When will bindElement call the real service? - sapui5

Question

Main.view.xml:
<ObjectHeader
id="objectHeader"
title="{name}"
intro="{id}">
<headerContainer>
<IconTabBar
id="tabBar"
items="{
path: 'assigned',
parameters: {expand: 'b, c'}
}"
select="onTabBarSelect">
</IconTabBar>
</headerContainer>
</ObjectHeader>
Main.controller.js
onMasterSelectionChange : function (sPath) {
var oSource = oEvent.getParameter("listItem") || oEvent.getSource(),
// sPath = "/ASet('d')"
sPath = oSource.getBindingContext().getPath(),
oObjectHeader = this.byId("objectHeader");
oObjectHeader.bindElement(sPath);
this._oModel.attachEventOnce("requestCompleted", function(oEvent) {
var oTabBar = this.byId("TabBar");
oFirstListItem = oTabBar.getItems()[0],
sObjectId = oFirstListItem.getBindingContext().getProperty("id"),
sDPath = "/DSet('" + sObjectId + "')";
this._getControls(sDPath);
}, this);
}
I found a strange behavior: when I change the master list selection, sometimes Network will show a "/ASet/assigned" call, but sometimes there will be no call, which cause requestCompleted not fired.
According to: SAPUI5 - bindElement doesn't work the second time,
If you call bindElement with the same path twice, the second time won't actually trigger a new call to get new data, since the path didn't change.
But I am sure it is different path. Is there any way that can trigger this call?
BTW
oObjectHeader.bindElement({
path : sPath,
events: {
change : function (oData, test) {
},
dataRequested : function (oData) {
},
dataReceived: function (oData) {
}
}
});
change can be fired every time I click master list, but dataRequested and dataReceived is never called.

Answer 1

I know this is an old post but you can actually trigger a network call for the bindElement by refreshing the binding within its change event.
this.getView().bindElement({
path: "model>/" + sContextPath,
events: {
change: function (oEvent) {
// Get the context binding object
var oContextBinding = oEvent.getSource();
// Refresh the binding.
// This triggers a network call.
oContextBinding.refresh(false);
}.bind(this)
}
});
Refreshing the binding, triggers the network call. Also, set the bForceUpdate flag of the refresh to false so that it would only update the UI if there is a change in the data as mentioned in the APIs.

Answer 2

If your ODataModel has already loaded the data under sPath (check in myODataModel.oData) it will not load that data again. Therefore dataRequested/dataReceived will not fire.
But change should fire whenever the path changes no matter if data existed or not.

Answer 3

I find a work around by replace bindElement by change&oModel.read ...
onMasterSelectionChange : function (sPath) {
var oSource = oEvent.getParameter("listItem") || oEvent.getSource(),
// sPath = "/ASet('d')"
sPath = oSource.getBindingContext().getPath(),
oObjectHeader = this.byId("objectHeader");
oObjectHeader.bindElement({
path : sPath,
events: {
change : this._onBindingChange.bind(this, sPath)
}
})
},
_onBindingChange : function(sPath) {
this._oModel.read(sPath + "/assigned", {
urlParameters: {
"$expand": "b, c"
},
success: function(oData) {
var aAssigmentSet = oData.results,
oViewModel = this.getModel("viewModel"),
oTabBar = this.byId("hazardTabBar");
oViewModel.setProperty("/aAssigmentSet", aAssigmentSet);
oTabBar.bindAggregation("items",
"viewModel>/aAssigmentSet",
new sap.m.IconTabFilter({
key: "{viewModel>id}",
tooltip : "{viewModel>id}",
text : {
parts: [{path: "viewModel>b/name"},
{path: "viewModel>c/type"}],
formatter : function(name, type) {
var sType = type.split(".");
return name + " (" + sType[sType.length - 1] + ")";
}
}
})
);
if (oTabBar.getItems().length > 0) {
var sSelectedTabKey;
sSelectedTabKey = oTabBar.getItems()[0].getKey();
oTabBar.fireSelect({selectedKey: sSelectedTabKey});
}
}.bind(this),
error: this.errorCallback.bind(this)
});
},
onTabBarSelect : function(oEvent) {
var sRiskAssignmentPath = "/AssignmentSet('" + oEvent.getParameter("selectedKey") + "')";
this._oModel.read(AssignmentSet + "/assignedAssignedControls", {
...
});
}

Answer 4

I think the propper way to achieve this would be to use the invalidate-Method form Odata-Model.
This invalidates all cached entries and forces a new read for the Bindings:
https://sapui5.hana.ondemand.com/#/api/sap.ui.model.odata.v2.ODataModel%23methods/invalidate