nullreferenceexception was unhandled by user code

Question

Any help on this will be greatly appreciated. Whenever I run my program I get a NullReferenceException was unhandled by user code. here is the code selected while showing me this error var FollowResult = await _instaApi.FollowUserAsync(long.Parse(res.Value.Pk));

Nilesh Shah · Answer

you are using nulllable variable always use the check condition HasValue with nullable variables which I think you are missing. you line: var FollowResult = await _instaApi.FollowUserAsync( long .Parse(res.Value.Pk)); needs to change to: if (res.HasValue) { var FollowResult = await _instaApi.FollowUserAsync( long .Parse(res.Value.Pk)); } else { //do something else like validation message or error message }

Ilyas Zahir · Answer

nope the res.value its not null var res = await _instaApi.GetUserAsync(billis_spyros); here how it looks like the res.value

Bryian Tan · Answer

if res.value is NULL the code can't assess the PK property.

Nilesh Shah · Answer

but what is that .Pk? always post your relavent code together if you want some help post what is your return class definition?

Ilyas Zahir · Answer

i did that if (res != null) { var instagramid = res.Value.Pk; var FollowResult = await _instaApi.FollowUserAsync(instagramid); } else { MessageBox.Show(error); } and it select this line when it show the error var instagramid = res.Value.Pk;

Ilyas Zahir · Answer

on the res.value giving me null but it has string var res = await _instaApi.GetUserAsync(billis_spyros); var FollowResult = await _instaApi.FollowUserAsync(long.Parse(res.Value.Pk));

Bryian Tan · Answer

Try mouse hover the _instaApi  res and res.Value to see which one giving the NULL

Ilyas Zahir · Answer

i debug the code in visual studio and it show me the error and select this line i wrote here

Bryian Tan · Answer

Have you try to debug the code in Visual Studio? It could be _instaApi or res.Value is NULL. We can't tell by looking at one line of code.

Ilyas Zahir · Answer

pk it bring the iuser id because i can't use the follow method with just username need to bring user id