combobox windows phone 8.1 no dropdown - xaml

Question

I add a ComboBox in XAML for Windows Phone 8.1 in a StackPanel. On Running the app in the Emulator no Dropdown functionality is shown. If I Limit the StackPanel to a Height e.g. "70", only the 2 first Items are shown. If I say Height = "Auto" then all Items are shown immediately.
How can I enable the Dropdown functionality?
Header:
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
Combobox ..
<StackPanel Grid.Row="4" Width="350" HorizontalAlignment="Left">
<TextBlock x:Name="PlayerListPanel" TextWrapping="Wrap" Text="Select a Player" VerticalAlignment="Center" Margin="2,0,0,0" HorizontalAlignment="Left"/>
<ComboBox Name="StartPlayerComboBox" BorderThickness="1" >
<ComboBoxItem Tag="PLAYER1">Player 1</ComboBoxItem>
<ComboBoxItem Tag="PLAYER2">Player 2</ComboBoxItem>
<ComboBoxItem Tag="PLAYER3">Player 3</ComboBoxItem>
<ComboBoxItem Tag="Dummy1">1</ComboBoxItem>
<ComboBoxItem Tag="Dummy2">2</ComboBoxItem>
<ComboBoxItem Tag="Dummy3">3</ComboBoxItem>
</ComboBox>
</StackPanel>

Answer 1

Try LISTPICKER control..Its functions similar as ComboBox with Auto adjusting height and width..
<toolkit:ListPicker>
<toolkit:ListPickerItem Content="A+" />
<toolkit:ListPickerItem Content="B+" />
<toolkit:ListPickerItem Content="O+" />
</toolkit:ListPicker>
to use this Include following namespace in Xaml Page..ADD windows phone toolkit(click it)
xmlns:toolkit="clr-namespace:Microsoft.Phone.Controls;
assembly=Microsoft.Phone.Controls.Toolkit"
if further info requires... revert back...

Answer 2

You should provide enough height for the combobox to open properly. If you limit the height, the combobox cannot extend beyond that. So it will show only a few items. Height = "Auto" means it can take whatever height as required by it. Thus the combobox will take the height required for it to open properly.

Answer 3

Combobox is Windows Phone/ Windows RunTime Environment behaves differently from its Silverlight/WPF Counterparts. Here we don't have Popup to show the List of items to be selected. Hence the dropdown needs enough space to show the options.
Best thing is to leave the Height as Auto, or MinWidth for any Width requirements.

Answer 4

Even tho, this is an old question, in addition to what they have said, already; a way to have an item selected as the default, you need to "mark it" as follow:
<ComboBoxItem IsSelected="True">Item 1</ComboBoxItem>
Then, once you click on it, you will have all other combo box items displayed (if you define them):
<ComboBox x:Name="myComboBox" VerticalAlignment="Top" Width="350" FontFamily="open sans" FontSize="20" Height="Auto" Foreground="DarkGray" BorderBrush="Black">
<ComboBoxItem IsSelected="True">Item 1</ComboBoxItem>
<ComboBoxItem>Item 2</ComboBoxItem>
<ComboBoxItem>Item 3</ComboBoxItem>
<ComboBoxItem>Item 4</ComboBoxItem>
</ComboBox>
Hope it helps someone. Regards