ERROR: Items collection cannot be modified when the DataSource property is set

Basically we get this error when we try to add a data into the combobox after binding the combobox by using datasource property. If we use to bind data in this way comboBox1.Items.Add then we didn't get any error. But if we want to add data after binding then we will get below error:

Items collection cannot be modified when the DataSource property is set.



Screenshot is given below:



Lets