uncheck selected checkbox from check all in ext.js - extjs

Question

I have grid panel, its having check all options. But I'm stuck on the selected dataIndex which having value = 'N'. There is Y or N. If some rows having value N, it must not check when I click check all. I had already make validation on it. it's work. But I want also the uncheck is appear when i click check all if it's value is 'N'. This is my code
var sm;
sm = Ext.create('Ext.selection.CheckboxModel');
gridMain = Ext.create('Ext.grid.Panel', {
id: 'gridMyapproval',
renderTo: Ext.get("sa-grid"),
store: 'myapproval-store',
selModel: sm,
height: mainContentHeight - 63, //480//mainContentHeight-138,
//title: 'Request',
columns: [{
text: 'Request Type',
width: 100,
dataIndex: 'WorkflowType'
}, {
text: 'Requestor ID',
width: 100,
dataIndex: 'RequestedByID'
}, {
text: 'Requestor Name',
width: 200,
dataIndex: 'RequestedByName'
}, {
text: 'Description',
flex: 1,
dataIndex: 'RequestDescription'
}, {
text: 'Status',
width: 150,
dataIndex: 'RequestStatusDescription'
},
{
text: 'EnableApprove',
width: 150,
dataIndex: 'EnableApprove'
},
],
dockedItems: [{
xtype: 'toolbar',
items: [actApproveAll]
}],
listeners: {
itemdblclick: function (view, record, item, index, e, eOpts) {
isGridClicked = true;
ViewDetails(FormState.VIEW);
},
afterrender: function (row, model, index) {
//$('.x-column-header-checkbox').css('display','none');
if (model.data.EnableApprove == 'N') {
grid.getSelectionModel().deselect();
}
},
selectionchange: function (row, model, index) {
if (model.data.EnableApprove == 'N') {
grid.getSelectionModel().deselect();
}
},
beforeselect: function (row, model, index) {
if (model.data.EnableApprove == 'N') {
MsgBox("Enable Approve !");
return false;
}
}
}
});
I tried to write it on afterrenderer, but it's not work.

Answer 1

I think you have to overrite selectAll (source) and deselectAll (source) methods of Ext.selection.CheckboxModelView.
Check this question and answer, I guess solution is somewhat you need.