Updating model does not always result in updated view

Question

I'm using SAPUI5 to make an application and I'm having an issue with an update to the model not being reflected immediately in the view.

A slightly simplified scenario: I created a text field that is taking its text from the model:

currentText = new sap.m.Text({
    width: '100%',
    text: '{/currentTrip/perHour}'
});

Then I create a select and attach a change handler:

sourceSelect.attachChange(oController.changeTripSource);

Inside that controller function I'm updating the view model:

var model = this.getView().getModel().getData();
model.currentTrip.perHour = 5;

All the things I do with this number flowing from this change event work (like updating a connected graph, which uses this number directly). The view itself however will not reflect the change to the model until I take another action like push a button or something. I'm not understanding why that is, or what triggers UI5 to check the changed values to the model and update the view. Does anyone have a fix for this?

See the answer by @matbtt; you should never update model properties directly, always use model.setProperty("/path/to/your/property", oSomeData); -- and getProperty("/path/to/your/property"); for retrieving data from the model — Qualiture
For other readers: this answer might also help: stackoverflow.com/a/48157104/5846045 — Boghyon Hoffmann

matbtt matbtt · Accepted Answer · 2015-03-09T20:16:19

Why don't you call setProperty() on the model directly? This saves you superfluous calls to update your bindings as the model will do it internally.

model.setProperty("/currentTrip/perHour", 5);

By the way, I don't see why updateBindings() shall work while refresh does not. Both methods call the checkUpdate() behind the curtains.

Updating model does not always result in updated view

2 Answers