I have a list of DateTime items for a xamComboEditor, I am trying to make the combobox show the selecteditem in a 'MM-dd-yyyy' format, but unsuccessful. when the app first starts, it always show the selecteditem as '10/11/2015 12:00 AM'. I was able to set the dropdown list to be in the 'MM-dd-yyyy' format, but once the combobox losses focus, it will show the date in the 'dd/MM/yyyy HH:mm AM' format.

The xaml:

<Window x:Class="WpfApplication7.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:WpfApplication7"
xmlns:igWpf="http://schemas.infragistics.com/xaml/wpf"
mc:Ignorable="d"
Title="MainWindow" Height="350" Width="525">
<Grid>
    <Grid.ColumnDefinitions>
        <ColumnDefinition/>
        <ColumnDefinition/>
    </Grid.ColumnDefinitions>

    <igWpf:XamComboEditor 
          ItemsSource ="{Binding DateList}"
          SelectedItem="{Binding SelectedDate}">
          <igWpf:XamComboEditor.ComboBoxStyle>
                  <Style TargetType="ComboBox">
                          <Setter Property="ItemTemplate">
                                  <Setter.Value>
                                       <DataTemplate>
                                               <TextBlock Text="{Binding StringFormat='MM-dd-yyyy'}"/>
                                        </DataTemplate>
                                   </Setter.Value>
                             </Setter>
                      </Style>
                  </igWpf:XamComboEditor.ComboBoxStyle>
      </igWpf:XamComboEditor>

      <TextBox Grid.Column="1"/>
</Grid>
</Window>

Codes behind:

public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();

DateList = new ObservableCollection<DateTime>()
{
new DateTime(2005,09,15),
new DateTime(2015,10,15),
new DateTime(2015,11,15)
};
SelectedDate = DateList[1];
DataContext = this;
}

private ObservableCollection<DateTime> _DateList;
public ObservableCollection<DateTime> DateList
{
get { return _DateList; }
set
{
if (value != _DateList)
{
_DateList = value;
//RaisePropertyChanged();
}
}
}

private DateTime _SelectedDate;
public DateTime SelectedDate
{
get { return _SelectedDate; }
set
{
if (value != _SelectedDate)
{
_SelectedDate = value;
//RaisePropertyChanged();
}
}
}

}

I also have tried the following:

<igWpf:XamComboEditor.ComboBoxStyle>
    <Style TargetType="ComboBox">
        <Setter Property="IsEditable">
            <Setter.Value>False</Setter.Value>
        </Setter>
        <Setter Property="ItemStringFormat">
              <Setter.Value>MM-dd-yyyy</Setter.Value>
         </Setter>>
     </Style>
</igWpf:XamComboEditor.ComboBoxStyle>

but getting the same result.

Thanks.