UWP ComboBox SelectedValue not working

Question

I'm writing a DB management app in c# using uwp and mvvm-light and I can't display a default selectedValue in my combobox without opening it and manually selecting one first.

Here is my view :

<ComboBox x:Name="editCategory" Header="Category" ItemsSource="{Binding Categories}" SelectedValue="{Binding CategoryCode, Mode=TwoWay}" SelectedValuePath="Code" DisplayMemberPath="Name"/>

Here's my ViewModel :

private ObservableCollection<Category> _categories;
public ObservableCollection<Category> Categories {
    get { return _categories; }
    set {
        if (_categories == value)
            return;
        _categories = value;
        RaisePropertyChanged("Categories");
    }
}

private int _categoryCode;
public int CategoryCode {
    get { return _categoryCode; }
    set {
        if (_categoryCode == value)
            return;
        _categoryCode = value;
        RaisePropertyChanged("CategoryCode");
    }
}

And my model :

class Category
    {
        public int Code { get; set; }
        [Required]
        public string Name { get; set; }
    }

I can display the different values when opening the combobox, when I select a value, it displays it correctly when the combobox is closed.

I know the binding is working because if I set a breakpoint in the setter of CategoryCode in my ViewModel, it shows the correct updated value.

The problem is that when I load the page, the default value is not selected when it should display the Category.Name of the item where Category.Code = CategoryCode

Please help me if you can, I've been searching for hours, and nothing I could find has helped me so far

Answer 1

I believe you need to set your SelectedItem or SelectedValue to the correct loaded variable before the form/control is loaded.