WPF MVVM ComboBox SelectedItem or SelectedValue not working
- by cjibo
Update
After a bit of investigating. What seems to be the issue is that the SelectedValue/SelectedItem is occurring before the Item source is finished loading. If I sit in a break point and weight a few seconds it works as expected. Don't know how I'm going to get around this one.
End Update
I have an application using in WPF using MVVM with a ComboBox. Below is the ViewModel Example. The issue I'm having is when we leave our page and migrate back the ComboBox is not selecting the current Value that is selected.
View Model
public class MyViewModel
{
private MyObject _selectedObject;
private Collection<Object2> _objects;
private IModel _model;
public MyViewModel(IModel model)
{
_model = model;
_objects = _model.GetObjects();
}
public Collection<MyObject> Objects
{
get
{
return _objects;
}
private set
{
_objects = value;
}
}
public MyObject SelectedObject
{
get
{
return _selectedObject;
}
set
{
_selectedObject = value;
}
}
}
For the sake of this example lets say MyObject has two properties (Text and Id). My XAML for the ComboBox looks like this.
XAML
<ComboBox Name="MyComboBox" Height="23" Width="auto"
SelectedItem="{Binding Path=SelectedObject,Mode=TwoWay}"
ItemsSource="{Binding Objects}" DisplayMemberPath="Text" SelectedValuePath="Id">
No matter which way I configure this when I come back to the page and the object is reassembled the ComboBox will not select the value. The object is returning the correct object via the get in the property though.
I'm not sure if this is just an issue with the way the ComboBox and MVVM pattern works. The text box binding we are doing works correctly.
