how to display combo box or datepicker in grid

I've not actually tried this, and this assumes you are working with the DATAGRID object, but I believe what you need to do first is use the property builder for the grid (right-click on the grid) and change the column to a template. Then go into the HTML code behind the page, find the column definition, and change the text box attribute to appropriate type. Sorry if this doesn't work, but it's all I could suggest.