如何以编程方式从viewmodel中选择listview项？

Question

I have a MVVM application with a MainWindowViewModel connected to a MainWindow view.
On the MainWindow view I have a ComboBox containing stock ticker symbols.

I have another viewmodel and view called AllStockQuoteViewModel connected to AllStockQuoteView which contains a list of stocks and their prices.

I want to be able to select an item from the ComboBox and have the item in the AllStockQuoteView selected and highlighted. On my MainWindowViewModel I have saved the reference to the AllStockQuoteViewModel and use it to call a method to find the stock ticker symbol in the ObservableCollection bound to the AllStockQuoteView , but haven't found a way to programmatically select the item on the AllStockQuoteView .

I have a SelectedQuote property on the AllStockQuoteViewModel bound to the listview on the AllStockQuoteView and I can select one of the items and my SelectedQuote property is set fine. If I set this programmatically in my SelectQuote method, it doesn't appear as if the item is selected in the view, although the item is passed back to the MainWindowViewModel and I can use it to populate the textblocks on MainWindow view.

I'd like to be able to show the item on the AllStockQuoteView as being selected via highlighting as if the user selected it.

How can this be done?

Answer 1

Its very easy to implement

You need two things in your view model A List of your objects and a selected item property

        private CustomObject _selectedCustomObject;

        public ObservableCollection<CustomObject> CustomObjects
        {
            get
            {
                return new ObservableCollection<CustomObject>();
            }
        }

        public CustomObject SelectedCustomObject
        {
            get { return _selectedCustomObject; }
            set
            {
                if (_selectedCustomObject== value)
                {
                    return;
                }

                _selectedCustomObject= value;
                PropertyChanged.Raise(this, x => x.SelectedCustomObject);
            }
        }

Then in your view you add your List/Combo control and bind to both properties.

<ListView ItemsSource="{Binding CustomObjects}"
          SelectedItem="{Binding SelectedCustomObject}">

Then all you need to do is set the viewmodel properties and the view will update.

Answer 2

First you have to think about your model and the whole MVVM approach, a good starting point is http://blogs.msdn.com/b/kashiffl/archive/2010/11/14/mvvm-technical-description.aspx .

After you can implement your functionality by different ways, one would be to implement something like the Observer Pattern or you try to use methods like Notify Property-Changed-Events .

Hope i was able to help,

Greetings