I'm trying to bind separate ComboBox cells within a DataGridView to a custom class, and keep getting an error

> 
> DataGridViewComboBoxCell value is not valid
> 
> 
> 

I'm currently assigning the data source for the cell to an `IList<ICustomInterface>` from a Dictionary I've got. Upon setting the data source however, the index for the `ComboBoxCell` isn't set, so it has an invalid value selected.

I'm trying to figure out how to get it to select a real value, e.g. the 0th item within the list it has been given to remove this error, or find another way to solve the problem. Anyone have any suggestions?