Unexpected Character Encountered While Parsing Value

Unexpected character encountered while parsing value

Possibly you are not passing JSON to DeserializeObject.

It looks like from File.WriteAllText(tmpfile,... that type of tmpfile is string that contain path to a file. JsonConvert.DeserializeObject takes JSON value, not file path - so it fails trying to convert something like @"c:\temp\fooo" - which is clearly not JSON.

Unexpected character encountered while parsing value line 1, position 1

First, when you are using async methods you should add await keyword:

var response = await client.PostAsync(url, content);
return await response.Result.Content.ReadAsStringAsync();

Secondly, you are sending an array, so why not just try to send it and get as object not string:

var updateData = new ArrayList();
var jsonObject = JsonConvert.SerializeObject(updateData);
var content = new StringContent(jsonObject, Encoding.UTF8, "application/json");
var res = await apiClient.PutAsync(url, content);

And then in WebAPI:

[HttpPost]
public int HandleRequest([FromBody] ArrayList list)
{
    return 1;
}

Message = "Unexpected character encountered while parsing value: [. Path '', line 1, position 1."

You can parse your string to a strongly typed Model and then de-serialize to it OR you can use dynamic and access the properties as shown below:

You can find a working example here

using System;
using Newtonsoft.Json;
using System.Collections.Generic;
                    
public class Program
{
    public static void Main()
    {
        var myJsonString=@"[{'id':3,'name':'Sales'},{'id':4,'name':'PMO'},{'id':5,'name':'Research And Development'},{'id':6,'name':'Product Management'},{'id':7,'name':'HR'},{'id':8,'name':'Ava'},{'id':9,'name':'IT'}]";
        var result =JsonConvert.DeserializeObject<List<Root>>(myJsonString);
        Console.WriteLine("Example using Model: \n");
        foreach(var item in result)
        {
            Console.WriteLine(item.id);
            Console.WriteLine(item.name);           
        }
        
        Console.WriteLine("\n");
        Console.WriteLine("Example using Dynamic: \n");
        
        //Example using dynamic
        var resultDynamic=JsonConvert.DeserializeObject<dynamic>(myJsonString);
        foreach(var item in resultDynamic)
        {
            Console.WriteLine(item["id"]);
            Console.WriteLine(item["name"]);        
        }
    }
}

public class Root
{
    public int id { get; set; }
    public string name { get; set; }
}

Output:

Example using Model: 

3
Sales
4
PMO
5
Research And Development
6
Product Management
7
HR
8
Ava
9
IT


Example using Dynamic: 

3
Sales
4
PMO
5
Research And Development
6
Product Management
7
HR
8
Ava
9
IT

Unexpected character encountered while parsing value: . Path '', line 1, position 1

To hit that default endpoint in Postman add the following in the body

"foo"

To use the following

{
  "foo": "bar"
}

you would need a class like this

public class MyClass
{
  public string Foo { get; set; }
}

then change the Post to

// POST api/values
[HttpPost]
public void Post([FromBody] MyClass value)
{
}

Hope that helps

Unexpected character encountered while parsing value ASP.NET Core and Newtonsoft

this works for me

 Definition definition = Newtonsoft.Json.JsonConvert.DeserializeObject<Definition>(s);

classes

public partial class Definition
    {
        [JsonProperty("name")]
        public string Name { get; set; }

        [JsonProperty("id")]
        public long Id { get; set; }

        [JsonProperty("palette")]
        public Palette Palette { get; set; }
    }

    public partial class Palette
    {
        [JsonProperty("name")]
        public string Name { get; set; }

        [JsonProperty("default")]
        public bool Default { get; set; }

        [JsonProperty("swatch")]
        public Swatch Swatch { get; set; }
    }

    public partial class Swatch
    {
        [JsonProperty("colors")]
        public Dictionary<string,string> Colors { get; set; }
    }

C# Json.net Unexpected character encountered while parsing value:

So. \u001f means you received the byte 1F. ‹ is in the range of extended ASCII with encoding 8B. \b is the ASCII backspace character with encoding 08.

1F 8B is the magic number for GZIP (and the 08 is the compression method: DEFLATE).

So, the server's one of the broken ones which gives you back a gzip-compressed response, even though you didn't say you could accept gzip-compressed responses.

You can tell HttpClient to automatically decompress gzip-compressed responses:

HttpClientHandler handler = new HttpClientHandler()
{
    AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate
};
using var client = new HttpClient(handler));

var httpResponseMessage = await client.GetAsync(url);
// ...

Unexpected character encountered while parsing value: <. Path '', line 0, position 0.'

You're getting the JSON parsing exception because the server is returning a text response (which you've listed in your question).

Unknown web method addEditTickets. Parameter name: methodName

Based on the error, it seems that the URL you're trying to use is invalid. Verify that the URL you're constructing is valid; it appears that functionName does not contain the correct value in this expression:

System.Configuration.ConfigurationManager.AppSettings["links"].ToString() + functionName

ASP NET CORE with ANGULAR -"Unexpected character encountered while parsing value: a. Path '', line 0, position 0." / Error during a PUT Request

An HTTP PUT requires you to include an ID in the URI:

information/search-jobs-setbyusers/{id}

(See also https://restfulapi.net/rest-put-vs-post/)

So, you could try an HTTP POST.

The following is worth trying:

export class SearchJobsDto
{
    public SearchJob: string;
}

getCompaniesSearchedByUser(searchString: string) 
{
   let model: SearchJobsDto = { searchString: SearchJob }
   return this.http.post(this.baseUrl + "information/search-jobs-setbyusers/", model, this.httpOptions);
}

and the controller method as a POST:

[HttpPost("search-jobs-setbyusers")]
public async 
   Task<ActionResult<IEnumerable<GetCompaniesJobsLinksDto>>>SearchJobs(
      [FromBody]SearchJobsDto searchJobsDto)
{
   ...
}

The error is likely due to one or both of these:

1. Passing an Any type parameter for the model which would give the
   parsing error when resolving binding of the parameter type to the type of the model parameter in the API controller method. An explicit type for the parameter passed in the POST/PUT model is best practice.

2. Not including an ID for the HTTP PUT with the model payload parameter.

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