Getting null reference exception when add empty string to list

Question

This is my code..I cant add a null value to the list.Getting null reference exception.how to avoid it

List<string> lst = new List<string>();
 var empPersonal = context.tblEmployeePersonalDetails.Where(x => x.isDelete == false && x.empId == id).First();
lst.Add(empPersonal.gender.ToString() != null ? empPersonal.gender.ToString() :string.Empty);

In almost all cases NullReferenceException is same. Refer [What is a NullReferenceException and how do I fix it?](http://stackoverflow.com/questions/4660142/what-is-a-nullreferenceexception-and-how-do-i-fix-it) — Sriram Sakthivel, May 21 '15 at 07:23
`NullReferenceException` doesn't mean that the *item* you're adding is `null`. You can add a null string to the list without problems. What the runtime is telling you is that you are trying to access a property on a reference which points to `null`.E.g.: 1) `context` is null, but you are accessing `context.tblEmployeePersonalDetails`, or 2) `empPersonal` is null, but you are accessing `empPersonal.gender`, or 3) `empPersonal.gender` is null, but you are accessing `empPersonal.gender.ToString()`. You might also want to use `FirstOrDefault` instead of `First`. — Groo, May 21 '15 at 07:27

score 1 · Answer 1 · answered May 21 '15 at 07:22

1

List<string> lst = new List<string>();
var empPersonal = context.tblEmployeePersonalDetails
    .FirstOrDefault(x => x.isDelete == false && x.empId == id);
lst.Add(empPersonal != null ? empPersonal.gender.ToString() :string.Empty);

answered May 21 '15 at 07:22

Szer

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score 1 · Answer 2 · answered May 21 '15 at 07:23

1

If empPersonal.gender is null, calling empPersonal.gender.ToString() will yield an error.

What you probably meant to write was:

lst.Add(empPersonal.gender != null ? empPersonal.gender.ToString() : string.Empty);

answered May 21 '15 at 07:23

Heinzi

151,145
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326
481

score 0 · Answer 3 · answered May 21 '15 at 07:23

Perhaps

Change

lst.Add(empPersonal.gender.ToString() != null ? empPersonal.gender.ToString() :string.Empty);

To

lst.Add(empPersonal != null && empPersonal.gender != null ? empPersonal.gender.ToString() :string.Empty);

This catches empPersonal is null and the empPersonal.gender is null because both could be null.

Getting null reference exception when add empty string to list

3 Answers3