wpf programatically set combobox selected item when bound to dictionary

Question

I have a combobox which is bound do a dictionary

Dictionary<String, myClass> boxItems;

The combobox has the following dataTemplate:

<DataTemplate>
    <TextBlock Text="{Binding Path=Key}"></TextBlock>
</DataTemplate>

This works fine for loading the values and getting the selected value, however I can't figure out how to set the selected value from codebehind.

any pointers?

I've tried setting selectedItem and selectedValue to a Key (which I know is in the dictionary), but when I load the page, the combobox hasn't selected anything.

Answer 1

Add this to your ComboBox

<ComboBox SelectedItem="{Binding SelectedBoxItem}"/>

And use this in a class that implements INotifyPropertyChanged:

private myClass _selectedBoxItem;
public myClass SelectedBoxItem
{
    get { return _selectedBoxItem; }
    set
    {
        _selectedBoxItem = value;
        OnPropertyChanged("SelectedBoxItem");
    }
}

Answer 2

You need to create a KeyValuePair with the key you want to select.

You can do something like this:

 myCombo.SelectedItem = new KeyValuePair<string, int>("myKey", boxItems["myKey"]);