In WPF, I want to dynamically set the itemsource based on combo box selection

I have a Slider and a Combobox in my view. I have 2 properties in my ViewModel. Based on the selection of the combobox, I want to bind any one of the property to the value of the slider.

 private int _xValue;

    public int XValue
    {
        get { return _xValue; }
        set
        {
            _xValue = value;
            NotifyPropertyChanged();
        }
    }

    private int _yValue;

    public int YValue
    {
        get { return _yValue; }
        set
        {
            _yValue = value;
            NotifyPropertyChanged();
        }
    }

 <StackPanel>
     <ComboBox SelectedIndex="0" Margin="2" Width="100">
        <ComboBoxItem Tag="X">X</ComboBoxItem>
        <ComboBoxItem Tag="Y">Y</ComboBoxItem>
    </ComboBox>

    <Slider Value="{Binding XValue}"></Slider>
</StackPanel>

I want to bind the Slider value to XValue or YValue depending on the selection of the ComboBox

You could use a Style with a DataTrigger that binds to the SelectedItem of the ComboBox:

<ComboBox x:Name="cmb" SelectedIndex="0" Margin="2" Width="100">
    <ComboBoxItem Tag="X">X</ComboBoxItem>
    <ComboBoxItem Tag="Y">Y</ComboBoxItem>
</ComboBox>

<Slider>
    <Slider.Style>
        <Style TargetType="Slider">
            <Setter Property="Value" Value="{Binding XValue}" />
            <Style.Triggers>
                <DataTrigger Binding="{Binding SelectedItem.Tag, ElementName=cmb}" Value="Y">
                    <Setter Property="Value" Value="{Binding YValue}" />
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </Slider.Style>
</Slider>