空值后继续在API中循环

Question

我试图通过调用API来获取课程列表和它们的版本号。 为了做到这一点，我必须循环并获得每个课程的ID，然后为每个课程ID，我必须循环并获得版本号。 然后对于每个课程ID，我必须循环获取版本号。 许多课程没有版本号，这就会返回。 "Message". "Version with specified id was not found: "没有找到指定ID的版本" 因为我的代码期望的是一个数组，所以它抛出了错误'Cannot deserialize the current JSON object (e.g. {"name": "value"}) into type 'System.Collections.Generic.List`1[getCourseVersions+Class2]'，因为该类型需要一个JSON数组（例如[1,2,3]）才能正确反序列。"

我的问题是这样的。 在遇到 "没有找到指定ID的版本 "的消息后 我如何强制它继续循环浏览所有课程？

下面是我的代码。

 public class Rootobject
{
    public Class1[] Property1 { get; set; }
}

public class Class1
{
    public string CourseType { get; set; }
    public string Id { get; set; }
    public string Name { get; set; }
    public object Description { get; set; }
    public object Notes { get; set; }
    public object ExternalId { get; set; }
    public object AccessDate { get; set; }
    public int? ExpireType { get; set; }
    public Expireduration ExpireDuration { get; set; }
    public object ExpiryDate { get; set; }
    public int? ActiveStatus { get; set; }
    public string[] TagIds { get; set; }
    public object[] ResourceIds { get; set; }
    public object[] EditorIds { get; set; }
    public object[] Prices { get; set; }
    public object[] CompetencyDefinitionIds { get; set; }
    public object[] PrerequisiteCourseIds { get; set; }
    public object[] PostEnrollmentCourseIds { get; set; }
    public bool? AllowCourseEvaluation { get; set; }
    public string CategoryId { get; set; }
    public string CertificateUrl { get; set; }
    public object Audience { get; set; }
    public object Goals { get; set; }
    public object Vendor { get; set; }
    public object CompanyCost { get; set; }
    public object LearnerCost { get; set; }
    public object CompanyTime { get; set; }
    public object LearnerTime { get; set; }
}

public class Expireduration
{
    public int? Years { get; set; }
    public int? Months { get; set; }
    public int? Days { get; set; }
    public int? Hours { get; set; }
}


public class Versions
{
    public Class1[] Property1 { get; set; }
}

public class Class2
{
    public string Id { get; set; }
    public string CourseId { get; set; }
    public string CourseName { get; set; }
    public string VersionNumber { get; set; }
    public string Notes { get; set; }
    public DateTime? DateAdded { get; set; }
}

//get authorization token from Absorb
private static string GenerateToken()
{
    //do stuff to get authorization token
    return token;
}

protected void Page_Load(object sender, EventArgs e)
{
    //get the generated token
    var strToken = GenerateToken();

    //build API call to get curricula data
    ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12 | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls;

    var courseClient = new RestClient($"https://urlgoeshere/");
    var courseRequest = new RestRequest("mycourses", Method.GET);
    courseClient.Timeout = 5000;
    courseRequest.AddHeader("Authorization", strToken);
    courseRequest.AddHeader("Content-Type", "application/json");

    var courseResponse = courseClient.Execute(courseRequest);
    var courseContent = courseResponse.Content;

    var Curriculum = JsonConvert.DeserializeObject<List<Class1>>(courseContent);

    //build API call to get enrooment data for each curriculum
    var enrollmentClient = new RestClient($"https://urlgoeshere/");
    enrollmentClient.Timeout = 5000;

    //loop through each curriculum and get version for each
    foreach (var ro in Curriculum)
    {
        var versionRequest = new RestRequest("courseversions/" + ro.Id, Method.GET);
        versionRequest.AddHeader("Authorization", strToken);
        versionRequest.AddHeader("Content-Type", "application/json");

        var versionResponse = enrollmentClient.Execute(versionRequest);
        var versionContent = versionResponse.Content;

        //this is where it throws the error
        var versionData = JsonConvert.DeserializeObject<List<Class2>>(versionContent);
        //loop through courses and get versioning information
        foreach (var course in versionData)
        {
            var id = course.Id;
            var courseID = course.CourseId;
            var courseName = course.CourseName;
            var versionNumber = course.VersionNumber;
            var notes = course.Notes;
            var dateAdded = course.DateAdded;

           //display data on page.

            Response.Write("ID: " + id + "<br />");
            Response.Write("CourseID: " + courseID + "<br />");
            Response.Write("Course Name: " + courseName + "<br />");
            Response.Write("Version: " + versionNumber + "<br />");
            Response.Write("Notes: " + notes + "<br />");
            Response.Write("Date Added: " + dateAdded + "<br />");
        }
}
}

}

Answer 1

你在这里有几个选择。

1）检查一些额外的属性在 versionResponse 值，然后再尝试在下一行进行反序列化。RestSharp在响应上提供了一些属性，这些属性除了可以设置内容外，还可以帮助告诉你请求失败了，你可以在ifelse块中使用这些属性来跳过你知道不会工作的行为。

你可以检查响应状态，找出是否有任何错误。 以下属性可以告诉你这些错误。

• IsSuccessful
• 响应状态
• 状态码
• 错误信息
• 错误异常

可能是请求被执行了，你得到了200个OK状态码和一些内容，但输入的Data属性是空的。

http:/restsharp.orgget-helpfaq.html#empty-response。

2) RestSharp还可以使用 Execute<T> 方法，它将以强类型的方式返回对象。然后你可以自定义RestSharp在反序列化失败的情况下的行为，通过指示它使用 FailOnDeserialization, ThrowOnDeserialization或 ThrowOnAnyError 与相应的属性。

https:/github.comrestsharpRestSharpwikiRecommended-Usage。http:/restsharp.orgusageexceptions.html。