PDFOffice_Windows_exe/PDF Office/CustomControl/Form/FormFieldCombox.xaml

<UserControl
    x:Class="PDF_Office.CustomControl.Form.FormFieldCombox"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:local="clr-namespace:PDF_Office.CustomControl.Form"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    d:DesignHeight="450"
    d:DesignWidth="800"
    mc:Ignorable="d">
    <ComboBox
        Name="Combox"
        VerticalContentAlignment="Center"
        SelectedIndex="0"
        SelectionChanged="Combox_SelectionChanged" />
</UserControl>