如何使用带有 WebClient 的令牌来授权 Azure Web API？

Question

我已经寻找了在 WebClient 中使用令牌的任何示例，但没有找到一个有效的示例。 我正在将 Authorization 标头设置为令牌。 下面是我尝试的最后一个示例，但我总是收到 401 Unauthorized 异常。 该令牌来自 Microsoft Graph/MASAL，我正在尝试访问 Azure Web API。

这是检索令牌的位置：

    /// <summary>
    /// Call AcquireToken - to acquire a token requiring user to sign-in
    /// </summary>
    private async void CallGraphButton_Click(object sender, RoutedEventArgs e)  
    {
        AuthenticationResult authResult = null;
        var app = App.PublicClientApp;
        ResultText.Text = string.Empty;
        TokenInfoText.Text = string.Empty;

        var accounts = await app.GetAccountsAsync();
        var firstAccount = accounts.FirstOrDefault();

        try
        {
            authResult = await app.AcquireTokenSilent(scopes, firstAccount)
                .ExecuteAsync();
        }
        catch (MsalUiRequiredException ex)
        {
            // A MsalUiRequiredException happened on AcquireTokenSilent.
            // This indicates you need to call AcquireTokenInteractive to acquire a token
            System.Diagnostics.Debug.WriteLine($"MsalUiRequiredException: {ex.Message}");

            try
            {
                authResult = await app.AcquireTokenInteractive(scopes)
                    .WithAccount(accounts.FirstOrDefault())
                    .WithPrompt(Prompt.SelectAccount)
                    .ExecuteAsync();
            }
            catch (MsalException msalex)
            {
                ResultText.Text = $"Error Acquiring Token:{System.Environment.NewLine}{msalex}";
            }
        }
        catch (Exception ex)
        {
            ResultText.Text = $"Error Acquiring Token Silently:{System.Environment.NewLine}{ex}";
            return;
        }

        if (authResult != null)
        {
            ResultText.Text = await GetHttpContentWithToken(graphAPIEndpoint, authResult.AccessToken);
            DisplayBasicTokenInfo(authResult);
            this.SignOutButton.Visibility = Visibility.Visible;
            
            Get(authResult.AccessToken); //Call "Get" to test the token
        }
    }

这是使用令牌的地方：

    public List<WeatherForecast> Get(string Username,string Token)
    {
        try
        {
            using (WebClient webClient = new WebClient())
            {
                webClient.Headers.Add("Authorization", "Bearer "+Token);
                webClient.BaseAddress = StaticItems.EndPoint;
                webClient.Credentials = CredentialCache.DefaultCredentials;
                var json = webClient.DownloadString("");
                var list = JsonConvert.DeserializeObject<List<WeatherForecast>>(json);
                return list;
            }
        }
        catch (WebException ex)
        {
            throw ex;
        }
    }
}