Extjs 4. How to parse grid store and change cell background dynamically? - extjs

Question

I have a grid, in which some rows with data are "inherited". That is, there are some parent rows and child rows. Child rows have the id_inherit field set to the id of the parent row. The grid is editable. Now I want to add some functionality which makes it possible to analyze changes in all child rows. If some value in some cell is different from that in the parent row, then I want to change the background of that particular cell in the inherited row. I want to do these analytics on the fly: in other words, I want to make it when the user hits the button. Now, I parse my grid rows like this:
var store = Ext.getCmp('grid').getStore();
store.each(function(record,idx){
if(record.get('id_inherit')!=0){ // grid row is inherited
// here I want to compare values in all cells of this row
// and the parent row, whose `id` is equal to record.get('id_inherit')
// if values are different in a particular cell of the inherited row, then
// I want to change its background color
}
});
EDIT
Now, without any comparison, I just try to change the cell color of all inherited rows, but it does not work. I do it like this:
store.each(function(record,idx){
if(record.get('id_inherit')!=0){
grid.getView().addRowCls(idx,'red');
// I guess I should have used addCls instead, but
// I do not know how to target a particular cell inside this record
// and change its class correctly
// but of course, I know column names and indices
}
});
And red style is defined like this:
.red {background-color: red !important;}
But it is not working. If I knew how to change the cell color dynamically, I could do all the other routines - comparing with parent rows, etc.
EDIT
I tried practically all solutions posted at StackOverflow and which seem to relate to some extent to my problem, but none of them work. What I want to stress again, is that I need to change the background color of a particular cell - NOT of the entire row and NOT of the entire column. And I want to do it on the button click - NOT inside the render function.
EDIT
I consulted this article ExtJS 4 Grid Change Cell Color , but the author manupulates the DOM of the selected row, and does it like this:
var selection = grid.getView().getSelectionModel().getSelection()[0];
var dom = (grid.getView().getSelectedNodes()[0]);
tds = Ext.get(dom).select("div");
Ext.get(tds.elements[evt.target.offsetParent.cellIndex]).addCls('black');
But in my case, where I iterate through the grid store, I do not know how to get to the dom of the current record, then select the div and add a custom class.
EDIT
Well, I tried thousands of tricks, but nothing works at all. If someone could advise me on how to parse a grid record to get to the cell HTML-structure, I would mark this advice as an answer. What I now know, inspecting the DOM structure, is, for example, that one of my cells has this CSS class x-grid-cell x-grid-cell-73892 x-grid-cell-last. What makes it unique is this part: x-grid-cell-73892. So, I tried to do it this way
store.each(function(record,idx){
var div = Ext.fly(record).query('x-grid-cell-73892').select('div')
....
});
But this is not working. Who would have thought, that such a trivial thing - the most trivial that I can imagine - that is to change the background color of a cell on button click, has no simple solution. At this point I have no solution, in fact.
EDIT
Well, I did it myself. The trick was to use the getCell function:
var column=grid.columns[index],
cell=grid.getView().getCell(record, column);
cell.addCls('mycss');