WPF pre-render a list w/o actually showing it - wpf

Question

Is there a way to "pre-render" a list in WPF without actually showing it to the user? I have a list that renders fairly slowly ( a few seconds ) the first time it is displayed to the user.
I'd like to pre-render/pre-draw the list so that the few seconds it takes to display the list to the users is not noticeable. I'd like this to happen while the app is starting up - while my splash screen is displayed.
What is the best way to accomplish this?
EDIT:
Here is my list item style. As you can see the target type is a Button. The button also has a RoutedEvent (Command) set on it.
<Style x:Key="Button_ProductFinder_Item" TargetType="Button">
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate TargetType="Button">
<Grid Width="690" Height="181" >
<Image Name="Up" Source="{StaticResource Img_ProductFinder_FriendUp}" Stretch="Uniform"/>
<Image Name="Down" Source="{StaticResource Img_ProductFinder_FriendDn}" Visibility="Hidden" Stretch="Uniform"/>
<Canvas Name="Clip" ClipToBounds="True" Height="162" Width="175" HorizontalAlignment="Left" Margin="0,10,0,0" >
<Image Name="DynamicFriend" Stretch="UniformToFill" Canvas.Left="16" Canvas.Top="-10" HorizontalAlignment="Left" Source="{Binding ImageSource}" Height="162" Width="162" />
<Canvas.RenderTransform>
<TransformGroup>
<TranslateTransform />
</TransformGroup>
</Canvas.RenderTransform>
</Canvas>
<TextBlock Name="DynamicName" Margin="210,69,0,0" Style="{StaticResource ButtonFriend_Textstyle}"
TextWrapping="Wrap" HorizontalAlignment="Left" Width="440" VerticalAlignment="Stretch" Height="Auto"
Text="{Binding ProductName}" />
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="IsPressed" Value="True">
<Setter TargetName="Up" Property="Visibility" Value="Hidden"/>
<Setter TargetName="Down" Property="Visibility" Value="Visible"/>
<Setter TargetName="Clip" Property="RenderTransform">
<Setter.Value>
<TransformGroup>
<TranslateTransform Y="2"/>
</TransformGroup>
</Setter.Value>
</Setter>
<Setter TargetName="DynamicName" Property="RenderTransform">
<Setter.Value>
<TransformGroup>
<TranslateTransform Y="2"/>
</TransformGroup>
</Setter.Value>
</Setter>
<Setter TargetName="DynamicName" Property="Foreground" Value="#FFFFFF"/>
<Trigger.EnterActions>
<ctrls:ButtonSoundPlayerAction SoundFile="buttonclick.wav"/>
</Trigger.EnterActions>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>

Answer 1

Check WHAT is slow. Really. Itf it is like the db filling up the list, your question is totally off (as the perforamnce is not WPF realted).
How large is the list? I have a list of 5000 elements rendering in a moments notice. Mosty because my 4.0 virtual list only renders what is on the list. You are not data bound while fillng up the list, or?
Finally, what is slow in the rndering? Use a wpf profiler to find out and tell us - because at the nd of the day you may simply try to optimize the wrong thing.

Answer 2

You could always set the list (or the whole window the list is contained in) to collapsed in it's initial state, and then un-collapse it when you get word back from your data retrieval thread that it is done.
I have done that with a couple of my other programs and it works pretty well.
User executes the program, splash screen displays, and main window loads collapsed.
Data retrieval thread executes, gets data, reports it is finished.
Splash screen disappears, main window displays and list is populated.