Xaml - combo box - why does selectedValue NOT work with multiple columns? - wpf

Question

Hi and thanks for your help.
The following xaml works just fine:
<ComboBox Name="cboCit_type"
IsSynchronizedWithCurrentItem="True"
mvvm:View.FlowsWithPrevious="True"
ItemsSource="{Binding Path=cuCodeInfo.CitTypes}"
SelectedValuePath="code"
DisplayMemberPath="code"
Text="{Binding cit_type}"
IsEditable="true"
IsReadOnly="false"
SelectedValue="{Binding Path=cit_type}">
</ComboBox>
cuCodeInfo.CitTypes is simply a list of items that are available. There are a number of public properties, but the 2 in question are "code" and "description".
Right now, I show the available code values and the user selects one. If one was already selected, then it shows when the page is displayed. This is all good.
So then I thought it might be nice to show both the code and the description. I figured it shouldn't be too hard...
So I removed the DisplayMemberPath statement and added in an ItemTemplate.
When I did so everything looked great until I tried to select an item from the list. When I did so, instead of showing the selected code, I would get an empty string. I have searched the internet trying to find the one thing I need to add to the DataTemplate to fix this, but everything I have tried has failed. Here is the code that is NOT working:
<ComboBox Name="cboCit_type"
IsSynchronizedWithCurrentItem="True"
mvvm:View.FlowsWithPrevious="True"
ItemsSource="{Binding Path=cuCodeInfo.CitationTypes}"
SelectedValuePath="code"
Text="{Binding cit_type}"
IsEditable="true"
IsReadOnly="false"
SelectedValue="{Binding cit_type}">
<ComboBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal" >
<Border BorderThickness="0,0,1,0" BorderBrush="Black">
<TextBlock Text="{Binding Path=code}" mvvm:View.WidthEx="2" ></TextBlock>
</Border>
<TextBlock Text="{Binding Path=description}" mvvm:View.WidthEx="15" Margin="1" ></TextBlock>
</StackPanel>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
Any help will be greatly appreciated.
As an aside, I have to use this exact same format (same list, etc. just different SelectedValue) in a number of forms - so if you want to suggest the best way to do this in xaml, that would be nice. In my pre-xaml days, I would just create a control, set a property or 2, and use that in all my forms. But I am supposed to use xaml, so am not sure of the best way to do this.
Thanks!

Answer 1

I can't believe that I searched all over the net to find an answer and, until now, could not find one. The answer is as easy as I thought it should be.
Just replace:
DisplayMemberPath="code"
with
TextSearch.TextPath="code"
and the code works just fine.
Thanks to all who helped.

Answer 2

I can give you an idea how to use SelectedItem
ViewModel
public class ViewModel
{
public ViewModel()
{
//Suppose your collection CitTypes is Initialized and filled with there Items
//Now you can set first Element as selected in ComboBox
SelectedItem = CitTypes.FirstOrDefault();
}
CitType selectedItem;
public CitType SelectedItem
{
get { return selectedItem; }
set { selectedItem = value; RaisePropertyChanged("SelectedItem"); }
}
}
xaml
<ComboBox Name="cboCit_type"
IsSynchronizedWithCurrentItem="True"
mvvm:View.FlowsWithPrevious="True"
ItemsSource="{Binding Path=cuCodeInfo.CitationTypes}"
Text="{Binding cit_type}"
IsEditable="true"
IsReadOnly="false"
**SelectedItem="{Binding SelectedItem}"**>