如何最好地将类型类型的JArray转换为类型数组?

I've got a JArray that represents the json substring [1,2,3]. I'd like to turn it into an int[] instead.

我有一个表示json子串的JArray[1,2,3]。我想把它变成一个int[]。

What's the correct way of doing this? The best way I've found so far is to do the following:

正确的做法是什么?到目前为止我发现的最好的方法是:

int[] items = new int[myJArray.Count];

int i = 0;
foreach (int item in myJArray)
{
    items[i++] = item;
}

5 个解决方案

#1

int[] items = myJArray.Select(jv => (int)jv).ToArray();

#2

myJArray.ToObject<int[]>();

You can also specify HashSet, List etc.

您还可以指定HashSet、List等。

The accepted answer relies on .NET's conversion - this technique uses JSON.NET's own in addition to what .NET can provide so works with more scenarios.

被接受的答案依赖于。net的转换——该技术使用了JSON。NET本身除了。NET可以提供更多的场景。

#3

This is pretty weak because you have to convert back into a string, but if you are doing something quick and dirty, where the performance hit won't matter, I use the below method. I like it because I don't have to write any code to map properties between json/JObject and my POCO's.

这是非常弱的，因为您必须转换回字符串，但是如果您正在做一些快速和不干净的事情，在哪里性能受到影响并不重要，我使用下面的方法。我喜欢它，因为我不需要编写任何代码来映射json/JObject和POCO之间的属性。

public static class JsonExtensions {
    public static T As<T>(this JObject jobj) {
        return JsonConvert.DeserializeObject<T>(JsonConvert.SerializeObject(jobj));
    }

    public static List<T> ToList<T>(this JArray jarray) {
        return JsonConvert.DeserializeObject<List<T>>(JsonConvert.SerializeObject(jarray)); 
    }
}


    [Test]
    public void TestDeserializeRootObject() {
        var json = @"{ id: 1, name: ""Dwight"" }";
        var jfoo = JsonConvert.DeserializeObject(json);

        var foo = (jfoo as JObject).As<Foo>();
        Assert.AreEqual(1, foo.Id);
        Assert.AreEqual("Dwight", foo.Name);
    }

    [Test]
    public void TestDeserializeArray() {
        var json = @"[
            { id: 1, name: ""Dwight"" }
            , { id: 2, name: ""Pam"" }
        ]";

        var foosArr = JsonConvert.DeserializeObject(json);
        Assert.IsInstanceOf<JArray>(foosArr);
        Assert.AreEqual(2, (foosArr as JArray).Count);

        var foos = (foosArr as JArray).ToList<Foo>();
        Assert.AreEqual(2, foos.Count);
        var foosDict = foos.ToDictionary(f => f.Name, f => f);

        Assert.IsTrue(foosDict.ContainsKey("Dwight"));
        var dwight = foosDict["Dwight"];
        Assert.AreEqual(1, dwight.Id);
        Assert.AreEqual("Dwight", dwight.Name);

        Assert.IsTrue(foosDict.ContainsKey("Pam"));
        var pam = foosDict["Pam"];
        Assert.AreEqual(2, pam.Id);
        Assert.AreEqual("Pam", pam.Name);
    }

#4

A cast needed first for me:

我首先需要一个演员:

((Newtonsoft.Json.Linq.JArray)myJArray).Select(item => (int)item).ToArray()

#5

int[] items = new int[myJArray.Count];

for (int i=0; i < myJArray.Count;i++)
{
    items[i] = (int)myJArray[i]
}

this is the fastes solution you can do. The classic for is a bit faster than the ForEach as you access the item by the index(the foreach behind the scene uses the IEnumerator interface)

这是你能做的快速解决方案。当您通过索引访问项目时，经典的速度比ForEach要快一些(在场景后面的ForEach使用了IEnumerator接口)

or if you prefer:

或者如果你喜欢:

JsonArray arr = JsonConvert.Import("[1,2,3,4]");
int[] nums = (int[]) arr.ToArray(typeof(int));

#1

int[] items = myJArray.Select(jv => (int)jv).ToArray();

#2

myJArray.ToObject<int[]>();