下拉框

<TextBlock VerticalAlignment="Center">直接在XAML中绑定数据</TextBlock>
        <ComboBox Grid.Column="1" Height="23" Name="cmb1" SelectionChanged="cmb1_SelectionChanged">
            <ComboBoxItem Content="上海" Tag="1"></ComboBoxItem>
            <ComboBoxItem Content="北京" Tag="2"></ComboBoxItem>
            <ComboBoxItem Content="天津" Tag="3"></ComboBoxItem>
        </ComboBox>