I am developing a WPF app from 2 locations, one has a beefy PC on windows 10, the other has a much older PC with worse hardware, running Windows 7.
on the windows 10 PC, I never notice a problem, this is only reproducible on windows 7 machine.
In my Window, I have a ContentControl which is bound to a UserControl property in the window's viewmodel.
I can show different usercontrols there, and most behave fine. I have 2 however, which when I attempt to load them, they take literally 3-5 seconds, during which the UI thread hangs.
They don't have much going on in xaml, I have more complex stuff in xaml in other controls so I don't think the problem lies there.
The one thing these 2 controls are doing differently, which other controls which don't have this issue aren't doing is in the constructor for the usercontrol in the .xaml.cs file, they set their datacontext.
InitializeComponent();
DataContext = new CreateGroupPanelViewModel();
The contructor for the viewmodel, just sets some properties to values. Mainly some string to string.Empty, instantiates 2 ObservableCollections, sets a bool to true and sets a string to "Create Game".
The first time I open this control, I have the problem but the second time it poses no delay at all. Also, if I run the program for a minute or so and THEN try to open it for the first time it will also be fine.
I cannot understand why instantiating this usercontrol would create such a massive performance hit, or why it would act so differently on the 2 different machines.
EDIT The slowdown occurs within the InitializeComponent(); of the usercontrol.
Here is the XAML of such a control:
<UserControl x:Class="CasinoDB.UserControls.ModifyPanels.UCModifyGamePanel"
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:local="clr-namespace:CasinoDB.UserControls.ModifyPanels"
xmlns:vm="clr-namespace:CasinoDB.ViewModels"
mc:Ignorable="d"
d:DesignHeight="500" d:DesignWidth="300">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition />
</Grid.RowDefinitions>
<TextBlock Grid.Row="0" Text="{Binding Header}" HorizontalAlignment="Center" Margin="5" FontWeight="Bold" FontSize="20" />
<StackPanel Grid.Row="1" HorizontalAlignment="Center">
<StackPanel Orientation="Horizontal" HorizontalAlignment="Center" Margin="5">
<TextBlock Text="Name:" Margin="5" />
<TextBox Text="{Binding Name, UpdateSourceTrigger=PropertyChanged}" Margin="5" MinWidth="150" />
</StackPanel>
<StackPanel Orientation="Horizontal" HorizontalAlignment="Center" Margin="5">
<TextBlock Text="RTP:" Margin="5" />
<TextBox Text="{Binding RTP, UpdateSourceTrigger=PropertyChanged}" Margin="5" MinWidth="50" />
</StackPanel>
<StackPanel Orientation="Horizontal" HorizontalAlignment="Center" Margin="5">
<TextBlock Text="Variance:" Margin="5" />
<TextBox Text="{Binding Variance, UpdateSourceTrigger=PropertyChanged}" Margin="5" MinWidth="150" />
</StackPanel>
<StackPanel Orientation="Horizontal" HorizontalAlignment="Center" Margin="5">
<TextBlock Text="Lines:" Margin="5" />
<TextBox Text="{Binding Lines, UpdateSourceTrigger=PropertyChanged}" Margin="5" MinWidth="100" />
</StackPanel>
<StackPanel Orientation="Horizontal" HorizontalAlignment="Center" Margin="5">
<TextBlock Text="Min Bet:" Margin="5" />
<TextBox Text="{Binding MinBet, UpdateSourceTrigger=PropertyChanged}" Margin="5" MinWidth="50" />
</StackPanel>
<StackPanel Orientation="Horizontal" HorizontalAlignment="Center" Margin="5">
<TextBlock Text="Max Win:" Margin="5" />
<TextBox Text="{Binding MaxWin, UpdateSourceTrigger=PropertyChanged}" Margin="5" MinWidth="75" />
</StackPanel>
<StackPanel Orientation="Horizontal" HorizontalAlignment="Center" Margin="5">
<TextBlock Text="Vendor:" Margin="5" />
<TextBox Text="{Binding Vendor, UpdateSourceTrigger=PropertyChanged}" Margin="5" MinWidth="150" />
</StackPanel>
<StackPanel Orientation="Horizontal" HorizontalAlignment="Center" Margin="5">
<TextBlock Text="Notes:" Margin="5" />
<TextBox Text="{Binding Notes}" Margin="5" Width="250" TextWrapping="Wrap" AcceptsReturn="True" AcceptsTab="True" SpellCheck.IsEnabled="True" Height="75" VerticalScrollBarVisibility="Auto" ScrollViewer.CanContentScroll="True" />
</StackPanel>
<CheckBox Content="Create Another" IsChecked="{Binding CreateAnother}" Margin="5" Visibility="{Binding ShowCreateAnother, Converter={StaticResource BooleanToVisibilityConverter}}" HorizontalAlignment="Center" HorizontalContentAlignment="Center" />
<StackPanel Orientation="Horizontal" HorizontalAlignment="Center" Margin="5">
<Button Content="SAVE" Command="{Binding Save}" Margin="5" Style="{StaticResource ConfirmButton}" />
<Button Content="CLOSE" Command="{Binding Close}" Margin="5" />
</StackPanel>
</StackPanel>
</Grid>
</UserControl>
OK, so after attempting to isolate the issue, I finally found my problem. It lies in SpellCheck.IsEnabled="True" on TextBoxes. I found this by commenting out large sections, testing performance, then uncommenting small amounts until it was acting slow on the machine it acts slow on.
After figuring this was the cause, I found a similar post on SO with information relating to a registry entry being filled up with dictionairies. I don't appear to have an entry in that location in the registry, so maybe my problem was similar, but that it was looking and couldn't find anything at all.
Anyway, I can live without spellcheck in those fields, I'll just remove it.