JSON Feed an no values

John Riker

Have a program that calls up a URL of JSON data and loads it in and then starts processing it record by record. That said, sometimes the result can be just a header with no data for various reasons. When I try to process the results I end up getting the below due to no data:

Unhandled Exception: System.NullReferenceException: Object reference not set to an instance of an object.
at ShowWebsiteDownloader.Program.Main() in C:\Users\jriker\source\repos\ShowWebsiteDownloader\ShowWebsiteDownloader\Program.cs:line 97

So I read in the data:

rawJSON = webClient.DownloadString(showsurls);
ShowWebsiteDownloader.Rootobject rootObject = JsonConvert.DeserializeObject(rawJSON);

Then process the results

for (int loop = 0; loop < rootObject.tiles.Length; loop++)
{

So the before mentioned error is on the start of the for loop. Is there a way to check if any data exists after Deserializing?

4 Replies

Know the answer? Post it — somebody with the same question will find it here.

John Riker5y ago
The tiles value is null so I did the following check and seemed to resolve it:
if (rootObject.tiles != null) // Check if the show returned any data
{ ...
So if it's not null it processes, or it goes to an end else and outputs a debug log that there was no data.
Jaimin Shethiya5y ago
Hello

can you please tried the below code and checked.

if (rootObject?.tiles?.Any() == true)
{
   for (int loop = 0; loop < rootObject.tiles.Length; loop++)
   {
      ...
   }
}

Thanks
Rajanikant Hawaldar5y ago
this is very famous runtime error, do null check.
if(rootObject !=null && rootObject.tiles !=null)
{
    for (int loop = 0; loop < rootObject.tiles.Length; loop++)
    {
         // your code goes here
    }
}
Sachin Singh5y ago
Proceed like below
if(rootObject.titles.Any())
{

foreach(var item in rootObject.titles)
{

  var title= item.TitleName ?? "No title";

}
}