I don't think there's such a property.. If you want to emulate this behaviour you should have to set several properties like AllowEditing and even RowSelection.. I don't have infragistics installed in this machine so I cant tell you which ones and not even how many, but i'm pretty sure there's more than 5..
Now, if what you want to do is to prevent user from any kind of interaction with the webgrid, what you can do is to place the webgrid inside of a WebGroupBox and disable this control on your button's click.. Disabling the WGB will also 'disable' the webgrid within.
"Programming is an art form that fights back" _ Se habla español.