Hi,

You will need to use a CustomColumn to do that. We have several samples demonstrating how to use it. You can start from this one:

http://demo.essentialobjects.com/Demos/Grid/Features/Custom%20Column/Demo.aspx

Once you see how this sample works, you can proceed to the "Advanced" one:

http://demo.essentialobjects.com/Demos/Grid/Features/Custom%20Column%20-%20Advanced%202/Demo.aspx

You can find the documentation for CustomColumn here:

http://doc.essentialobjects.com/library/1/grid/custom_column.aspx

Note EditorTemplate is only rendered once for the whole Grid, so you can not have different drop downs for different cells by using EditorTemplate. If you wish to have different drop down for different cells, you will need to handle the CustomItem's ClientSideGetText to return raw HTML that renders as a drop down. The raw HTML will also need to include event handler JavaScript code that saves the changes back to the Grid when a change is made.

Hope this helps.

Thanks!