Add Control programmatically, UI is not updating

Question

I am just playing arround with .Net MAUI. I want to retrieve information from a Rest service and based on the result I want to add Buttons programmatically to a VerticalStackLayout. When I debug the solution the buttons are added to the VerticalStackLayout but the UI is not updated.

Here the code Snippet

var btn = new Button(); btn.Text = "Button " + count + " added"; btn.Clicked += OnCounterClicked; btn.HorizontalOptions = LayoutOptions.Center; VLayout.Add(btn);

Here the XAML

<ScrollView> <VerticalStackLayout x:Name="VLayout" Spacing="25" Padding="30,0" VerticalOptions="Center"> <Image Source="dotnet_bot.png" SemanticProperties.Description="Cute dot net bot waving hi to you!" HeightRequest="200" HorizontalOptions="Center" /> <Label Text="Hello, World!" SemanticProperties.HeadingLevel="Level1" FontSize="32" HorizontalOptions="Center" /> <Label Text="Welcome to .NET Multi-platform App UI" SemanticProperties.HeadingLevel="Level2" SemanticProperties.Description="Welcome to dot net Multi platform App U I" FontSize="18" HorizontalOptions="Center" /> <Entry x:Name="entry" Placeholder="Enter text" TextChanged="OnTextChanged" Completed="OnTextCompleted" /> <Button x:Name="KommenBtn" Text="Kommen" SemanticProperties.Hint="Counts the number of times you click" Clicked="OnCounterClicked" HorizontalOptions="Center" /> <Button x:Name="GehenBtn" Text="Gehen" SemanticProperties.Hint="Counts the number of times you click" Clicked="OnCounterClicked" HorizontalOptions="Center" /> </VerticalStackLayout> </ScrollView>

ToolmakerSteve · Accepted Answer · 2022-07-31 18:51:10Z

To update UI after a change that affects the hierarchy (or positions) of controls:

 (VLayout as IView).InvalidateArrange();

NOTE: This is roughly equivalent to Xamarin.Forms layout.ForceLayout();

If not already in code running on UI MainThread, wrap it in Dispatch:

Dispatcher.Dispatch(() => (VLayout as IView).InvalidateArrange());

Hello, thanks for your answer!! Unfortunately the bevahior still stays the same, UI isn't updated. Do you have an additional hint? thanks in advance & BW

ColeX · Accepted Answer · 2022-05-27 05:45:23Z

Try to update UI on main thread , you can wrap your code into Application.Current.Dispatcher.Dispatch .

Sample code

Application.Current.Dispatcher.Dispatch(() => { var btn = new Button(); btn.Text = "Button " + count + " added"; btn.Clicked += OnCounterClicked; btn.HorizontalOptions = LayoutOptions.Center; VLayout.Add(btn); });

Collectives™ on Stack Overflow

Add Control programmatically, UI is not updating

2 Answers 2

1 Comment

Sample code

Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Sample code

Comments

Linked

Related