constants ReadOnlyEnum
Use the Enabled property to disable the control.

NameValueDescription
exReadWrite0 (boolean False) The control allows changes. The user can use the cell's editor to change the cell's value.  
exReadOnly-1 (boolean True) The control is read only and the cell's editor is not visible.
exLocked1 The control is read only, and the cell's editor is visible but locked. For instance, if the cell's editor contains a drop down portion, the user can display the drop down portion of the control, but it can't select a new value. Also, if the editor contains multiple buttons they are active as the control is not read only.