An MVVM way to know when a database update is complete in order to navigate to another page.

ToddHileHoffer

So, I have everything completed with no code in the code behind. I have everything separated. How should my view model notify the view that the database update has worked? Any thoughts or examples on how to do this?

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Pete OHanlon

You could simply add a dirty flag and bind to this.

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Lost User

Your VM needs to expose some property that indicates success or failure. You might need a converter because there are three or four states you're talking about: 1. Don't have a pending update 2. Have a pending update 3. Update failed 4. Update passed (2. is only appropriate for asynchronous updates) So your VM has a property that starts off with a value 1. When the 'save' command is triggered, it is set to 2. When the results of the Save are returned t is set to 3 or 4 respectively. You could 'merge' this with any process you are using to enable/disable the Save button - so add another state ... 0. Nothing To Save

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Abhinav S

Bind the status to a textblock and create a property for it in your view model (assuming everything is bound to the view model). Once your async web service comese back from the server, fire an action to get to the view model and then let INotifyPropertyChanged take over to update the status.

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ToddHileHoffer

This is what I did. I guess the user will have to click a link to navigate, or I can put that in the code behind. Thanks for the reply.

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Abhinav S

Strange. You should not need to - are the datacontext's correct?

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Mycroft Holmes

We use the MVVMlight framework from Galasoft, it has a messaging construct. In the completed method we send the name of the method via a Completed message pump, the relevant view or viewmodel subscribes to the Completed message, checks the message content and takes action as appropriate. We use a VERY simplified structure, I know it can get a lot more complex but this meets our current needs. However I rarely (never) use it to navigate as the datacontext generally meets our needs (data refreshes after the call and updates the UI via onpropertychanged)

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