SelectedItem and SelectedValue returns the wrong item

Question

I have List<string> MyList with 4 values. These are shown in a ComboBox control. The binding works perfectly in my MVVM WPF project.

I also have a string SelectedMyList which binds to my XAML and is supposed to show the selected item. The problem I have is, regardless of using SelectedItem or SelectedValue, it always passes the first item in MyList

private MyClass()//constructor
{
    MyList = new List<string>() {"Hi", "Bye", "Hello", "See ya"}; 
}

private string _selectedMyList;
public string SelectedMyList
{
    get
    {
        return this._selectedMyList;
    }
    set
    {
        //value is always Hi
        if (this._selectedMyList== value)
            return;

        this._selectedMyList= value;
        OnPropertyChanged("SelectedMyList");
    }
}

private List<string> _myList;
public List<string> MyList
{
    get
    {
        return this._myList;
    }
    set
    {
        if (this._myList== value)
            return;

        this._myList= value;
        OnPropertyChanged("MyList");
    }
}

And my XAML

<ComboBox ItemsSource="{Binding MyList}" SelectedValue="{Binding SelectedMyList, UpdateSourceTrigger=PropertyChanged}" />

There are no errors/binding errors etc in the output window.

Why does the SelectedItem/SelectedValue not pass what I consider to be the selected item from the ComboBox?

have you set the `DataContext` either on xaml or code behind ? — Yuliam Chandra, Sep 06 '14 at 14:22
@YuliamChandra, if I hadn't set the DataContext, then how would MyList bind at all? — MyDaftQuestions, Sep 06 '14 at 14:32

score 0 · Accepted Answer · answered Sep 06 '14 at 14:25

This works for me.

  private string _selectedMyList;
    public string SelectedMyList
    {
        get
        {
            return this._selectedMyList;
        }
        set
        {
            //value is always Hi
            if (this._selectedMyList != value)
            {
                this._selectedMyList= value;
                OnPropertyChanged("SelectedMyList");
            }
        }
    }

    private List<ObservableCollection> _myList;
    public ObservableCollection<string> MyList
    {
        get
        {
            return this._myList;
        }
        set
        {
            if (this._myList== value)
            {
                this._myList= value;
                OnPropertyChanged("MyList");
            }
        }
    }

Xaml:

<ComboBox ItemsSource="{Binding MyList}" 
          SelectedItem="{Binding SelectedMyList}" 
          IsSynchronizedWithCurrentItem="True"/>

No idea why I need to sync it though... I'm suspecting there is something else going on but, this does resolve it. Thanks — MyDaftQuestions, Sep 06 '14 at 14:37

score 0 · Answer 2 · edited May 23 '17 at 12:15

0

If you want to use the SelectedValue attribute then you need to use it with the SelectedValuePath attribute. See this link to a similar question.

edited May 23 '17 at 12:15

Community

1
1

answered Sep 06 '14 at 14:41

Andrew N

502
7
20

SelectedItem and SelectedValue returns the wrong item

2 Answers2