C# Converting string to JSON

Question

I am trying to POST to using C# to a JSON payload which I can achieve but I am having trouble understanding how to replace the sample string with my own string.

From the code below you can see I have a string I want to send to my weblink. The code runs fine when I use "{\"text\":\"Hello, World!\"}" for the StringContent but if I try to replace it with the string of output_message it doesn't work. I am trying to work out how I convert my output_message to a format that JSON can recognize.

 {
 string output_message = "The file " + filename + " has been modified by " + user_modified + " and moved to the " + file_state + " file state. Please review the " + filename + " file and approve or reject."; 
 PostWebHookAsync(output_message);
 Console.ReadLine();
 }
 static async void PostWebHookAsync(string Aoutput_message)
 {
 using (var httpClient = new HttpClient())
 {
 using (var request = new HttpRequestMessage(new HttpMethod("POST"), "www.mywebsitelink"))
 {
 //request.Content = new StringContent("{\"text\":\"Hello, World!\"}", Encoding.UTF8, "application/json"); // - original do not delete
 request.Content = new StringContent(Aoutput_message, Encoding.UTF8, "application/json");
 var response = await httpClient.SendAsync(request);
 Console.WriteLine(response.StatusCode);
 Console.WriteLine(response.Content);
 }
 }
 }

I want to replace "{\"text\":\"Hello, World!\"}" with a string

• vasily.sib: JSON is stand for JavaScript Object Notation, so it has some validation rules. In your case, you can send $"\{\"text\":\"{output_message}\"\}" or $"\{\"value\":\"{output_message}\"\}", or even $"[\"{output_message}\"]"
• user6911980: Possible duplicate of Convert JSON String To C# Object

Answer 1

To the best of my knowledge people are moving away from JavaScriptSerializer and towards Json.NET. It's even recommended in the documentation here

The corresponding Json.NET code would look something like:

static async void PostWebHookAsync(string output_message)
{
 using (var httpClient = new HttpClient())
 {
 using (var request = new HttpRequestMessage(new HttpMethod("POST"), "www.mywebsitelink"))
 {
 string jsonValue = JsonConvert.SerializeObject(new
 {
 text = output_message
 });
 request.Content = new StringContent(jsonValue, Encoding.UTF8, "application/json");
 var response = await httpClient.SendAsync(request);
 Console.WriteLine(response.StatusCode);
 Console.WriteLine(response.Content);
 }
 }
}

To use Json.NET you need to install the Newtonsoft.Json nuget package.

• AWH: This also work, thanks for your feedback. Whats the benefits of using this over the JavaScriptSerializer().Serialize function?
• Palle Due: @AWH: JavaScriptSerializer is not supported in .NET Core, so in order to make it "future-proof" you should use Json.NET. When deserializing I find Json.NET easier to work with, for serialization it's same-same.

Answer 2

The best way is to create an object and serialize it.

To use JavaScriptSerializer you have to add a reference to System.Web.Extensions.dll

So for your problem, we create an anonymous object with a property text we pass the value Aoutput_message

static async void PostWebHookAsync(string Aoutput_message)
{
 using (var httpClient = new HttpClient())
 {
 using (var request = new HttpRequestMessage(new HttpMethod("POST"), "www.mywebsitelink"))
 {
 //request.Content = new StringContent("{\"text\":\"Hello, World!\"}", Encoding.UTF8, "application/json"); // - original do not delete
 string jsonValue = new JavaScriptSerializer().Serialize(new
 {
 text = Aoutput_message,
 });
 request.Content = new StringContent(jsonValue, Encoding.UTF8, "application/json");
 var response = await httpClient.SendAsync(request);
 Console.WriteLine(response.StatusCode);
 Console.WriteLine(response.Content);
 }
 }
}

Examples