これは私の HttpService クラスです。正常に動作します。しかし、奇妙に思えます。すべての関数のコードはほとんど同じです。そして、すべての関数、特に TaskCanceledException に try/catch を記述する必要があります。ここでキャッチしないと、アプリケーションが終了します。コードを最適化する方法の例を教えてもらえますか?
[Export(typeof(IDataSource))]
public class HttpService : IDataSource
{
    HttpClient client = new HttpClient();
    public HttpService()
    {
        client.BaseAddress = new Uri("https://localhost:3721");
        client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
    }
    public void Initialize(CurrentUser currentUser)
    {
        client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic",
            Convert.ToBase64String(Encoding.UTF8.GetBytes(currentUser.Name + ":" + currentUser.Password)));
    }
    public async Task<IEnumerable<User>> getUsers()
    {
        try
        {
            var response = await client.GetAsync("api/User");
            //response.EnsureSuccessStatusCode(); // Throw on error code.
            if (response.IsSuccessStatusCode)
            {
                var result = await response.Content.ReadAsAsync<IEnumerable<User>>();
                return result;
            }
            else
            {
                return null;
            }
        }
        catch (Newtonsoft.Json.JsonException ex)
        {
            Console.WriteLine(ex.ToString());
        }
        catch (HttpRequestException ex)
        {
            Console.WriteLine(ex.ToString());
        }
        catch (TaskCanceledException ex)
        {
            Console.WriteLine(ex.ToString());
        }
        return null;
    }
    public async Task<IEnumerable<permission>> getPermission()
    {
        try
        {
            var response = await client.GetAsync("api/User");
            //response.EnsureSuccessStatusCode(); // Throw on error code.
            if (response.IsSuccessStatusCode)
            {
                var result = await response.Content.ReadAsAsync<IEnumerable<permission>>();
                return result;
            }
            else
            {
                return null;
            }
        }
        catch (Newtonsoft.Json.JsonException ex)
        {
            Console.WriteLine(ex.ToString());
        }
        catch (HttpRequestException ex)
        {
            Console.WriteLine(ex.ToString());
        }
        catch (TaskCanceledException ex)
        {
            Console.WriteLine(ex.ToString());
        }
        return null;
    }
    public async Task<CurrentUser> getCurrentUserInfo(User user)
    {
        try
        {
            var response = await client.GetAsync("api/User?name=" + user.Name);
            if (response.IsSuccessStatusCode)
            {
                var result = await response.Content.ReadAsAsync<CurrentUser>();
                return result;
            }
            else
            {
                return null;
            }
        }
        catch (Newtonsoft.Json.JsonException ex)
        {
            Console.WriteLine(ex.ToString());
        }
        catch (HttpRequestException ex)
        {
            Console.WriteLine(ex.ToString());
        }
        catch (TaskCanceledException ex)
        {
            Console.WriteLine(ex.ToString());
        }
        return null;
    }
}