ComboBox with some entries display only

I am using a combobox field in a databound grid. Certain data is display only based on the value of the data in that field. I am doing this with the rowenter event setting cancel to true if the condition is met. However I need to prevent the user from changing any other rows to this type. What is the best way to either remove the selections when showing the dropdown (fyi this is dropdown mode only) or prevent the grid from accepting one of those entries and reverting it back immediately?

I am not sure I fully understand what you are describing. Do you want to dynamically specify the dropdown list for a combobox? If so, you can do this in CurrentCellShowingDropDown. Here is a FAQ link that has a sample showing one way to do this. http://www.syncfusion.com/KB/Grid/Grid_c39c.asp#q567q