How to solve error object reference not set to an instance of an object ?

Question

How to solve error object reference not set to an instance of an object ?

ahmed salah 3,216

I work on csharp i get error object reference not set to an instance of an object

code give me error

var Data = result.items.Select(e => new { PartID = e.create._id, IsUpdated = e.create.error != null && e.create.error.reason !=null && !e.create.error.reason.Contains("document already exists") ? 0 : 1, ErrorStatus = e.create.error == null  | (e.create.error.reason!=null && e.create.error.reason.Contains("document already exists")) ? null : e.create.error.reason }).ToList();

ElasticPartialUpdat.Create.error.get returned null.

so how to solve error please ?

Viorel 122.6K Reputation points

2022-08-14T18:29:06.827+00:00

Maybe "||" instead of "|" will work.
ahmed salah 3,216 Reputation points

2022-08-14T18:50:54.513+00:00

are there are another solution for solving that
ahmed salah 3,216 Reputation points

2022-08-14T18:53:16.647+00:00

error that display for me
is
error object reference not set to an instance of an object
AgaveJoe 30,126 Reputation points

2022-08-14T21:33:21.077+00:00

This is the most common error in programming and the easiest to find. Typically the error message tells you exactly what object is null.

Set a break point and use the watch window to find the null object. Once you find what is null then backtrack through your code to figure out why the object is not set. If your logic allows or expects a null object, then use the null coalesce operator or null conditional operator.

?? and ??= operators (C# reference)
?: operator (C# reference)
ahmed salah 3,216 Reputation points

2022-08-14T22:19:46.917+00:00

if i need to check object reference
if (Object.ReferenceEquals(null, myObjVar))
{
.......
}
so how to make it please
ahmed salah 3,216 Reputation points

2022-08-14T22:55:44.063+00:00

can any one help me
AgaveJoe 30,126 Reputation points

2022-08-15T10:57:54.5+00:00
You have to understand, the community cannot find the null objects because we do not have your data and cannot run your code. It is up yo you to run your code through the Visual Studio debugger to find what item(s) is null. Simply set a break point and find the null object(s).

First look at the Visual Studio Debugger

https://learn.microsoft.com/en-us/visualstudio/debugger/?view=vs-2022

For example "error" or "reason" could be null in the code below which will cause an exception.

e.create.error.reason.Contains("document already exists")

This is the main reason I suggested the null conditional operator above.

e.create?.error?.reason?.Contains("document already exists")

Please do not mindlessly copy the code above. Make an effort to read the documentation!

2 answers

Your answer

Viorel 122.6K Reputation points

2022-08-14T18:29:06.827+00:00

Maybe "||" instead of "|" will work.
ahmed salah 3,216 Reputation points

2022-08-14T18:50:54.513+00:00

are there are another solution for solving that
ahmed salah 3,216 Reputation points

2022-08-14T18:53:16.647+00:00

error that display for me
is
error object reference not set to an instance of an object
AgaveJoe 30,126 Reputation points

2022-08-14T21:33:21.077+00:00

This is the most common error in programming and the easiest to find. Typically the error message tells you exactly what object is null.

Set a break point and use the watch window to find the null object. Once you find what is null then backtrack through your code to figure out why the object is not set. If your logic allows or expects a null object, then use the null coalesce operator or null conditional operator.

?? and ??= operators (C# reference)
?: operator (C# reference)
ahmed salah 3,216 Reputation points

2022-08-14T22:19:46.917+00:00

if i need to check object reference
if (Object.ReferenceEquals(null, myObjVar))
{
.......
}
so how to make it please
ahmed salah 3,216 Reputation points

2022-08-14T22:55:44.063+00:00

can any one help me
AgaveJoe 30,126 Reputation points

2022-08-15T10:57:54.5+00:00

You have to understand, the community cannot find the null objects because we do not have your data and cannot run your code. It is up yo you to run your code through the Visual Studio debugger to find what item(s) is null. Simply set a break point and find the null object(s).

First look at the Visual Studio Debugger

https://learn.microsoft.com/en-us/visualstudio/debugger/?view=vs-2022

For example "error" or "reason" could be null in the code below which will cause an exception.

e.create.error.reason.Contains("document already exists")

This is the main reason I suggested the null conditional operator above.

e.create?.error?.reason?.Contains("document already exists")

Please do not mindlessly copy the code above. Make an effort to read the documentation!

Answer 1

Bruce (SqlWork.com) 77,766 Volunteer Moderator

you will need to determine which value is null:

in the caller it can be one of:

result
result.items

in the callback one of:

e
e.create

ahmed salah 3,216 Reputation points

2022-08-16T06:22:56.317+00:00

can you show me what you mean by

you will need to determine which value is null:

in the caller it can be one of:

result
result.items

in the callback one of:

e
e.create

Answer 2

Deba Khadanga 1

Use "||" instead of "|". "|" evaluates both operands for final result. In your case , the 2nd operand of "|" i.e e.create.error.reason is throwing object reference not set error.

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How to solve error object reference not set to an instance of an object ?

2 answers

Your answer