Reason analysis and solution of Extjs inheritance Ext.data.Store not function _extjs

There are many kinds of reasons for this, I just say I met
I'm writing store-and-rifle.

Copy Code code as follows:

Docstore = Ext.extend (ext.data.store,{
Initcomponent:function () {
This.proxy = new Ext.data.HttpProxy ({url:this.url});
This.reader = new Ext.data.JsonReader (
{
Totalproperty: ' Results ',
Root: ' Rows ',
ID: ' DocId ',
Fields: [' docid ', ' extention ', ' docname ', ' author ', ' Sizes ', ' datecreated ']
}

);
This.sortinfo = {field: ' DateCreated ', direction: ' DESC '};
This.remotesort = false;
DocStore.superclass.initComponent.call (this);
}
});

It's not going to work when it's written in the store.
Because the Ext.data.Store class does not inherit the component component and therefore does not invoke the Initcomponet method at initialization time,
So the configuration items are not loaded into the store.