[Solved] SelectedValue binded with Null

[Mohamed]

Hi all
In the detailView control'd template, I am using a RadComboBox with its SelectedValue binded.
When the binded column in the dataSource returns NULL it throws an exception. Is there a way to setup the RadCombo so to display nothing (empty string) when the binded value is NULL (Database null or .NET nullable type)?

[Collin]

You could use coalesce to pull back '' instead of null in the SQL statement of your dataset.

Instead of select myvalue

do

select coalesce(myvalue,'') as myvalue.

[Veselin Vasilev]

Hello Mohamed,

You can use ISNULL in your query as well:

SELECT ID, ISNULL(Name, '') as Name, Description FROM [Buildings]

All the best,
Veskoni
the Telerik team

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[Omar Shraim]

I have the same problem as Mohammad's. The suggested solution will not work in this case as my BL uses custom business objects generated by an ORM tool (LLBLGen). LLBLGen generates an entity for each table and if the table's column allows null, the resulting entity property would be a Nullable type.
example: Fund table has a Country column (GUID) that allows null. The generated FundEntity would have a Country property of type nullable GUID (GUID?).

The case becomes then when binding the ComboBox (or even a TexBox or DateTimePicker) to an entity property that is of a Nullable type, it throws a runtime exception if the source property has NULL but would work fine otherwise?

[Veselin Vasilev]

Hi Omar,

Which version of the Combobox do you use?
I tried to reproduce the problem but to no avail.
I have attached my files - you can bind it to your datasource and test.
When the value in the DB is null - the combobox shows empty text.


Best wishes,
Veskoni
the Telerik team

Instantly find answers to your questions at the new Telerik Support Center

[Omar Shraim]

Thank you for answering. The NULL problem I am having is not to do with DB NULL but rather with Nullable type NULL.
So if the datasource has a property FundId that is a nullable integer (int?) and the selectedValue of the comboBox is binded to this property, I get the exception when the property FundId.HasValue is false (meaning the nullableType is NULL) but works fine when the FundId.HasValue is true (meaning the nullableType is NOT NULL)?

[Veselin Vasilev]

Hi Omar,

Can you isolate the problem in a small and running project and attach it to a new support ticket please?
This will help us resolve the problem quicker.

Thanks

Best wishes,
Veskoni
the Telerik team

Instantly find answers to your questions at the new Telerik Support Center