在ListView中绑定Combobox

Question

我在ListView中有一个可以绑定到itemsource的组合框。在组合框中选择一个值时，我的选定项目未设置。有人可以告诉我为什么我的选定项目（NumberOfIterations）没有设置？当我将它移到ListView之外时，组合框工作，让我觉得我没有完全正确的绑定，但我无法弄清楚出了什么问题。我使用SimpleMVVMToolkit框架。

<ListView Grid.Row="1" Grid.Column="2" 
    ItemsSource="{Binding SequenceListItems}" 
    SelectedItem="{Binding SequenceListItemSelected}" 
    ItemContainerStyle="{StaticResource alternatingListViewItemStyle}" 
    AlternationCount="2">
<ListView.View>
    <GridView>
        <GridViewColumn Header="# of Iterations" Width="125">
            <GridViewColumn.CellTemplate>
                <DataTemplate>
                    <StackPanel>
                        <ComboBox ItemsSource="{Binding
SequenceEditorViewModel.Iterations, Source={StaticResource ViewModelLocator}}" 
SelectedItem="{Binding Path=NumberOfIterations, Mode=TwoWay}" SelectedIndex="0" 
FontWeight="Bold" VerticalAlignment="Center" Width="60" />
                    </StackPanel>
                </DataTemplate>
            </GridViewColumn.CellTemplate>
        </GridViewColumn>
    </GridView>
</ListView.View>
</ListView>

ViewModel Items ...我目前没有使用模型

// Constructor
public SequenceEditorViewModel()
{
    // Populate the Iterations for displaying in the combobox in the gridview.
    for (int x = 1; x <= 50; x++)
    {
        this.Iterations.Add(x);
    }
}

//public property (Iterations is source for combobox and NumberOfIterations 
//is for the selected item in the combobox)
public ObservableCollection<int> Iterations
{
    get
    {
        return this.iterations;
    }

    set
    {
        this.iterations = value;

        this.NotifyPropertyChanged(m => m.Iterations);
    }
}

public int NumberOfIterations
{
    get
    {
        return this.numberOfIterations;
    }

    set
    {
        this.numberOfIterations = value;

        this.NotifyPropertyChanged(m => m.NumberOfIterations);
    }
}