2 related comboboxes in wpf DataGrid MVVM

Question

Does anyone have an example of binding a 2 related ComboBoxs to a Selected Item of a DataGrid? I have tried, but I can't seem to get it to work. I am fairly new to MVVM so I am doing something wrong.

I have a datagrid which is binded to a collection in an object named NewClient in my ViewModel ClientMarketCodes. ClientMarketCodes has a navigation property named MarketCodeTypes which has a Market Navigation property. so I want to show in the datagrid the code,MarketCodeTyeName,MarketName. I have Managed to show Markets and MarketCodeTypes in DataGrid comboboxes, but I want to do a relation between Markets and MaketCodeTypes where user can only select MarketCodeTypes related to there Market. I have added a selected item to Markets Combobox where on changing it excute filling method of MarketCodeTypes collection binded to MarketCodeTypes Combobox but it doesnt work correctly as the filter applys to all rows of MarketCodetypes Combobox column. I have something that happens in both combobox for example on changing the Markets of one row the combobox shows all other markets I choosed one other Market and click the row is not affected and returns back to its original Market.i dont know why this happens.

Heres my ViewModel:

public class MarketsViewModel : ObservableObject, IMarketsViewModel, INavigationAware, IConfirmNavigationRequest, IRegionMemberLifetime
{
    #region MarketsViewModel

    public MarketsViewModel()
    {
        //NewClient.ClientMarketCodes[0].MarketCodeType.MarketID
        //MarketCodeTypes = new ObservableCollection<MarketCodeType>();
        this.GetMarkets();
        //this.GetMarketCodeTypes();
        this.PropertyChanged += MarketssViewModel_PropertyChanged;
    }

    private void MarketssViewModel_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
    {
        switch (e.PropertyName)
        {
            case "selectedMarket":
            {
                if (selectedMarket != null)
                {
                    GetMarketCodeTypes();
                }

                break;
            }
        }
    }

    #endregion

    #region --Members--

    private ObservableCollection<Market> m_Market;
    private ObservableCollection<MarketCodeType> m_MarketCodeType;
    private List<MarketCodeType> m_MarketCodeTypes;

    public List<MarketCodeType> MarketCodeTypesList
    {
        get
        {
            if (m_MarketCodeTypes == null)
            {
                m_MarketCodeTypes = new List<MarketCodeType>();
            }

            return m_MarketCodeTypes;
        }
        set
        { 
            m_MarketCodeTypes = value;

            RaisePropertyChanged("MarketCodeTypesList");
            RaisePropertyChanged("MarketCodeTypes");
        }
    }

    public ObservableCollection<MarketCodeType> MarketCodeTypes
    {
        get
        {
            if (MarketCodeTypesList != null)
                return new ObservableCollection<MarketCodeType>(MarketCodeTypesList);
            else
                return new ObservableCollection<MarketCodeType>();
        }
    }

    #endregion

    #region --Properties--

    public ObservableCollection<Market> Markets
    {
        get { return m_Market; }
        set
        {
            m_Market = value;
            RaisePropertyChanged("Markets");
        }
    }

    private Market _selectedMarket;
    public Market selectedMarket
    {
        get { return _selectedMarket; }
        set
        {
            if (_selectedMarket != value)
            {
                _selectedMarket = value;
                RaisePropertyChanged("selectedMarket");
                RaisePropertyChanged("MarketCodeTypes");
            }
        }
    }

    #endregion

    private void GetMarkets()
    {
        try
        {
            Market[] MarketArr;

            using (var client = new ClientServiceProxy())
            {
                MarketArr = client.GetAllMarkets();
            }
            if (MarketArr != null)
            {
                this.Markets = new ObservableCollection<Market>(MarketArr);
            }
        }
        catch (Exception e)
        {
            MessageBox.Show(e.Message);
        }
    }

    private void GetMarketCodeTypes()
    {
        try
        {
            MarketCodeType[] MarketCodeTypeArr;
            using (var client = new ClientServiceProxy())
            {
                MarketCodeTypeArr = client.GetAllMarketCodeTypes().Where(c=>c.MarketID==selectedMarket.marketID).ToArray();
            }
            if (MarketCodeTypeArr != null)
            {
                MarketCodeTypesList = MarketCodeTypeArr.ToList();
            }
            else
            { MarketCodeTypesList = new List<MarketCodeType>(); }

        }
        catch (Exception e)
        {
            MessageBox.Show(e.Message);
        }
    }
}`

Here's My Xaml:

 <Grid x:Name="grid2" RenderTransformOrigin="0.5,0.5">

        <Custom:C1DataGrid x:Name="c1DataGrid"  
                           AutoGenerateColumns="False"
                           Height="490"  
                           ItemsSource="{Binding Path=NewClient.ClientMarketCodes,Mode=TwoWay,UpdateSourceTrigger=LostFocus,ValidatesOnDataErrors=True,ValidatesOnExceptions=True}">
                <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
                    <GradientStop Color="#FFBEBE00" Offset="0.5"/>
                    <GradientStop Color="#FFEDED9A" Offset="0.496"/>
                </LinearGradientBrush>
            </Custom:C1DataGrid.HeaderBackground>
            <Custom:C1DataGrid.Columns>
                <!--<Custom:DataGridCheckBoxColumn  Header="???? ?????"/>-->
                <Custom:DataGridTextColumn Header="Code" Binding="{Binding Code,Mode=TwoWay}" IsReadOnly="False"  />

                <Custom:DataGridTemplateColumn Header="MarketCodeType" >
                    <Custom:DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <TextBlock Text="{Binding MarketCodeType.NameA}"/>
                        </DataTemplate>
                    </Custom:DataGridTemplateColumn.CellTemplate>
                    <Custom:DataGridTemplateColumn.CellEditingTemplate>
                        <DataTemplate>
                          <ComboBox  Name="cmbMarketCodeTypes" 
                                                 ItemsSource="{Binding RelativeSource={RelativeSource FindAncestor,AncestorType=my:MarketsView},Path=DataContext.MarketCodeTypes}" 
                                                 DisplayMemberPath="NameA" 
                                                 SelectedValue="{Binding Path=MarketCodeTypeID,Mode=TwoWay,ValidatesOnDataErrors=True}" 
                                                />
                        </DataTemplate>
                    </Custom:DataGridTemplateColumn.CellEditingTemplate>
                </Custom:DataGridTemplateColumn>

                <Custom:DataGridTemplateColumn Header="Markets">
                    <Custom:DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <TextBlock Text="{Binding MarketCodeType.Market.NameA}"/>
                        </DataTemplate>
                    </Custom:DataGridTemplateColumn.CellTemplate>
                    <Custom:DataGridTemplateColumn.CellEditingTemplate>
                        <DataTemplate>
                            <ComboBox Name="cmbMarkets" ItemsSource= "{Binding RelativeSource={RelativeSource FindAncestor,AncestorType=my:MarketsView},Path=DataContext.Markets,Mode=TwoWay}" 
  DisplayMemberPath="NameA" SelectedValue="{Binding Path=MarketCodeType.Market.MarketID,Mode=TwoWay}" 
                SelectedValuePath="MarketCodeType.MarketID"
       SelectedItem="{Binding RelativeSource={RelativeSource FindAncestor,AncestorType=my:MarketsView},Path=DataContext.selectedMarket,Mode=TwoWay}"    />
                        </DataTemplate>
                    </Custom:DataGridTemplateColumn.CellEditingTemplate>
                </Custom:DataGridTemplateColumn> 


                </Custom:DataGridTemplateColumn>
            </Custom:C1DataGrid.Columns>

        </Custom:C1DataGrid>