Removing object using JArrayItem.Remove("value") not working-CodePudding

I am trying to remove an object from an existing JArray, but when I run the method to delete the property from the JArray, the property still exists.

I tried simply using the code below

JObject rss1 = JObject.Parse(File.ReadAllText("online.json"));
JObject uList = (JObject)rss1["uList"];
JArray newOnline = (JArray)uList["online"];
newOnline.Remove("value");

The code above is almost directly copied and pasted from the Newtonsoft.Json documentation on modifying Json, but only changed to remove the new item instead of adding it. I've tried other post's solutions, but none of them work. Adding the field works as expected, but trying to remove it does not work whatsoever.

Below is the JSON file's contents

{
  "uList": {
    "placeHolder": "placeHolderValue",
    "online": [
      "value"
    ]
  }
}

Below is the expected JSON output of the code being ran

{
  "uList": {
    "placeHolder": "placeHolderValue",
    "online": [
    ]
  }
}

And, below, is the actual output of the code being ran

{
  "uList": {
    "placeHolder": "placeHolderValue",
    "online": [
      "value"
    ]
  }
}

Am I doing something wrong and not realizing it?

CodePudding user response：

The problem you've got is that you don't actually have a string in your array, you have a JValue. The JArray.Remove method accepts a JToken, but the JToken produced by implicitly casing your string to a JValue is not equal to the one being removed.

There's one of two solutions that come to mind:

Find the item in the array and then pass that to the remove method:

JToken item = newOnline.FirstOrDefault(arr => arr.Type == JTokenType.String && arr.Value<string>() == "value");
newOnline.Remove(item);

Use the .Remove method of the array item to remove it from the array:

JToken item = newOnline.FirstOrDefault(arr => arr.Type == JTokenType.String && arr.Value<string>() == "value");
item?.Remove();

CodePudding user response：

You can also remove JToken by querying value string present in online JArray.

Parse string to JObject:

JObject rss1 = JObject.Parse(File.ReadAllText("online.json"));

Now remove particular token using below query.

rss1.SelectTokens("$.uList.online[?(@ == 'value')]").FirstOrDefault()?.Remove();

Try online