AcquireTokenSilentAsync无法对用户进行身份验证

只有当该用户已经有一个包含您请求的作用域的缓存令牌时,您才能以静默方式获取该令牌(它可以有更多,但至少需要有您所请求的)。

这就是为什么 AcquireTokenSilentAsync 应始终用Try/Catch块包装。如果找不到匹配的令牌,则需要启动交互式流。以下是 MSAL Wiki :

AuthenticationResult result = null;
try
{
    result = await app.AcquireTokenSilentAsync(scopes, app.Users.FirstOrDefault());
}
catch (MsalUiRequiredException ex)
{
    // A MsalUiRequiredException happened on AcquireTokenSilentAsync. 
    // This indicates you need to call AcquireTokenAsync to acquire a token
    System.Diagnostics.Debug.WriteLine($"MsalUiRequiredException: {ex.Message}");

    try
    {
        result = await app.AcquireTokenAsync(scopes);
    }
    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 (result != null)
{
    string accessToken = result.AccessToken;
    // Use the token
}