是什么导致一个方法传递空值?

Question

所以我写了一个代码方法，它正确地从数据库中提取(我使用Dapper)，但它没有传递到下一个方法。谁能告诉我为什么，我做错了什么?不太明白我哪里做错了。我已经尝试了几种不同的方法，包括下面和制作IEnumerable列表。我可以看到记录器中的变量，所以我知道我正确地拉动它们，只是不确定为什么它们不发送到CheckSite()。

public class UptimeService
{
private readonly ILogger<UptimeService> _logger;
private readonly IWebsiteData _webdb;
private readonly IUptimeData _db;
public UptimeService(IWebsiteData webdb, IUptimeData db ,ILogger<UptimeService> logger) 
{
_webdb = webdb;
_logger = logger;
_db= db;
}
public class SiteResponse
{
public int Websiteid { get; set; }
public string Name { get; set; }
public string Url { get; set; }
public bool Status { get; set; }
public long ResponseTime { get; set; }

}

public async Task GetAllWebsites()
{

var websites = await _webdb.GetWebsites();

foreach (var website in websites)
{

_logger.LogInformation($"WEBSITE::::: {website.Url} | {website.Name} | {website.Websiteid}");
CheckSite(website.Url, website.Name, website.Websiteid);
}
return ;

}
public SiteResponse CheckSite(string Url, string Name, int Websiteid)

{
var result = new SiteResponse();
var stopwatch = new Stopwatch();
stopwatch.Start();
var client = new HttpClient();
_logger.LogInformation(
$"TEST URL: {result.Url}");
try
{
var checkingResponse = client.GetAsync(Url).Result;

result.Status = checkingResponse.IsSuccessStatusCode &&
checkingResponse.StatusCode == HttpStatusCode.OK;
}
catch
{
result.Status = false;
// offline
}
stopwatch.Stop();
var elapsed = stopwatch.ElapsedMilliseconds;
result.ResponseTime = elapsed;

if (result.Status)
{
// archive record
RecordToDb(result);
}
else
{
_logger.LogInformation(
$"Status is {result.Status}");
}
return result;
}

public async void RecordToDb(SiteResponse response)
{
var newRecord = new UptimeModel
{
Time = DateTime.Now,
Status = response.Status,
ResponseTime = (int)response.ResponseTime,
Websiteid = response.Websiteid,
Name = response.Name,

};
_logger.LogInformation(
$"Trying to Save {response.Name}");
await _db.InsertUptime(newRecord);
}

}

Answer 1

如果result.Url为空:

_logger.LogInformation($"TEST URL: {result.Url}");

这是因为它是SiteResponse()方法的一个新实例。

如果显示为null，则需要在类上创建构造函数。下面是一个例子:

public class SiteResponse
{
public SiteResponse(){  }
public SiteResponse(string url){
Url = url;
}
public int Websiteid { get; set; }
public string Name { get; set; }
public string Url { get; set; }
public bool Status { get; set; }
public long ResponseTime { get; set; }
}

，然后初始化新的

var result = new SiteResponse(Url);

根据下面的注释，我将重构为如下内容:

public class UptimeService
{
private readonly ILogger<UptimeService> _logger;
private readonly IWebsiteData _webdb;
private readonly IUptimeData _db;
public UptimeService(IWebsiteData webdb, IUptimeData db ,ILogger<UptimeService> logger) 
{
_webdb = webdb;
_logger = logger;
_db= db;
}
public class SiteResponse
{
public int Websiteid { get; set; }
public string Name { get; set; }
public string Url { get; set; }
public bool Status { get; set; }
public long ResponseTime { get; set; }
}
public async Task GetAllWebsites()
{

var websites = await _webdb.GetWebsites();
foreach (var website in websites)
{

_logger.LogInformation($"WEBSITE::::: {website.Url} | {website.Name} | {website.Websiteid}");
await CheckSite(website);
}
return ;

}
public async Task CheckSite(SiteResponse siteResponse)
{
var stopwatch = new Stopwatch();
stopwatch.Start();
var client = new HttpClient();
_logger.LogInformation(
$"TEST URL: {siteResponse.Url}");
try
{
var checkingResponse = await client.GetAsync(siteResponse.Url);

siteResponse.Status = checkingResponse.IsSuccessStatusCode &&
checkingResponse.StatusCode == HttpStatusCode.OK;
}
catch
{
siteResponse.Status = false;
// offline
}
stopwatch.Stop();
var elapsed = stopwatch.ElapsedMilliseconds;
siteResponse.ResponseTime = elapsed;

if (siteResponse.Status)
{
// archive record
RecordToDb(siteResponse);
}
else
{
_logger.LogInformation(
$"Status is {siteResponse.Status}");
}
return;
}

public async void RecordToDb(SiteResponse response)
{
var newRecord = new UptimeModel
{
Time = DateTime.Now,
Status = response.Status,
ResponseTime = (int)response.ResponseTime,
Websiteid = response.Websiteid,
Name = response.Name,

};
_logger.LogInformation(
$"Trying to Save {response.Name}");
await _db.InsertUptime(newRecord);
}    
}