Slow perforamce after refresh

[Erdei László]

Hello.

When i use listView.DataSource.Refresh() or listView.DataSource.RefreshFilter() the whole app bacame really slow on IOS. Scrolling take more then 3 sec. Android is ok. 

Latest VS 19 and every package up to date.

Some code for refreshfilter: 

        private void OnFilterTextChanged(object sender, TextChangedEventArgs e)

        {

            searchBar = (sender as SearchBar);

            if (listView.DataSource != null)

            {

                listView.DataSource.Filter = FilterContacts;

                listView.DataSource.RefreshFilter();  //Whitout this line the app keep fast, but search not working

                listView.ScrollTo(0);

                

            }

        }

        private bool FilterContacts(object obj)

        {

            if (searchBar == null || searchBar.Text == null)

            {

                return true;

            }

            PhonebookEntry contacts = obj as PhonebookEntry;

            return contacts.Contain(searchBar.Text.ToLower());

        }

  <Grid>

            <Grid.RowDefinitions>

                <RowDefinition Height="Auto"/>

                <RowDefinition Height="Auto"/>

            </Grid.RowDefinitions>

            <SearchBar x:Name="filterText" HeightRequest="40"  TextChanged="OnFilterTextChanged" Grid.Row="0"/>

            <listview:SfListView x:Name="listView" Grid.Row="1" ItemSize="120" AutoFitMode="DynamicHeight" SelectionMode="Single" SelectionGesture="Tap" SelectionBackgroundColor="Transparent" ItemsSource="{x:Static local:Phonebook.VM}" IsScrollBarVisible="False" Padding="8" ItemSpacing="8" BackgroundColor="Transparent"  AllowSwiping="True"   >

                <listview:SfListView.ItemTemplate>

                    <DataTemplate>

                        <cards:SfCardView CornerRadius="4" HasShadow="True" WidthRequest="343" BackgroundColor="{DynamicResource Gray-White}"   HorizontalOptions="Center" Padding="16,16,8,16">

...

</cards:SfCardView>

                    </DataTemplate>

                </listview:SfListView.ItemTemplate>

            </listview:SfListView>

</Grid>

What i do wrong? 

[Lakshmi Natarajan]

Hi Erdei, 

 

Thank you for using Syncfusion products. 

 

We have checked the reported query “Slow performance after refreshing the ListView” from our end. We would like to inform you that we are unable to reproduce the reported scenario from our side. We have checked our sample based on the code snippets provided in iPhone 11 iOS 13.1 simulator with Syncfusion v18.2.0.55 and Xamarin.Forms 4.8.0.1269. We have attached the tested sample and video in the following link,  

Sample: https://www.syncfusion.com/downloads/support/directtrac/general/ze/SortingFiltering-1590364714 

Video: https://www.syncfusion.com/downloads/support/directtrac/general/ze/ListViewFilterVideo.mov122336273 

 

Please check our sample and let us know if you still facing the same issue? If not, please modify our sample tor reproduce the issue and revert us back with the following details, 

• Share ListView related templates
• Share filter code snippets
• Share device configuration details
• Share issue reproducing video

 

It will be helpful for us to check on it and provide you the solution as soon as possible. 

 

Regards, 

Lakshmi Natarajan