse(respObj) : eval('(' + respObj + ')'); 
var len = respObj && respObj.users ? respObj.users.length : 0;

然而，隨着菲利克斯克林和阿米爾阿德南說，Ajax調用大多是異步的，所以你可能會通過一個回調函數作爲參數，它將按照你的意願處理響應：

getSearchedWPUsers(firstname, lastname, loginid, function(respObj){ 
    var jsonobj2 = JSON.parse ? JSON.parse(respObj) : eval('(' + respObj + ')'); 
    var len = respObj && respObj.users ? respObj.users.length : 0; 
    var tablehtml = "<table><tr><td><b>First Name</td><td><b>Last Name</td><td><b>Login Id</td><td><b>Editing Rights</td></tr><tr></tr>"; 

    for (i = 0; i < len; i++) { 
     tablehtml = tablehtml + "<tr>"; 
     //-------------- 
     tablehtml = tablehtml + "<td>"; 
     tablehtml = tablehtml + jsonobj2.users[i].firstName; 
     tablehtml = tablehtml + "</td>"; 
     //-------------- 
     tablehtml = tablehtml + "<td>"; 
     tablehtml = tablehtml + jsonobj2.users[i].lastName; 
     tablehtml = tablehtml + "</td>"; 
     //-------------- 
     tablehtml = tablehtml + "<td>"; 
     tablehtml = tablehtml + jsonobj2.users[i].loginId; 
     tablehtml = tablehtml + "</td>"; 
     //-------------- 
     tablehtml = tablehtml + "<td><b>"; 
     var role = jsonobj2.users[i].userRole; 
     if (role == 1 || role == 2 || role == 3) 
      tablehtml = tablehtml + "<a href ='javascript:removeXML(" + jsonobj2.users[i].userId + ")'><u><font color='red'>Revoke access</font></a> "; 

     else tablehtml = tablehtml + "<a href ='javascript:generateXML(" + jsonobj2.users[i].userId + ")'><u><font color='blue'>Assign access</font></a> "; 

     tablehtml = tablehtml + "</td>"; 
     tablehtml = tablehtml + "</tr>"; 

    } 
    tablehtml = tablehtml + "</table>"; 

    document.getElementById("TableHolder").innerHTML = tablehtml; 
});

來源

2013-01-11 14:41:59

它的工作。瞭解長度的錯誤。非常感謝Mark – Sam

Javascript TypeError：JSON數組對象未定義

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