I am trying to show a header in my collectionview with this code (which im sure would work on xamarin)
<CollectionView SelectionMode="Multiple"
SelectionChanged="collectionview_coll_skills_SelectionChanged"
Margin="5,0,0,0"
EmptyView="{x:Static res:Strings.LaedtSKills}"
Grid.Row="0"
VerticalScrollBarVisibility="Never" x:Name="collectionview_coll_skills">
<CollectionView.HeaderTemplate>
<DataTemplate>
<ViewCell>
<ContentView>
<Label Text="Hi mom"/>
</ContentView>
</ViewCell>
</DataTemplate>
</CollectionView.HeaderTemplate>
The text "hi mom" is just not shown at all,
if I however inserted the text directly into the property (eg Header="hi mom")
It would be displayed but then no layoutting is possible.
Anyone already found a fix or workaround for this?
Thanks
As posted in my comment you can just use the Header of the CollectionView
You can style it as needed. More Info Microsoft Header/Footer resource
<CollectionView.Header>
<Label Text="Hi mom" />
</CollectionView.Header>
I am working on a MAUI app, which has a page with two ListViews. Only one should be visible at a time, which i do by setting their IsVisible property to true or false. Upon switching from one to the other, the app freezes or becomes extremely slow. I suppose this is because the listview's itemssource is rather large. I bound both listviews to an observablecollection, which should be the fastest option. Both ObservableCollections have data that updates rather often, and both should get quite big (1000+ items).
How can I optimize the listviews to load quickly?
I have tried to limit the itemssource to a certain amount of objects, but this only makes it slower. I guess this is because removing items from the itemssource in a first-in-first-out way basically updates every single object within the obervablecollection.
My current code:
`
<Grid RowDefinitions="*,5,40" ColumnDefinitions="75,75,75,105,*">
<ScrollView x:Name="SerialLogScrollViewASCII"
Grid.ColumnSpan="6"
VerticalScrollBarVisibility="Always"
Grid.Row="0"
IsVisible="{Binding IsASCIILogVisible}"
BackgroundColor="Transparent">
<ListView x:Name="LogStackASCII"
ItemsSource="{Binding SerialLogASCII}"
BackgroundColor="Transparent"
ItemTapped="LogMessageTapped"
SelectionMode="Single">
<ListView.ItemTemplate>
<DataTemplate >
<ViewCell>
<Grid PropertyChanged="SerialLogChanged" ColumnDefinitions="160,*" ColumnSpacing="5" BackgroundColor="Transparent">
<Label Text="{Binding Time}" Margin="0,0,10,0" Grid.Column="0" FontSize="12" BackgroundColor="Transparent"/>
<Label Text="{Binding Message}" LineBreakMode="CharacterWrap" Grid.Column="1" FontSize="12" BackgroundColor="Transparent"/>
</Grid>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</ScrollView>
<ScrollView x:Name="SerialLogScrollViewHEX"
Grid.ColumnSpan="6"
VerticalScrollBarVisibility="Always"
Grid.Row="0"
IsVisible="{Binding IsHEXLogVisible}"
BackgroundColor="Transparent">
<ListView x:Name="LogStackHEX"
ItemsSource="{Binding SerialLogHEX}"
BackgroundColor="Transparent"
ItemTapped="LogMessageTapped"
SelectionMode="Single">
<ListView.ItemTemplate>
<DataTemplate >
<ViewCell>
<Grid PropertyChanged="SerialLogChanged" Padding="1" ColumnDefinitions="160,*" ColumnSpacing="5" BackgroundColor="Transparent">
<Label Text="{Binding Time}" Margin="0,0,10,0" Grid.Column="0" FontSize="12" BackgroundColor="Transparent"/>
<Label Text="{Binding Message}" LineBreakMode="CharacterWrap" Grid.Column="1" FontSize="12" BackgroundColor="Transparent"/>
</Grid>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</ScrollView>
</Grid>
`
When you put Vertical ListView, inside Vertical ScrollView, the performance is pretty much non-existent. The more and more items you add, the worse it will get.
You should not be doing this. ListView has its own scroll.
Consider CollectionView or DataGrid.
First remove the scolls. Then if you are not happy, try CollectionView or DataGrid.
And then if you have questions, please ask.
Edit: Last attempt to explain this.
Putting a ListView or CollectionView or ANY container that has variable height, inside Vertical ScrollView or Vertical StackLayout or ANY container that is not limiting the height, makes the first container GROW in height until all the content is loaded.
This means, if you have 100 000 items, all of them will be loaded in the inner container.
This "programmatically scrolling works better" is actually the result of pre-loading everything, and it is not better for the performance, it is plain and simple killing it.
Try adding 100, 1000, 10000, 100000 items, and you will see how it gets progressively worse.
Containers of other VisualElements (Like ListView or CollectionView) have built-in design patterns to handle displaying them in portions. When and if displaying of that item is needed.
You could try Caching strategy in ListView. Try the following code
<ListView x:Name="LogStackASCII" CachingStrategy="RecycleElement"
...
RecycleElement should be used in the following circumstances:
Each cell has a small to moderate number of bindings.
Each cell's BindingContext defines all of the cell data.
Each cell is largely similar, with the cell template unchanging.
I found the Xamarin official docs ListView performance for you. It also works for Maui. Besides the Caching strategy, it also gives some other ListView performance suggestions to enhance performance of Listview.
By the way, the two ListView almost have the same template, so why not just use one ListView? And when switching, just change the itemsSource it binds to.
Hope it works for you.
Im buildining a novel-manga app.
When i came to novels there was about 2000 chapthers and i need to render them all at once.
Im using a listview to render them but its to damnt slow.
I was wondering if there is a faster solution like a renderer or somthing i could build that will work faster.
Here is my current XAML
<ListView ItemsSource="{Binding Chapters}"
x:Name="grdChapters"
ItemSelected="GrdChapters_ItemSelected">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<StackLayout Padding="5" HeightRequest="30">
<StackLayout Orientation="Horizontal">
<Label TextColor="Black" Text="{Binding Name}" VerticalOptions="Center" HorizontalOptions="StartAndExpand" Style="{StaticResource header}" FontAttributes="None" />
<Image Source="right.png" HorizontalOptions="End" IsVisible="{Binding Completed}" WidthRequest="16" HeightRequest="16" Aspect="AspectFit" />
</StackLayout>
<BoxView Style="{StaticResource lightLine}" />
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
The RecycleElementAndDataTemplate should improve your performance, because even though you're not using any dynamic images, the datatamplate is the same for all of the items in the list and it'll get optimized.
If that doesn't help, I'd recommend using the glidex library for Xamarin.Android, it makes scrolling a lot smoother.
My issue is when I add in labels to my ListView they wont show.
I am binding the labels to objects inside "DummyClass". FirstName, LastName, RepId.
I have done plenty amount of research over this issue and have asked multiple people to help on this subject but nothingenter image description here seems to work.
<StackLayout>
<ListView x:Name="listView"
HeightRequest="100">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<StackLayout>
<Label Text="Hello"
BackgroundColor="Red"
VerticalOptions="FillAndExpand"/>
<Label Text="Yes"
BackgroundColor="Red"
VerticalOptions="FillAndExpand"/>
<Label Text="Wooohooo"
BackgroundColor="Red"
VerticalOptions="FillAndExpand"/>
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</StackLayout>
I found out what my issue was. It was the ItemSource. My ItemSource was not defined correctly. Fixed all the issues I was having. Thank you all for helping!
I'm attempting to data bind a list of information to a ListView in Xamarin.forms, but I'm having issues because of how it is indexed. I need to get the string of information found in sortedList[0].Info[multiple indexes].CoverLink to display on my Image element inside of my Xamarin app, but I'm not sure how to go about it. My Xaml file is as follows:
<ListView RowHeight="100" x:Name="PinnedListView">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<StackLayout Orientation="Horizontal" HorizontalOptions="Start">
<Image Source="{Binding CoverLink}" HeightRequest="100"/>
<StackLayout Orientation="Vertical">
<Label Text="{Binding ID}"/>
<Label Text="{Binding SomeOtherBinding}"/>
</StackLayout>
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
and I'm assigning the ItemSource via c# by stating:
PinnedListView.ItemsSource = sortedList;
Here is a screenshot of my list architecture:
How to data bind it? Thanks.
you need to specify which element of the Info array you want to use
<Image Source="{Binding Info[0].CoverLink}" HeightRequest="100"/>
As you can see, the CoverLink is in the Infonested array, so, in order to access to it try this:
<Image Source="{Binding Info[0].CoverLink}" HeightRequest="100"/>