Thank you for the provided code.
Before proceeding to your inquiry, I would like to clarify that RadDataFilter
is a completely separate component. From the provided information though, I assume that you refer to the RadGridView
control instead. If this is the case, the only scenario in which I guess such NullReferenceException would be raised, is if there is a column of type different than GridViewDataColumn defined. In such case you can simply add a null check for the column variable in order to ensure that the column is actually a GridViewDataColumn.
I hope this helps. Additionally, you can take a look at the Column Types
section from RadGridView's online help.
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