The type or namespace name 'MediaTypeHeaderValue' could not be found-CodePudding

I created a C# project using

cd /tmp
dotnet new console -o mydotnetapp
cd mydotnetapp

then I replaced the code in Program.cs with code that sends a web request with a custom Content-Type header:

HttpClient client = new HttpClient();

HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, "http://localhost:8888/");

request.Headers.Add("Accept", "application/json");

request.Content = new StringContent("18233982904");
request.Content.Headers.ContentType = new MediaTypeHeaderValue("application/json");

HttpResponseMessage response = await client.SendAsync(request);
response.EnsureSuccessStatusCode();
string responseBody = await response.Content.ReadAsStringAsync();

and I ran it using dotnet run and I get this error:

/private/tmp/mydotnetapp/Program.cs(8,43): error CS0246: The type or namespace name 'MediaTypeHeaderValue' could not be found (are you missing a using directive or an assembly reference?) [/private/tmp/mydotnetapp/mydotnetapp.csproj]

The build failed. Fix the build errors and run again.

What am I doing wrong? This seems like an issue with me using an old version of the HTTP library, but my .csproj file says I'm using .NET 6

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net6.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>

</Project>

CodePudding user response：

it is part of System.Net.Http.Headers' namespace.

you need to add this.

using System.Net.Http.Headers;