nullreferenceexception was unhandled by user code

Ilyas Zahir

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));

10 Replies

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Ilyas Zahir8y ago
nope the res.value its not null

var res = await _instaApi.GetUserAsync("billis_spyros");
here how it looks like the res.value
Bryian Tan8y ago
if res.value is NULL, the code can't assess the PK property.
Ilyas Zahir8y ago
pk
it bring the iuser id
because i can't use the follow method with just username need to bring user id
Nilesh Shah8y ago
but what is that .Pk?

always post your relavent code together if you want some help

post what is your return class definition?
Ilyas Zahir8y ago
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;
Nilesh Shah8y ago
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 Zahir8y ago
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 Tan8y ago
Try mouse hover the _instaApi , res and res.Value to see which one giving the NULL
Ilyas Zahir8y ago
i debug the code in visual studio and it show me the error and select this line i wrote here
Bryian Tan8y ago
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.