How to automate add my c# application issues to Github programmatically

You can use the GitHub API for that. Create a webhook and add an issue the following way:

POST /repos/:owner/:repo/issues

Example from https://developer.github.com/v3/issues/

{
  "title": "Found a bug",
  "body": "I'm having a problem with this.",
  "assignee": "octocat",
  "milestone": 1,
  "labels": [
    "Label1",
    "Label2"
  ]
}

So all you have to do is a HTTP - POST command to add an issue.

You can do a post request using a WebRequest.

Complete description for the api: https://api.github.com/repos/octocat/Hello-World/issues/1347

Complete C#-Example:

public void CreateBug(Exception ex) {
  WebRequest request = WebRequest.Create ("https://api.github.com/repos/yourUserName/YourRepo/issues ");
  request.Method = "POST";
  string postData = "{'title':'exception occured!', 'body':'{0}','assignee': 'yourUserName'}";
  byte[] byteArray = Encoding.UTF8.GetBytes (string.Format(postData,ex));
  request.ContentLength = byteArray.Length;
  Stream dataStream = request.GetRequestStream ();
  dataStream.Write (byteArray, 0, byteArray.Length);
  dataStream.Close ();
  WebResponse response = request.GetResponse ();
}

Now your issue has been created and response contains the response from GitHub

This is the "fast, easy" solution. If you want do do more with GitHub issues, @VonC's answer might be the better one as it offers a more object-related solution

If you need to create issues on a GitHub repo programmatically with C#, you can refer to the C# project octokit/octokit.net which will use the GitHub API.

It can create issue:

var createIssue = new NewIssue("this thing doesn't work");
var issue = await _issuesClient.Create("octokit", "octokit.net", createIssue);

Create returns a Task<Issue> which represents the created issue.