从更大的 JSON 字符串中检索所需的字符串

我有方法返回的 JSON 字符串：

public List<Issues> Getdata(
        string jql,
        List<string> fields = null,
        int startAt = 0,
        int maxResult = 500)
    {
        string data = JsonConvert.SerializeObject(request);
        string result = runQuery(JiraResource.search, data, "POST"); //returns results and working fine
        SearchResponse response = JsonConvert.DeserializeObject<SearchResponse>(result);
        return response.IssueDescriptions = GetIssues(response);;
    }

JSON 字符串如下所示：

{"expand":"schema,names","startAt":0,"maxResults":50,"total":139,"issues":[{"expand":"operations,versionedRepresentations,editmeta,changelog,transitions,renderedFields","id":"20930","self":"https://clientname.atlassian.net/rest/api/2/issue/20930","key":"-139","fields":{"summary":"Rebate","issuetype":{"self":"https://clientname.atlassian.net/rest/api/2/issuetype/1","id":"1","description":"A fee negotiation or quote","iconUrl":"https://clientname.atlassian.net/images/icons/issuetypes/sales.png","name":"Fees","subtask":false},"components":[],"created":"2015-07-10T12:29:05.000+1000","description":"Execute as per attached instruction","project":{"self":"https://clientname.atlassian.net/rest/api/2/project/10013","id":"10013","key":"--","name":"Change Instructions","avatarUrls":{"48x48":"https://clientname.atlassian.net/secure/projectavatar?avatarId=10011","24x24":"https://clientname.atlassian.net/secure/projectavatar?size=small&avatarId=10011","16x16":"https://clientname.atlassian.net/secure/projectavatar?size=xsmall&avatarId=10011","32x32":"https://clientname.atlassian.net/secure/projectavatar?size=medium&avatarId=10011"}},"reporter":{"self":"https://clientname.atlassian.net/rest/api/2/user?username=rajap","name":"rajap","key":"rajap","emailAddress":"email.au","avatarUrls":{"48x48":"https://clientname.atlassian.net/secure/useravatar?avatarId=10142","24x24":"https://clientname.atlassian.net/secure/useravatar?size=small&avatarId=10142","16x16":"https://clientname.atlassian.net/secure/useravatar?size=xsmall&avatarId=10142","32x32":"https://clientname.atlassian.net/secure/useravatar?size=medium&avatarId=10142"},"displayName":"Prabu","active":true,"timeZone":"US"},"priority":{"self":"https://clientname.atlassian.net/rest/api/2/priority/3","iconUrl":"https://clientname.atlassian.net/images/icons/priorities/major.png","name":"Medium","id":"3"},"resolution":null,"duedate":"2015-07-15","comment":{"startAt":0,"maxResults":1,"total":1,"comments":[{"self":"https://clientname.atlassian.net/rest/api/2/issue/20930/comment/24290","id":"24290","author":{"self":"https://clientname.atlassian.net/rest/api/2/user?username=acahill","name":"acahill","key":"acahill","emailAddress":"email","avatarUrls":{"48x48":"https://clientname.atlassian.net/secure/useravatar?avatarId=10142","24x24":"https://clientname.atlassian.net/secure/useravatar?size=small&avatarId=10142","16x16":"https://clientname.atlassian.net/secure/useravatar?size=xsmall&avatarId=10142","32x32":"https://clientname.atlassian.net/secure/useravatar?size=medium&avatarId=10142"},"displayName":"Andrew Cahill","active":true,"timeZone":"US"},"body":"John, please action","updateAuthor":{"self":"https://clientname.atlassian.net/rest/api/2/user?username=acahill","name":"acahill","key":"acahill","emailAddress":"email","avatarUrls":{"48x48":"https://clientname.atlassian.net/secure/useravatar?avatarId=10142","24x24":"https://clientname.atlassian.net/secure/useravatar?size=small&avatarId=10142","16x16":"https://clientname.atlassian.net/secure/useravatar?size=xsmall&avatarId=10142","32x32":"https://clientname.atlassian.net/secure/useravatar?size=medium&avatarId=10142"},"displayName":"Andrew","active":true,"timeZone":"US"},"created":"2015-07-10T12:35:43.728+1000","updated":"2015-07-10T12:35:43.728+1000"}]},"votes":{"self":"https://clientname.atlassian.net/rest/api/2/issue/-139/votes","votes":0,"hasVoted":false},"assignee":{"self":"https://clientname.atlassian.net/rest/api/2/user?username=olearyj","name":"olearyj","key":"olearyj","emailAddress":"email","avatarUrls":{"48x48":"https://clientname.atlassian.net/secure/useravatar?avatarId=10142","24x24":"https://clientname.atlassian.net/secure/useravatar?size=small&avatarId=10142","16x16":"https://clientname.atlassian.net/secure/useravatar?size=xsmall&avatarId=10142","32x32":"https://clientname.atlassian.net/secure/useravatar?size=medium&avatarId=10142"},"displayName":"John","active":true,"timeZone":"US"},"status":{"self":"https://clientname.atlassian.net/rest/api/2/status/1","description":"The issue is open and ready for the assignee to start work on it.","iconUrl":"https://clientname.atlassian.net/images/icons/statuses/open.png","name":"Open","id":"1","statusCategory":{"self":"https://clientname.atlassian.net/rest/api/2/statuscategory/2","id":2,"key":"new","colorName":"blue-gray","name":"To Do"}}}}]}

我想要上述 json 字符串的解析器方法来获取这些字段值的特定值，例如：

“摘要”、“状态”、“受让人”、 “评论”、“描述”、“已创建”、“截止日期”、“环境”、“优先级”、“项目”、 “记者”、“决议”、“问题类型”、“更新”、“投票”、“组件”

我试图一一了解。然而，它很复杂且耗时。

这就是我正在努力的方式。但错误：对象引用未设置到对象的实例。

private List<JiraIssues> GetIssues(SearchResponse response)
{
    List<JiraIssues> returnResulttoReport = new List<JiraIssues>();
    foreach (var item in response.IssueDescriptions) //error here (not sure why IssueDescriptions is NULL but before call i'm de-serializing it)
    {
        foreach (var item1 in item.Comments)
        {

        }
    }

    return returnResulttoReport; 
}

我的返回类型是List<Issuees>。是否有任何库或示例链接可以执行此操作？

请注意，我已经对其进行了反序列化，现在我想要其中的特定列表。另外，请注意，我给出的 JSON 完整字符串与我实际拥有的不同。但它相似。请指导。

使用类似的东西json2csharp http://json2csharp.com/为 json 生成 C# 类，以防止错误。然后做类似的事情

var result = JsonConvert.DeserializeObject<RootObject>(myJsonString);

EDIT
以下是如何获取摘要的示例：

RootObject result = JsonConvert.DeserializeObject<RootObject>(json);

List<string> summaries = new List<string>();
foreach (var item in result.issues)
{
    var summary = item.fields.summary;
    Console.WriteLine(summary);
    summaries.Add(summary);
}

RootObject 将表示 JSON 的顶级对象，然后它将具有与 JSON 的每个属性相对应的属性。