将对象的值绑定到存储在列表中的组合框

Question

I want to bind a value of each object stored in a ObersvableCollection to the ComboBox. Unfortunately it doesn't work.

<ComboBox Grid.Column="1" Margin="0,0,0,5" VerticalContentAlignment="Center" HorizontalContentAlignment="Center" FontSize="15" ItemsSource="{Binding Path=UserAccounts}" >
    <ComboBox.ItemTemplate>
        <DataTemplate>
            <TextBlock Text="{Binding EMailAddress}"/>
        </DataTemplate>
    </ComboBox.ItemTemplate>
</ComboBox>

In the code behind I set the DataContext:

this.DataContext = PersitentDataModelUserSettings.Instace.UserAccounts;

Here is the Model:

public class PersitentDataModelUserSettings : ModelBase
{
    private static PersitentDataModelUserSettings instance = new PersitentDataModelUserSettings();

    public static PersitentDataModelUserSettings Instance
    {
        get { return instance; }
        set { instance = value; } 
    }

    private ObservableCollection<AccountSettingsObj> _userAccounts = new ObservableCollection<AccountSettingsObj>();

    public ObservableCollection<AccountSettingsObj> UserAccounts
    {
        get { return _userAccounts; }
        set
        {
            _userAccounts = value;
            OnPropertyChanged("UserAccounts");
        }
    }
}

This is the object type:

[XmlRoot]
public class AccountSettingsObj : ModelBase
{
    public string FirstName { get; set; }

    public string LastName { get; set; }

    private string _eMailAddress; 
    public string EMailAddress 
    {
        get { return _eMailAddress; }
        set 
        {
            _eMailAddress = value;
            OnPropertyChanged("EMailAddress");
        }
    }
}

Thanks!

Answer 1

You are setting ItemSource of comboBox to this:

ItemsSource="{Binding Path=UserAccounts}"

but you also setting DataContext of ComboBox to this:

this.DataContext = PersitentDataModelUserSettings.Instace.UserAccounts;

So binding engine is looking for property UserAccounts in UserAccounts .

---

This can be fixed in two ways:

• Either set ItemsSource to binding like this: ItemsSource="{Binding}" . This way you are saying ItemSource is same as DataContext of ComboBox.

• Or set DataContext to instance only : this.DataContext = PersitentDataModelUserSettings.Instace.UserAccounts; . This way you set DataContext to point to instance of PersitentDataModelUserSettings and asking BindingEngine to look for property UserAccounts in PersitentDataModelUserSettings .