如何从 ExecuteScript 转换 json 数组

Question

范围

我想使用 Selenium 进行自动化 Web 测试并执行 JavaScript。字符串func1 包含我的js 函数，它被传递给ExecuteScript(func1)，它返回一个对象数组，看起来像{label:'start', time: 121}。

我想将ExecuteScript 的结果转换成List<timings>

var result = jsExecutor.ExecuteScript(func1); 
var list = (ReadOnlyCollection<object>)result;
var timings = (List<Timing>)list;

我收到了错误

 Cannot convert type 'System.Collections.ObjectModel.ReadOnlyCollection<object>' 
 to 'System.Collections.Generic.List<CoreConsoleApp.TestExecutions.Timing>' 

这是 func1

string func1= @"var t = window.performance.timing;
  var timings = [];
  timings.push({ label: 'navigationStart', time: t.navigationStart  });
  timings.push({ label: 'PageLoadTime', time: t.loadEventEnd - t.navigationStart  });

return timings;" // result is an array of js-objects

下面的代码是硒部分的sn-p

 public struct Timing
 {
   public string label;
   public int time;            
 }

 using (var driver = new FirefoxDriver())
 {
  ...
  var jsExecutor = (IJavaScriptExecutor)driver;
  var result = jsExecutor.ExecuteScript(func1); 
  var list = (ReadOnlyCollection<object>)result;
 }

问题

selenium 文档声明 ExecuteScript attempts to return a List 用于数组。 Func1 应该返回数组 {label: string, time: number} 它应该很容易将结果 var list = (ReadOnlyCollection<object>)result 转换为 List<string,int> timings = (List<timings>)list;

• 如何将“System.Collections.ObjectModel.ReadOnlyCollection”转换为 List？

更多信息

启动火狐var driver = new FirefoxDriver()打开一个URLdriver.Navigate().GoToUrl(url);找到某个按钮IWebElement button = driver.FindElement(By.Name("btnK"));提交表单button.Submit();提交后执行JavaScriptExecuteScript(func1)并将结果写入控制台

以上所有工作。但我无法将 JavaScript 转换为 c# 对象列表。

所以我的解决方法是这样的

var result = jsExecutor.ExecuteScript(func1); 
var list = (ReadOnlyCollection<object>)result;

foreach (object item in list)
{   
    var timing = (Dictionary<string, object>)item;
    foreach(KeyValuePair<string, object> kvp in timing)
    {
       Console.WriteLine("Key = {0}, Value = {1}", kvp.Key, kvp.Value);
    }                    
 }

这就出来了：

 Key = label, Value = navigationStart
 Key = time, Value = 1529720672670
 Key = label, Value = PageLoadTime
 Key = time, Value = 1194
 Key = label, Value = DOMContentLoadedTime
 Key = time, Value = 589
 Key = label, Value = ResponseTime

Answer 1

问题在于var result = jsExecutor.ExecuteScript(func1); 的结构与预期不同。

result 看起来类似于 List<object>() 我创建了这个 linqpad 程序：

var dictionary1= new Dictionary<string, object>();

dictionary1.Add("label", (object)"PageloadTime");
dictionary1.Add("time", (object)"1087");    
var dictionary2= new Dictionary<string, object>()
{ 
    {"label", (object)"DOMContentLoadedTime"},
    {"time", (object)"494"}
};

var list = new List<object>(); // this is the structure of result
list.Add(dictionary1);
list.Add(dictionary2);  
list.Dump();

如果你打电话给list.Dump();，它看起来像这样：

如您所见，该结构包含 n 个这种类型的字典 Dictionary<string, object>(); 因此我尝试了两个嵌套循环以更好地理解对象的嵌套

Object result = jsExecutor.ExecuteScript(func1); // 

var resultCollection = (ReadOnlyCollection<object>)result;       
foreach (Dictionary<string, object> item in resultCollection)
{
   Console.WriteLine("{0} ", item.GetType()); 
   foreach (KeyValuePair<string, object> kvp in item)
   {
     Console.WriteLine("Keys: {0} Values: {1}", kvp.Key, kvp.Value);
   }
}

最后

// create a structure similar to result
var list = new List<object>(); 
list.Add(dictionary1);
list.Add(dictionary2);  

var timings = new List<Timing>();

foreach (Dictionary<string, object> dict in list)
{       
    Console.WriteLine("Label = {0}  Value ={1} "
              , (string)dict["label"]
              , (string)dict["time"]);
    // create a timing object
    var t = new Timing();
    t.label = (string)dict["label"];
    t.time = (string)dict["time"];
    timings.Add(t);
}   

由于有时我得到(int)dict["time"] 的无效转换异常，我将属性时间从 int 更改为 string。

更新

正如 Steven Chong 建议的那样，我将函数 func1 更改为返回一个字符串：

public static string jsGetTiming(){

    // func1 is the javascript function that will get executed
    string func1= @"var t = window.performance.timing; 
    var PageLoadTime =  t.loadEventEnd - t.navigationStart;            
    var ResponseTime = t.responseEnd - t.requestStart;            

    var timings = 'navigationStart=' + t.navigationStart;
        timings += '|PageLoadTime=' + PageLoadTime;        
        timings += '|ResponseTime=' + ResponseTime;            
     return timings;";

   return func1;
} 

要将字符串func1作为函数执行，您可以这样调用它

 Object result = jsExecutor.ExecuteScript(MyClass.jsGetTiming());
 // result is a string and looks like this
result = 
 navigationStart=1534377023791|PageLoadTime=943  
   |DOMContentLoadedTime=434|ResponseTime=337
   |Response=269|DomainLookup=0
   |LoadEvent=5|UnloadEvent=8
   |DOMContentLoadedEvent=17 

Answer 2

在返回之前尝试序列化您的数据。

string func1= @"var t = window.performance.timing;
var timings = [];
timings.push({ label: 'navigationStart', time: t.navigationStart  });
timings.push({ label: 'PageLoadTime', time: t.loadEventEnd - t.navigationStart  });

return JSON.stringify(timings);" // result is string

并使用 Json.NET 在 c# 中访问您的数据

using Newtonsoft.Json.Linq;

string result = Convert.ToString(jsExecutor.ExecuteScript(func1));
Console.Write("result = " + result);
List<Timing> list = JToken.Parse(result).ToObject<List<Timing>>();
Console.Write("result = " + JToken.FromObject(list));

// or access using dynamic
dynamic dynamicList = JToken.Parse(jsExecutor.ExecuteScript(func1)); 
for (var i = 0; i < dynamicList.Count; i++) {
   Console.Write(dynamicList[i]);
}

Answer 3

您需要将result 反序列化为所需的List<Timings>。

1. 从here引用包JSON.Net

2. 反序列化result（假设是string）如下：

   List<Timing> timings = JsonConvert.DeserializeObject<List<Timing>>(result);

以下是关于序列化的一些基本帮助： https://www.newtonsoft.com/json/help/html/SerializingJSON.htm