This question already has answers here:
What is a NullReferenceException, and how do I fix it?
(27 answers)
Closed 5 years ago.
I am trying to get Database Data to insert into List View
Error Code:
Unhandled Exception:
System.NullReferenceException: Object reference not set to an instance of an object. occurred
UPDATE 1:
Either shMsg or sqldb is null.
Put a breakpoint on line shMsg = FindViewById<TextView> (Resource.Id.shMsg);Then check if your resource is filled, and if you step 1 execution further, if the variable shMsg has a value.
Then proceed stepping until you realise which object has a null value.
The reason you get this exception is because you're trying to get a property of something that doesn't exist, because it's null.
If the sqldb variable is null, make sure you don't dispose of the connection to the database prematurely, which is a common mistake.
Related
This question already has answers here:
What is a NullReferenceException, and how do I fix it?
(27 answers)
Closed 3 months ago.
I am getting this error:
NullReferenceException: Object reference not set to an instance of an object Obstacle.OnTriggerEnter2D (UnityEngine.Collider2D collision) (at Assets/Scripts/Obstacle.cs:22)
There is no problem in the code. Where am I making a mistake?
[[enter image description here](https://i.stack.imgur.com/sSDkt.png)](https://i.stack.imgur.com/PRHdO.png)
Please help.
This is an issue caused by a small typo in the form of a lowercase ‘s’ instead of an uppercase ‘S’.
Because the Unity Engine was looking for Start and couldn’t find it, your “start” code never ran. Because of that, your Player was never assigned to, and had a “null reference”. And that’s why when you tried to read the tag, for a reference that was null, you got the error.
Your code should be:
private void Start ()
{
..
}
Note the exact case for Start and all C# commands.
This question already has answers here:
What is a NullReferenceException, and how do I fix it?
(27 answers)
Closed 1 year ago.
When I am inputting wrong username and password this error shows
this is my code
RegLog reuser = res.ResultAs<RegLog>(); //database result <-- Error Occurs here.
any solution? I already tried to declare it as var but error still persist.
Thank you.
It is because for some reason (probably wrong username and password), the variable res is null.
Try to check a null reference before using res.
Example: if(res == null) { //do something }
This question already has answers here:
What is a NullReferenceException, and how do I fix it?
(27 answers)
Closed 2 years ago.
I am using Visual Studio 2017 with the ASP.NET Core 2.1 Framework. When I try and loop through a static object I have in my controller, the iterator seems to be null.
The static object I am calling definitely has a collection seen below:
However When I try and see what the details are of the iterator I get a null reference exception even through the iterator should have a value:
What would be the cause of this null reference?
EDIT: Thanks to the answer I was able to debug what the issue was.
In the code where I am setting the bool wasFound I am doing a where query against a list of objects where the name of the incoming connection is in the list. In this case, the connection name was null and so it would fail.
Obviously the null reference error was a bit vague as to what was causing the error.
The problem is not with i itself, most probably the incoming instance is null, you can use ?. operator in this case:
i?.incoming?.connection
This question already has answers here:
What is a NullReferenceException, and how do I fix it?
(27 answers)
Closed 4 years ago.
When filtering a list using lambda where and contains, I get a NullReference error
var servers = _context.Servers.ToList();
servers = servers.Where(t => t.Technology.Contains(technology)).ToList();
But I get a this error:
Exception thrown: 'System.NullReferenceException' in
ServerBuildApp.dll ServerBuildApp.Models.Servers.Technology.get
returned null.
The list of servers contains a 'Technology' property and it contains the string I am passing it, for example "BIZ"
Any ideas? Or am I doing this completely wrong?
You need to check the t.Technology for null.
var servers = _context.Servers.ToList();
servers = servers.Where(t => t.Technology?.Contains(technology) is true).ToList();
You should check t.Technology for null and then check it contains.
This question already has answers here:
What is a NullReferenceException, and how do I fix it?
(27 answers)
Closed 7 years ago.
I'm getting System.NullReferenceException: Object reference not set to an instance of an object. Exception with below code.
string avblCount = "0";
if (!string.IsNullOrWhiteSpace(item.PART_AVAILABILITY.AVAIL_COUNT.ToString() as string))
{
avblCount = item.PART_AVAILABILITY.AVAIL_COUNT.ToString();
}
Exception occurred from this line.
if (!string.IsNullOrWhiteSpace(item.PART_AVAILABILITY.AVAIL_COUNT.ToString() as string))
How can i fix this ?
One or more of these entities are null:
item
item.PART_AVAILABILITY
item.PART_AVAILABILITY.AVAIL_COUNT
You should check which one is, and then act accordingly