How to pass class reference in a hyperlink cell data of a tree panel ExtJS4

Hi,
I have a tree panel. It has a column that has a delete hyperlink for all the rows as shown below:

planName: someName,
deleteLink: '<a href="#" onclick="planRef.callClickMe();">Delete</a>'

where "deleteLink" is a dataindex in the tree panel as shown below:

Ext.define('PanelJS', {
extend: 'Ext.tree.Panel',
columns: [
{
xtype: 'treecolumn',
dataIndex: 'planName',
flex: 2
},
{
dataIndex: 'deleteLink',
tdCls: 'custom-column',
flex: 1
}]
}

But console says "planRef" is undefined when it is declared on class level, moreover I have checked the value of "planRef" before this line.

During debug mode when "planRef.callClickMe()" is watched it gives proper value. But at runtime, when screen is loaded and I click on the "Delete" link console says "planRef" is undefined.

I have even tried href config of NodeInterface but it does not show any hyperlink text.

I'm badly stuck into this issue. Help appreciated.

Thanks in advance,
Shweta

Instead of having the onClick attribute, use event listeners

Code:

---

component.getEl().on({
    click : someFn,
    scope : component,
    delegate : 'a'
});

---