Have some questions on grid

First question is whether there is a hidden property on grid column,because i want to hide some columns.
Second question.I want dynamically add/delete items to grid by js function,For example,i click a button and send ajax action to the server,then i get the information of deleting,but i don’t know how to search the ‘primary key’ of the grid according to the information i got before.From your ‘touch.chm’ document,there are lots of methods of grid have ‘id’ parameter.
Can you explain what means about the ‘id’ parameter?

In my app,i hope build treegrid by grid component,so i want dynamically add/delete by ajax.

There is no hidden property but you can store any amount of extra data in each row, you need not use hidden columns for that.

Each record in grid has ID, by default it is taken from “id” property of related json object or “id” attribute of xml tag. If you have not provide such element in the data - it will be auto-generated.

[{ "id":"1", "Package":"acx100-source", "Version":"20080210-1.1", "Maintainer":"Stefano Canepa <sc@linux.it>" },{
This is sample grid’s data - as you can see it contains “id” property. This value will be sent to all event handlers, and can be used in API methods to delete the row.

Thank you very much.you really help my a lot.
I understand the ‘id’ property of the gird better than before.
I realized treegrid style by grid component.
Below picture is my screenshot.

Could you please post a tree grid example to study.