WPF 中combox与datagrid绑定

<Grid x:Name="LayoutRoot"  DataContext="{Binding Source={StaticResource Locator}, Path=CustomerViewModel}">
        <Grid.RowDefinitions>
            <RowDefinition Height="50"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>
        <StackPanel Margin="20,0,0,0" VerticalAlignment="Center" Orientation="Horizontal">
            <Label Content="新客户："/>
            <TextBox TextWrapping="Wrap" Width="142" Margin="0,0,10,0" Name="txt_name" />
            <Label Content="客户类型："/>
            <ComboBox Width="120" Margin="0,0,20,0" Name="comb_type" ItemsSource="{Binding GetCustomType,Mode=OneWay}" DisplayMemberPath="Name" SelectedValuePath="Id" />
            <Button Content="添 加" Width="75" Name="bt_add" />
        </StackPanel>
        <DataGrid Margin="0" Grid.Row="1" Name="dg_list" ItemsSource="{Binding GetCustomers}" AutoGenerateColumns="False" IsReadOnly="True"  >
         <DataGrid.Columns>
          <DataGridTextColumn Binding="{Binding Id,Mode=OneWay}" Header="编号" Visibility="Hidden"/>
          <DataGridTextColumn Binding="{Binding Name,Mode=OneWay}" Header="客户名称" Width="100"/>
          <DataGridTextColumn Binding="{Binding CustomType.Name,Mode=OneWay}" Header="客户类型" Width="150"/>
          <DataGridTextColumn Binding="{Binding CreateTime.Date, Mode=OneWay}" Header="创建时间"/>
         </DataGrid.Columns>
        </DataGrid>
    </Grid>