CODEWITHSUNDEEP
c#wpfbinding
Sk1X1
Sk1X1

Reputation: 1373

Default selected value in ComboBox

Im trying to set default value of ComboBox. I'm using binding in layout and I'm not sure how bind it right. Here is my viewModel:

public class ViewModel : INotifyPropertyChanged
{
    private Sklady sklady = null;

    public event PropertyChangedEventHandler PropertyChanged;
    private void NotifyPropertyChanged(String info)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(info));
        }
    }

    public Sklady Sklady
    {
        get
        {
            return this.sklady;
        }
        set
        {
            this.sklady = value;
            NotifyPropertyChanged("Sklady");
        }
    }
}

How I am set data to viewModel:

private void comboBoxSklad_Loaded(object sender, RoutedEventArgs e)
{
    //get some data
    prijemWindow.viewModel.Sklady = sklady;
    prijemWindow.viewModel.Sklady.skladID = prijemWindow.viewModel.Radky.radky[index].SKLAD;
}

My viewModel use this class to get values:

[DataContract]
public class Sklady
{
    [DataMember]
    public List<Sklad> sklady { get; set; }
    [DataMember]
    public String skladID { get; set; }

    public class Sklad
    {
        public string ID { get; set; }
        public string NAME { get; set; }
        public string CODE { get; set; }
    }
}

And this is current xaml code:

<ComboBox Name="comboBoxSklad" Loaded="comboBoxSklad_Loaded" ItemsSource="{Binding Sklady.sklady}" DisplayMemberPath="CODE"
        SelectedValuePath="ID" SelectedItem="{Binding Sklady.skladID}"/>

Data are binded into ComboBox correctly and I can see data from sklady List. But I would like to set the ComboBox default value to skladID value. How can I do it?

ANSWER

With answer from Klaus Byskov Pedersen I get it work... First, I use SelectedValue instead of SelectedItem... Then, I ininialize Sklady in constructor prijemWindow.viewModel.Sklady = new Sklady();prijemWindow.viewModel.Sklady = new Sklady(); and at the end, changed lines :

sklady.skladID = prijemWindow.viewModel.Radky.radky[index].SKLAD;
prijemWindow.viewModel.Sklady = sklady;

Thanks a lot!

Upvotes: 0

Views: 87

Answers (1)

Klaus Byskov Pedersen
Klaus Byskov Pedersen

Reputation: 121067

Use SelectedValue instead of SelectedItem.

<ComboBox Name="comboBoxSklad" Loaded="comboBoxSklad_Loaded" ItemsSource="{Binding Sklady.sklady}" DisplayMemberPath="CODE"
    SelectedValuePath="ID" SelectedValue="{Binding Sklady.skladID}"/>

When using SelectedItem the bound item would be of type Sklady, not string.

EDIT`

prijemWindow.viewModel.Sklady = sklady;
prijemWindow.viewModel.Sklady.skladID = prijemWindow.viewModel.Radky.radky[index].SKLAD;

You have a NotifyPropertyChanged when you set viewModel.Sklady but at the time this is fired, you have not yet set the skladID so try changing the order of those two statements.

Upvotes: 2

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