On the form load event i want to populate my ComboBox1 to display unique items directly from the DB. For that i have set the DataSource property of the ComboBox1 to the selected field.

On the ComboBox1_SelectionChangeCommitted event i have set the filter for the DataSource which is working fine.

Now when i select an item from the ComboBox1 i get the filtered result in DataGridView but when i again drop down the combobox i see nothing other than the last selected item. Why is this happening? Is there a better way of populating ComboBox with the items directly from DB with default selected value as null?

Please help.