WPF Extended Toolkit Control in Custom Control not pulling through to form?

Question

I am using the Xceed Extended WPF Toolkit for the Integer Up Down Control. I have installed this via Nuget.

I have the integrated into a custom control which contains other normal textboxes and button etc.

This custom control I then put in a tab control on a Window. Everything shows correctly apart from this IntegerUpDown which shows as an empty box. (It is fine when looking at the custom control in design)

I have added the namespace to both the control and window so am not sure what the problem is. Everything is inside one project so I don't think references are a problem.

Any ideas of what I could be missing?

Control XAML:

<Label Grid.Row="3" Content="Quantity of Tickets:" VerticalAlignment="Center"></Label>
<xctk:IntegerUpDown Grid.Row="3" Grid.Column="1" Name="numTickets"></xctk:IntegerUpDown>

Form XAML:

<TabItem Header="New Booking">
      <Grid Background="#FFE5E5E5">
           <btc:NewBooking></btc:NewBooking>
      </Grid>
 </TabItem>

Thanks, Ryan

Answer 1

Here's a MCVE:

MainWindow:

<Window
    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:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:local="clr-namespace:WpfApplication8"
    x:Class="WpfApplication8.MainWindow"
    mc:Ignorable="d"
    Title="MainWindow" Height="300" Width="300">
<Grid>
    <TabControl x:Name="tabControl" Margin="0">
        <TabItem Header="TabItem 1">
            <Grid Background="#FFE5E5E5">
                <local:UserControl1></local:UserControl1>
            </Grid>
        </TabItem>
        <TabItem Header="TabItem 2">
            <Grid Background="#FFE5E5E5"/>
        </TabItem>
    </TabControl>
</Grid>

UserControl:

<UserControl x:Class="WpfApplication8.UserControl1"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
         xmlns:xctk="http://schemas.xceed.com/wpf/xaml/toolkit" 
         xmlns:local="clr-namespace:WpfApplication8"
         mc:Ignorable="d" 
         d:DesignHeight="300" d:DesignWidth="300">
<Grid>
    <StackPanel>
        <Label Grid.Row="3" Content="Quantity of Tickets:" VerticalAlignment="Center"></Label>
        <xctk:IntegerUpDown Grid.Row="3" Grid.Column="1" Name="numTickets"></xctk:IntegerUpDown>
    </StackPanel>
</Grid>

Both MainWindow and UserControl are at the same level in the project structure:

---

EDIT: One more thing, make sure your UserControl is fully contained by the MainWindow and you do NOT have something like this:

That would cause the IntegerUpDown look like an empty box, like you described.