for (int i = 0; i < list_otdel.Items.Count; i++)
           {
            eform_sampling_Result record_list_Inst = list_otdel.Items[i] as eform_sampling_Result;
            if (record_list_Inst != null)
            {
           z_otdelDomainDataSource.Load();
           var record_Inst = ResourceWrapper.CurrentDomainContext.z_otdel_proc_Results.FirstOrDefault(r => r.indx ==record_list_Inst.eform);
           comboBoxOtdel.SelectedItem = record_Inst;
            }
         }

<dxe:ComboBoxEdit Name="comboBoxOtdel" DisplayMember="name" ItemsSource="{Binding ElementName=z_otdelDomainDataSource, Path=Data}" PopupClosed="comboBoxOtdel_PopupClosed" Grid.Row="2" Margin="15,5,0,0" Width="240"  HorizontalAlignment="Left" Height="28" VerticalAlignment="Top" Grid.Column="1">
            <dxe:ComboBoxEdit.StyleSettings>
                <dxe:CheckedComboBoxStyleSettings />
            </dxe:ComboBoxEdit.StyleSettings>
        </dxe:ComboBoxEdit>

 <dx:GroupFrame Header="Отделение" HorizontalAlignment="Left" Width="266" Height="171" VerticalAlignment="Bottom" Grid.Row="1" Grid.RowSpan="2" Grid.Column="1" Margin="0,0,0,6"></dx:GroupFrame>
        <dxe:ComboBoxEdit Name="comboBoxOtdel" DisplayMember="name" ItemsSource="{Binding ElementName=z_otdelDomainDataSource, Path=Data}" 
                          PopupClosed="comboBoxOtdel_PopupClosed" Grid.Row="2" Margin="15,5,0,0" Width="240" 
                          HorizontalAlignment="Left" Height="28" VerticalAlignment="Top" Grid.Column="1" 
            <dxe:ComboBoxEdit.StyleSettings>
                <dxe:CheckedComboBoxStyleSettings />
            </dxe:ComboBoxEdit.StyleSettings>
        </dxe:ComboBoxEdit>
        <ListBox Grid.Row="1" Height="120" HorizontalAlignment="Left" Name="list_otdel" VerticalAlignment="Bottom" Width="240" 
                 ItemsSource="{Binding Mode=OneWay, ElementName=eform_sampling_procDomainDataSource, Path=Data}" 
                 Margin="15,0,0,0"  DisplayMemberPath="name" Grid.Column="1" />

   LoadOperation<eform_sampling_Result> loadeform_sampling = MainContext.Load(
                    MainContext.Geteform_samplingQuery(Indx_spec));
   list_otdel.ItemsSource = loadeform_sampling.Entities;

 <riaControls:DomainDataSource AutoLoad="True" d:DesignData="{d:DesignInstance my:z_otdel_proc_Result, CreateList=true}"
                                      Height="0" Name="z_otdelDomainDataSource" QueryName="Getz_otdel_procQuery" 
                                      Width="0"  DomainContext="{StaticResource DomainContext}" Margin="0,0,237,316">
        </riaControls:DomainDataSource>

SELECT [CategoryID]
      ,[CategoryName]
      ,[Description]
      ,[Picture]
  FROM [NORTHWND].[dbo].[Categories] where CategoryID in (1,2,3)

<UserControl x:Class="SilverlightApplication9.MainPage"
    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"
    mc:Ignorable="d" d:DesignHeight="300" d:DesignWidth="400" 
    xmlns:dxe="http://schemas.devexpress.com/winfx/2008/xaml/editors" xmlns:sdk="http://schemas.microsoft.com/winfx/2006/xaml/presentation/sdk">

    <Grid x:Name="LayoutRoot" Background="White">
        <dxe:ComboBoxEdit HorizontalAlignment="Left" Margin="40,246,0,0" Name="comboBoxEdit1" VerticalAlignment="Top" 
                          Width="283" >
            <dxe:ComboBoxEdit.StyleSettings>
                <dxe:CheckedComboBoxStyleSettings />
            </dxe:ComboBoxEdit.StyleSettings>
            <dxe:ComboBoxEdit.Items>
                <dxe:ComboBoxEditItem>Item#1</dxe:ComboBoxEditItem>
                <dxe:ComboBoxEditItem>Item#2</dxe:ComboBoxEditItem>
                <dxe:ComboBoxEditItem>Item#3</dxe:ComboBoxEditItem>
                <dxe:ComboBoxEditItem>Item#4</dxe:ComboBoxEditItem>
            </dxe:ComboBoxEdit.Items>
        </dxe:ComboBoxEdit>
        <dxe:ListBoxEdit Height="200" HorizontalAlignment="Left" Margin="41,47,0,0" Name="listBoxEdit1" 
                         VerticalAlignment="Top" Width="283" SelectionMode="Multiple">
            <dxe:ListBoxEdit.Items>
                <dxe:ListBoxEditItem Content="Item#1" />
                <dxe:ListBoxEditItem Content="Item#3" />
            </dxe:ListBoxEdit.Items>
        </dxe:ListBoxEdit>
        <Button Content="Выбрать данные из ListBox" Height="23" HorizontalAlignment="Left" 
                Margin="40,12,0,0" Name="button1" VerticalAlignment="Top" Width="179" Click="button1_Click" />
        <sdk:Label Height="23" HorizontalAlignment="Left" Margin="232,12,0,0" Name="label1" VerticalAlignment="Top" Width="156" />
    </Grid>
</UserControl>

for (int i = 0; i < list_otdel.Items.Count; i++)
           {
            eform_sampling_Result record_list_Inst = list_otdel.Items[i] as eform_sampling_Result;
            if (record_list_Inst != null)
            {
           z_otdelDomainDataSource.Load();
           var record_Inst = ResourceWrapper.CurrentDomainContext.z_otdel_proc_Results.FirstOrDefault(r => r.indx ==record_list_Inst.eform);
           comboBoxOtdel.SelectedItem = record_Inst;
            }
         }

comboBoxOtdel.SelectedItems.Clear();
for (int i = 0; i < list_otdel.Items.Count; i++)
           {
            eform_sampling_Result record_list_Inst = list_otdel.Items[i] as eform_sampling_Result;
            if (record_list_Inst != null)
            {
           z_otdelDomainDataSource.Load();
           var record_Inst = ResourceWrapper.CurrentDomainContext.z_otdel_proc_Results.FirstOrDefault(r => r.indx ==record_list_Inst.eform);
           comboBoxOtdel.SelectedItems.Add(record_Inst);
            }
         }