WinUI3 C++WinRT Issue sharing class to all view models.

Ryan Gallagher 21

How do I share data bindings across pages? I have my MainWindow and am trying to use a frame to navigate to sub pages. These sub pages need access to the bindings of the mainWindow. I am using C++ and most examples have each view model self contained or don't go far enough to show how to share a view model. They simply show passing of information through their click handler. If there is an answer to this in C++WinRT please point me towards it. I was thinking of instantiating the view model on the app level and then referencing it across each View model.

Thank you.

Roy Li - MSFT 32,731 Reputation points Microsoft Vendor

2021-12-10T01:56:49.217+00:00

Could you please tell me what do you mean by share data bindings across pages? What exactly behavior do you want to get? If you want to send the parameter to another page, just set the parameter in the Frame.Navigate() method, no matter it is a viewmodel or something else.
Ryan Gallagher 21 Reputation points

2021-12-14T04:19:59.07+00:00

I have instantiated a ViewModel in the MainPage.cpp for the main page to access bindings from.
I want to access that instantiated view model on another XAML page to access a reference of the ViewModel instantiated on the main page.

I have a IVector that holds the data for the entire app and I would like to use it across all pages.
Roy Li - MSFT 32,731 Reputation points Microsoft Vendor

2021-12-14T06:08:36.233+00:00

So did you try to pass the ViewModel as a parameter when you navigate to another page from MainPage?
Roy Li - MSFT 32,731 Reputation points Microsoft Vendor

2021-12-14T06:13:46.633+00:00
There are also two other possible ways for your scenario.

You could create a singleton class for your app, make the ViewMode a property of that class, You could access the singleton class from different pages instead of passing the ViewModel to different pages.

Make an event handler in the MainPage, When you need to do something with the ViewModel, send an event from other pages to the MainPage
Ryan Gallagher 21 Reputation points

2021-12-15T04:41:52.857+00:00

I will research into navigation, thank you. I could not figure out how to reference it on the other pages. I will look. If you know where off the top of your head please link it.

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WinUI3 C++WinRT Issue sharing class to all view models.