Object of type System.DBNull cannot be converted to type System.Nullable`1[System.Decimal]

Hello,

I am getting the above error when I try to change a grid value from a decimal number to null.  I am using an ObjectDataSource to populate a WebHierarchicalDataGrid, version 10.3.  I found a post elsewhere that suggested setting the ObjectDataSource property ConvertNullToDBNull to False, but in my case it is False already.  Any ideas?

Thank you,

Ross

Hello Ross,

 

Thank you for posting in our community. I found a lot of posts according to this error. It does not seems to be something connected with IG controls it is more because of the null values returned from the database. For some reason they are set to DBNull.Value. If you are able to provide us a simple sample that reproduces this issue. I could look into it and investigate it further.

 

Looking forward to hear from you.

 

Sincerely,

Georgi Sashev

Developer Support Engineer

Infragistics, Inc.

http://www.infragistics.com/support

Hi Georgi,

Thank you for your quick reply.  I put together a test project that reproduces this problem.  I couldn't attach the whole project because the default IG styles and graphics were loaded into it, so I just zipped up my code files.

Regards,

Ross

Hello Ross,

 

Thank you for the sample code. I am working on this. I was able to reproduce this exception. I will update you with my progress as soon as possible.

 

Sincerely,

Georgi Sashev

Developer Support Engineer

Infragistics, Inc.

http://www.infragistics.com/support

Hello Ross,

 

The only way this will work is to set

 

public class TestObject

{

       public int Key { get; set; }

       public decimal Amount { get; set; }

}

 

The amount like this. Which will prevent it to be null and this way when you delete the value in the column it will not throw an exception and the value shown in the grid will be 0.

 

I hope this helps.

 

Sincerely,

Georgi Sashev

Developer Support Engineer

Infragistics, Inc.

http://www.infragistics.com/support

While your answer has the virtue of being obvious, it is not helpful.  Can you do any better?  You are basically saying that the Infragistics grid doesn't handle nulls fully the way it should.  I can back that up with the fact I have tried this same exercise with other grids, and they work fine.

As a possible work-around, I am going to explore having the grid display all zero values as blank.  If you have anything to suggest on how to best make that work, that will be appreciated.  While it isn't a very satisfying answer, I have to get the job done, and it is too late to switch off the Infragistics grids right now.

Hello Ross,

 

Here I found this forum post:

 

you can try this approach. And let me know if it works in your case.

 

 

I hope this helps.

 

Sincerely,

Georgi Sashev

Developer Support Engineer

Infragistics, Inc.

http://www.infragistics.com/support

Thank you for the link.  It looks like it may be helpful, but I will need some time to try it out.  I will keep you posted.

Regards,

Ross

Hello Ross,

 

I am waiting for your update on this.

 

Sincerely,

Georgi Sashev

Developer Support Engineer

Infragistics, Inc.

http://www.infragistics.com/support

Yes, thank you for waiting.  I need a few days to get to this because of some other things that have come up.

Hello Ross,

 

Any update on this?

 

Sincerely,

Georgi Sashev

Developer Support Engineer

Infragistics, Inc.

http://www.infragistics.com/support

Hi Georgi,

Thank you for asking.  I hope to work on this by the end of this week.

Regards,

Ross

Hi Georgi,

I have tried to work with the link that you sent, but without success.  Because I need to move ahead with the project, I am going to try a different approach, displaying null values as zero on the screen and then storing them as null in the database.  The users may not go for it, and if not, then I will have to go back to the drawing board.  So, I wouldn't consider this question answered, but I am dropping the question indefinitely.

Regards,

Ross

Hello Ross,

 

Thank you for the update.

If you come back to this question or in case you have any other, do not hesitate to contact me, I will be glad to assist you.

 

Sincerely,

Georgi Sashev

Developer Support Engineer

Infragistics, Inc.

http://www.infragistics.com/support