Web Api Not recognizing RestClient framework

Question

I am trying to do a test post to a 3rd party web api. The code how to post was provided by the documentation from 3rd party.

'RestClient' is a namespace but is used like a type
The type or namespace name 'RestRequest' could not be found (are you missing a using directive or an assembly reference?)
The type or namespace name 'IRestResponse' could not be found (are you missing a using directive or an assembly reference?)
The name 'ParameterType' does not exist in the current context
The name 'Method' does not exist in the current context

The method I am working with:

public void CreatePanelists (Newtonsoft.Json.Linq.JObject data)
{

    Parameters parameters = JsonConvert.DeserializeObject<Parameters>(data.ToString())
    IList<Panelist> panelistList = parameters.panelists;
    string id = parameters.id;

    var client = new RestClient("https://3rdparty.com/v2/events/5893/atendees");
    var request = new RestRequest(Method.POST);
    request.AddHeader("content-type", "application/json");
    request.AddHeader("authorization", "Bearer vJRMZ92lsOE1sKGVF7_4zCezTjxO2RoFeOVGULSJS2_dRhgU5QfZeKqGaoS0ogPv0WISEuZ1RcNzJDUsv27uGA");
    request.AddParameter("application/json", "{\"attendees\":[{\"name\":\"Mary\",\"email\":\"[email protected]\"},{\"name\":\"Mike\",\"email\":\"[email protected]\"}]}", ParameterType.RequestBody);
    IRestResponse response = client.Execute(request);
}

I installed RestClient 4.0.0 but that did not remove the errors.

I am not using .Net not .net Core. What am I missing?

First time developing this type of project, please pardon if my technical language is not correct.

Your help is much appreciated.

Thank you, Erasmo

UPDATE - I was able to install RestSharp Version 106.11.4.0, and RestClient Version 2.5.0.6.

The only error that persists is

'RestClient' is a namespace but is used like a type

Solution

It seems like you missed to include namespace for the use of RestClient package. use the following namespace at top of the file.

using RestSharp;

Also, you should install nuget package before use this RestClient package. If not installed , then use follow command in Nuget package manager console.

PM> install-package RestSharp

Comments

[erasmo carlos]

I am unable to install RestSharp. I updated my question with the reason.

[Prerak Acharya]

You are able to installed Restsharp ? In question description you mentioned that "I installed RestClient 4.0.0 but that did not remove the errors."

[erasmo carlos]

I updated my question. RestSharp and RestClient are installed. The only error that parsists: 'RestClient' is a namespace but is used like a type