UWP Listview became very slow while binding massive data - c#

I'm trying to bind data to listview using ObservableCollection.
My XAML is like this
<ScrollViewer x:Name="svListEarthquakes" Grid.Row="2" Grid.ColumnSpan="4" ViewChanged="svListEarthquakes_ViewChanged">
<ListView x:Name="listEarthquakes" IsItemClickEnabled="True" SelectionMode="Single" ItemsSource="{x:Bind ObsList}" ItemClick="listEarthquakes_ItemClick">
<ListView.ItemContainerStyle>
<Style TargetType="ListViewItem">
<Setter Property="HorizontalContentAlignment" Value="Stretch"></Setter>
<Setter Property="BorderBrush" Value="LightGray"></Setter>
<Setter Property="BorderThickness" Value="0,0,0,1"></Setter>
</Style>
</ListView.ItemContainerStyle>
<ListView.ItemTemplate>
<DataTemplate>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="2*"/>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="2*"/>
</Grid.ColumnDefinitions>
<TextBlock Grid.Column="0" TextWrapping="WrapWholeWords" Text="{Binding properties.mag}" VerticalAlignment="Center" HorizontalAlignment="Center"/>
<TextBlock Grid.Column="1" TextWrapping="WrapWholeWords" Text="{Binding Path=properties.time,Converter={StaticResource cvtDate}}" VerticalAlignment="Center" HorizontalAlignment="Center"/>
<TextBlock Grid.Column="2" TextWrapping="WrapWholeWords" Text="{Binding geometry.coordinates[0]}" VerticalAlignment="Center" HorizontalAlignment="Center"/>
<TextBlock Grid.Column="3" TextWrapping="WrapWholeWords" Text="{Binding geometry.coordinates[1]}" VerticalAlignment="Center" HorizontalAlignment="Center"/>
<TextBlock Grid.Column="4" TextWrapping="WrapWholeWords" Text="{Binding geometry.coordinates[2]}" VerticalAlignment="Center" HorizontalAlignment="Center"/>
<TextBlock Grid.Column="5" TextWrapping="WrapWholeWords" Text="{Binding properties.place}" VerticalAlignment="Center" HorizontalAlignment="Center"/>
</Grid>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</ScrollViewer>
and C# code
private async Task DisplayDataAsync()
{
Debug.WriteLine("BeginRequest " + DateTime.Now);
var repsonse = (Application.Current as App).gEarthquakesGeoJson = await HttpEarthquakes.GetdEarthquakesGeoJsonAsync<EarthquakesModel>(strRequestUrl);
if (repsonse.metadata.status == 200)
{
Debug.WriteLine("EndRequest " + DateTime.Now);
Debug.WriteLine("BeginxBind " + DateTime.Now);
Debug.WriteLine("Count " + repsonse.metadata.count);
ObsList.Clear();
if (repsonse.metadata.count > 0)
{
//List<FeaturesItem> fis = new List<FeaturesItem>();
foreach (FeaturesItem em in repsonse.features)
{
FeaturesItem fi = new FeaturesItem
{
type = em.type,
properties = em.properties,
geometry = em.geometry,
id = em.id
};
ObsList.Add(fi);
}
//listEarthquakes.ItemsSource = ObsList;
Debug.WriteLine("EndxBind " + DateTime.Now);
}
else
{
//No Data
}
}
else
{
//Net Error
}
}
Note:
GetdEarthquakesGeoJsonAsync() returns all the data.
For example:
BeginRequest 8/17/2017 5:38:20 PM
EndRequest 8/17/2017 5:38:21 PM
BeginxBind 8/17/2017 5:38:21 PM
Count 1798
EndxBind 8/17/2017 5:38:21 PM
I use Debug.WriteLine to print the time, and found that the web request and response time is very short, and ObsList.Add(fi), also takes a few little time.
But my software is very very slow while scrolling down.
So how to improve it, thanks a lot.

Remove ScrollViewer over ListView. It disables ListView virtualization. ListView have it's own ScrollViewer.
Enable Virtualization to ListView
Read about virtualization here: https://learn.microsoft.com/en-us/windows/uwp/debug-test-perf/optimize-gridview-and-listview

Related

WPF Does not display vertical scrollbar

i am trying to create an application that will display user controls, based on information collected from DB. The problem is that if items total height exceeds mainwindow grid reserved for this display, i do not see a vertical scrollbar. From what i had found there might be an issue, that stackpanel/scrollviewer does not limit size of it's children. Im stuck on how to solve this, is there any way to stack items in limited spaces with scrollbar visible only when needed.
I want to avoid "hardcoding" the height of scrollviewer.
For now i'm stuck with below code:
XAML: (main window)
<Grid Name="selectedOptionGrid"
Grid.Column="1"
Grid.Row="1"
HorizontalAlignment="Left"
VerticalAlignment="Top">
<StackPanel Name="selectedOptionStack"/>
<!-- Dock selected windows based on option selected-->
</Grid>
(user control, additional window docked to mainwindow)
<UserControl x:Class="Power_Planner_1._0.Team_Planner.MyTasks.ucTaskWindow"
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:Power_Planner_1._0.Team_Planner.MyTasks"
mc:Ignorable="d">
<Grid Background="White"
VerticalAlignment="Stretch"
HorizontalAlignment="Stretch">
<Grid.RowDefinitions>
<RowDefinition Height="20"/>
<RowDefinition Height="5"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<StackPanel Grid.Row="0"
Orientation="Horizontal"
VerticalAlignment="Top"
Margin="0,5,0,0">
<TextBlock Margin="60,0,0,0" Width="160" FontWeight="Bold">Task Name</TextBlock>
<TextBlock Margin="10,0,0,0" Width="160" FontWeight="Bold">Team Name</TextBlock>
<TextBlock Margin="0,0,0,0" Width="55" FontWeight="Bold">Deadline</TextBlock>
<TextBlock Margin="20,0,0,0" Width="60" FontWeight="Bold">Start</TextBlock>
<TextBlock Margin="28,0,0,0" Width="60" FontWeight="Bold">End</TextBlock>
<TextBlock Margin="20,0,0,0" Width="60" FontWeight="Bold">Run Time</TextBlock>
</StackPanel>
<Separator Grid.Row="1"
VerticalAlignment="Top"/>
<Grid Name="taskListGrid"
Grid.Row="2"
Height="510"
Width="830">
<ScrollViewer VerticalScrollBarVisibility="Auto"
Width="{Binding ActualWidth,RelativeSource={RelativeSource
Mode=FindAncestor, AncestorType=Grid}}"
Height="{Binding ActualHeight,RelativeSource={RelativeSource
Mode=FindAncestor, AncestorType=Grid}}">
<StackPanel Orientation="Vertical"
x:Name="taskListStack">
<StackPanel.Resources>
<Style TargetType="UserControl">
<Setter Property="Margin" Value="0,5,0,0"/>
</Style>
</StackPanel.Resources>
</StackPanel>
</ScrollViewer>
</Grid>
</Grid>
</UserControl>
And finally an Items that are created:
<UserControl x:Class="Power_Planner_1._0.Team_Planner.MyTasks.ucTaskItem"
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:Power_Planner_1._0.Team_Planner.MyTasks"
xmlns:materialDesign="http://materialdesigninxaml.net/winfx/xaml/themes"
mc:Ignorable="d" d:DesignHeight="45">
<Border CornerRadius="12,12,12,12"
BorderThickness="1,1,1,1"
BorderBrush="LightGray"
Background="#FF456780"
Padding="0">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="50"/>
<ColumnDefinition Width="160"/>
<ColumnDefinition Width="160"/>
<ColumnDefinition Width="65"/>
<ColumnDefinition Width="90"/>
<ColumnDefinition Width="90"/>
<ColumnDefinition Width="65"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<!--Picture-->
<Border Grid.Column="0"
CornerRadius="25,25,25,25"
BorderThickness="1,1,1,1"
Width="30"
Height="30"
BorderBrush="LightGray"
Background="ForestGreen"
HorizontalAlignment="Left"
Margin="10,0,0,0">
</Border>
<!--Task Name-->
<TextBlock Grid.Column="1"
Margin="10,0,0,0"
FontSize="12"
Foreground="LightGray"
Text="{Binding taskName}"
Width="160"
VerticalAlignment="Center">
</TextBlock>
<!--Team Name-->
<TextBlock Grid.Column="2"
Margin="20,0,0,0"
FontSize="12"
Foreground="LightGray"
Text="{Binding teamName}"
Width="160"
VerticalAlignment="Center">
</TextBlock>
<!--Deadline-->
<TextBlock Grid.Column="3"
Margin="20,0,0,0"
FontSize="12"
Foreground="LightGray"
Text="{Binding deadline}"
Width="45"
VerticalAlignment="Center">
</TextBlock>
<!--Start-->
<Button Grid.Column="4"
Background="#FF456780"
BorderBrush="LightGray"
Height="25"
Margin="20,0,0,0"
Width="60">
<Button.Resources>
<Style TargetType="{x:Type Border}">
<Setter Property="CornerRadius" Value="10"/>
</Style>
</Button.Resources>
<TextBlock Foreground="LightGray">Start</TextBlock>
</Button>
<!--Stop-->
<Button Grid.Column="5"
Background="#FF456780"
BorderBrush="LightGray"
Height="25"
Margin="20,0,0,0"
Width="60">
<Button.Resources>
<Style TargetType="{x:Type Border}">
<Setter Property="CornerRadius" Value="10"/>
</Style>
</Button.Resources>
<TextBlock Foreground="LightGray">Stop</TextBlock>
</Button>
<!--Deadline-->
<TextBlock Grid.Column="6"
Margin="20,0,0,0"
FontSize="12"
Foreground="LightGray"
Text="{Binding runtime}"
Width="45"
VerticalAlignment="Center">
</TextBlock>
<!--Other Options-->
<materialDesign:PopupBox Grid.Column="7"
StaysOpen="False"
Foreground="White"
HorizontalAlignment="Right">
<StackPanel Width="150"
Background="White">
<Button Content="Edit"/>
<Button Content="View Details"/>
<Button Content="Comment"/>
</StackPanel>
</materialDesign:PopupBox>
</Grid>
</Border>
</UserControl>
Code to add items:
taskListStack.Children.Clear();
var task1 = new clsTaskItem("Test1", "blablabla", "12:40", "02:30");
taskListStack.Children.Add(new ucTaskItem(task1));
var task2 = new clsTaskItem("Test2", "blablabla", "13:45");
taskListStack.Children.Add(new ucTaskItem(task2));
var task3 = new clsTaskItem("Test3", "blablabla", "11:45");
taskListStack.Children.Add(new ucTaskItem(task3));
var task4 = new clsTaskItem("Test4", "blablabla", "14:45");
taskListStack.Children.Add(new ucTaskItem(task4));
var task5 = new clsTaskItem("Test5", "blablabla", "17:45");
taskListStack.Children.Add(new ucTaskItem(task5));
var task6 = new clsTaskItem("Test6", "blablabla", "18:45");
taskListStack.Children.Add(new ucTaskItem(task6));
var task7 = new clsTaskItem("Test7", "blablabla", "13:23");
taskListStack.Children.Add(new ucTaskItem(task7));
var task8 = new clsTaskItem("Test8", "blablabla", "12:54");
taskListStack.Children.Add(new ucTaskItem(task8));
var task9 = new clsTaskItem("Test9", "blablabla", "17:23");
taskListStack.Children.Add(new ucTaskItem(task9));
var task10 = new clsTaskItem("Test10", "blablabla", "17:10");
taskListStack.Children.Add(new ucTaskItem(task10));
taskListStack.Children.Add(new ucTaskItem(task1));
taskListStack.Children.Add(new ucTaskItem(task2));
taskListStack.Children.Add(new ucTaskItem(task3));
taskListStack.Children.Add(new ucTaskItem(task4));
taskListStack.Children.Add(new ucTaskItem(task5));
taskListStack.Children.Add(new ucTaskItem(task6));
taskListStack.Children.Add(new ucTaskItem(task7));
taskListStack.Children.Add(new ucTaskItem(task8));
taskListStack.Children.Add(new ucTaskItem(task9));
taskListStack.Children.Add(new ucTaskItem(task10));
And task item class ( to which items are binded via datacontext)
public class clsTaskItem
{
public clsTaskItem(string tsname, string tmname, string dline, string rtime = "00:00:00")
{
taskName = tsname;
teamName = tmname;
deadline = dline;
runtime = rtime;
}
public string taskName { get; private set; }
public string teamName { get; private set; }
public string deadline { get; private set; }
public string runtime { get; private set; }
}
As you can see i had tried to bind the scrollviewer height to grid i had created on top of it, thinking that if i set height to auto, it will get the height from the grid actual height. Well that didn't make much sense hence it was not working. I'm trying to find another solution for grouping the items, that way that i could expand easily main window, without coding each window to expand with this expansion so that items would both fill all available space and display scrollbar when needed.
Please help :)

Re-Sort a ListView in C# - UWP

I've created a XAML UWP Listview
<ListView x:Name="ThisList"
Grid.Row="3"
Grid.ColumnSpan="7"
Background="LightBlue"
IsItemClickEnabled="True"
BorderBrush="Black"
BorderThickness="2"
ItemClick="ThisList_ItemClick">
<ListView.ItemContainerStyle>
<Style TargetType="ListViewItem">
<Setter Property="HorizontalContentAlignment" Value="Stretch" />
</Style>
</ListView.ItemContainerStyle>
<ListView.ItemTemplate>
<DataTemplate>
<Grid BorderThickness="1" BorderBrush="Black">
<Grid.Resources>
<local:ColourConverter x:Key="CCX"/>
</Grid.Resources>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="50"/>
<ColumnDefinition Width="10*" MinWidth="500"/>
<ColumnDefinition Width="170"/>
<ColumnDefinition Width="100"/>
</Grid.ColumnDefinitions>
<Border Background="Aquamarine" Grid.Column="0">
<SymbolIcon Symbol="{Binding Icon}" HorizontalAlignment="Center" Margin="10"/>
</Border>
<Border Background="Yellow" Grid.Column="1">
<TextBlock Name="tbFileName" Text="{Binding FName}" VerticalAlignment="Center" Margin="5" />
</Border>
<Border Background="Cyan" Grid.Column="2">
<!--<TextBlock Text="{Binding FTime}" VerticalAlignment="Center" Margin="5" />-->
<TextBlock Text="{Binding FTime}"
Name="FileTime"
VerticalAlignment="Center"
HorizontalAlignment="Center"
Foreground="{Binding ElementName=FileTime,
Path=Text,
Mode=OneWay,
Converter={StaticResource CCX}}"/>
</Border>
<Border Background="Tomato" Grid.Column="3">
<TextBlock Text="{Binding FSize}" HorizontalAlignment="Right" Margin="10" />
</Border>
</Grid>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
The code behind is
var folderItem = new ObservableCollection<FolderInfo>();
foreach (StorageFolder folder in folderList)
{
BasicProperties pro = await folder.GetBasicPropertiesAsync();
folderItem.Add(new FolderInfo()
{
FName = folder.DisplayName,
FSize = "",
FTime = lastFileSave,
FIsFolder = true
});
}
foreach (StorageFile file in fileList)
{
BasicProperties pro = await file.GetBasicPropertiesAsync();
lastFileSave = file.DateCreated.ToString(Globals.TimeFormat);
folderItem.Add(new FolderInfo()
{
//FName = file.DisplayName,
FName = file.Name,
FSize = GetFileSize(pro.Size),
FTime = lastFileSave,
FIsFolder = false,
Icon="Document"
});
}
showLoadingBox(false);
FileInfo.Text += $"Last file saved : {lastFileSave}";
ThisList.ItemsSource = folderItem;
So my question is that I'd like to create a header row that I can click on the title and it re-sorts the ListView by that column, and if I click again it re-sorts descending.
What is the best way to achieve this?
Ok so there was no rush of answers so I have created a separate grid to make the header, and added a tapped event to requery the data source, but to do a query on it as it is assigned to the listview source as follows.
ThisList.ItemsSource = (from FolderInfo in folderItem
orderby FolderInfo.RealDateTime
select FolderInfo);
It's probably not the most efficient way of doing things, but currently the only way I can see of doing it without the ListView having some kind of sort method available.
Would appreciate any comments if there is a better way of doing it.

Click event on an item template

I have this wpf code for my listbox item:
<ListBox x:Name="icTodoList" ItemsSource="{Binding ListControleMachine}" Grid.Column="3">
<ListBox.ItemTemplate>
<DataTemplate>
<Border BorderBrush="{Binding borderColor}" BorderThickness="2" Margin="0,0,0,1">
<Grid Margin="1">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="30"/>
<ColumnDefinition Width="20"/>
<ColumnDefinition Width="100"/>
<ColumnDefinition Width="120"/>
<ColumnDefinition Width="130"/>
<ColumnDefinition Width="120"/>
<ColumnDefinition Width="120"/>
<ColumnDefinition Width="120"/>
<ColumnDefinition Width="120"/>
</Grid.ColumnDefinitions>
<CheckBox x:Name="check_action" Content="" HorizontalAlignment="Left" VerticalAlignment="Top" IsChecked="{Binding ActionCheked,Mode=TwoWay}"/>
<Ellipse x:Name="E_Ping" HorizontalAlignment="Left" Fill="{Binding PingDotColor}" Height="10" Width="10" Margin="2,4,0,0" VerticalAlignment="Top" RenderTransformOrigin="0.2,-1.182" Grid.Column="1"/>
<TextBlock Text="{Binding titlePing}" Grid.Column="2" MouseDown="TextBlock_MouseDown" Tag="{Binding ComputerName}"/>
<TextBlock Text="{Binding titlePing}" Grid.Column="2" MouseDown="TextBlock_MouseDown" Tag="{Binding ComputerName}"/>
<TextBlock Text="{Binding titleDcai}" Grid.Column="3" MouseDown="TextBlock_MouseDown" Tag="{Binding ComputerName}"/>
<TextBlock Text="{Binding titleAd}" Grid.Column="4" MouseDown="TextBlock_MouseDown" Tag="{Binding ComputerName}"/>
<TextBlock Text="{Binding FPACtitle}" Grid.Column="5" MouseDown="TextBlock_MouseDown" Tag="{Binding ComputerName}"/>
<TextBlock Text="{Binding titleMcAfee}" Grid.Column="6" MouseDown="TextBlock_MouseDown" Tag="{Binding ComputerName}"/>
<TextBlock Text="{Binding gkUser}" Grid.Column="7" MouseDown="TextBlock_MouseDown" Tag="{Binding ComputerName}"/>
<TextBlock Text="{Binding titleservicestat}" Grid.Column="8" MouseDown="TextBlock_MouseDown" Tag="{Binding ComputerName}"/>
</Grid>
</Border>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
As you can see I have a "TextBlock_MouseDown" on each textbox
Then the c# code.
private void TextBlock_MouseDown(object sender, MouseButtonEventArgs e)
{
TextBlock t = sender as TextBlock;
DetailedView.DataContext = ListControleMachine.Where(x => x.ComputerName == t.Tag.ToString());
DetailedView.Visibility = System.Windows.Visibility.Visible;
}
Ok, so it does what I need basically it pop a view with data rebinded to it.
but I'm pretty sure its not a clean way to do it.
first I don't wont event on each textblock but on the listboxitem it self (but I don't know how to pass computername argument this way).
second and may bee my only problem I think I don't have to search my collection and rebind my new view with this:
DetailedView.DataContext = ListControleMachine.Where(x => x.ComputerName == t.Tag.ToString());
for be clear how to click an item template and pop a view that will contain actual listbox item binded data?
try set DataContext via binding to SelectedItem of ListBox
<DetailedView DataContext="{Binding Path=SelectedItem, ElementName=icTodoList, Mode=OneWay}"/>
or equivalent code
var binding = new Binding
{
Path = new PropertyPath("SelectedItem"),
ElementName = "icTodoList",
Mode = BindingMode.OneWay
};
BindingOperations.SetBinding(DetailedView, Control.DataContextProperty, binding);
another approach
ListBox has SelectionChanged event
<ListBox Name="icTodoList"
SelectionChanged="IcTodoList_OnSelectionChanged">
</ListBox>
event handler
private void IcTodoList_OnSelectionChanged(object sender, SelectionChangedEventArgs e)
{
DetailedView.DataContext = icTodoList.SelectedItem;
DetailedView.Visibility = System.Windows.Visibility.Visible;
}
Tag values and TextBlock_MouseDown handler will be not necessary

Grouped Listview windows-phone

I'm trying to to show a grouped Listview based on this class
private class EInfo
{
public double JD { get; set; }
public string Date { get; set; }
public string Time { get; set; }
public string Details { get; set; }
public string MoreDetails { get; set; }
public string Icon { get; set; }
}
private List<EInfo> MEphemeries = new List<EInfo>();
This is how I grouped and ordered all the elements in every group:
IEnumerable<IGrouping<string, EInfo>> query = MEphemeries.GroupBy(pet => pet.Details);
foreach (var group in query)
{
Debug.WriteLine("Group {0}", group.Key);
group.OrderBy(a => a.JD);
foreach (var user in group)
{
Debug.WriteLine(" {0}", user.Date);
}
}
listviewME.ItemsSource = query;
And here goes the XAML:
<SemanticZoom Grid.Row="1" Background="Black" x:Name="semanticZoom" >
<SemanticZoom.ZoomedInView>
<ListView x:Name="listviewME" IncrementalLoadingThreshold="15">
<!--<ListView.SemanticZoomOwner>
<SemanticZoom/>
</ListView.SemanticZoomOwner>-->
<ListView.Header>
<!-- table header-->
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition x:Name="listviewMEHeader0" Width="140"/>
<ColumnDefinition x:Name="listviewMEHeader1" Width="60"/>
<ColumnDefinition x:Name="listviewMEHeader2" Width="*"/>
</Grid.ColumnDefinitions>
<Grid Grid.Column="0" Background="{StaticResource MediumGreyThemeColor}" Margin="0, 0.5, 0, 0.5">
</Grid>
<Grid Grid.Column="1" Background="{StaticResource MediumGreyThemeColor}" Margin="0, 0.5, 0, 0.5">
</Grid>
<Grid Grid.Column="2" Background="{StaticResource MediumGreyThemeColor}" Margin="0, 0.5, 0, 0.5">
</Grid>
</Grid>
</ListView.Header>
<ListView.ItemTemplate>
<DataTemplate>
<Grid Background="Black" Margin="0,0,0,0">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="140"/>
<ColumnDefinition Width="60"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Grid Grid.Column="0" Background="{StaticResource DarkGreyThemeColor}" Margin="0, 0, 0, 0.5">
<StackPanel>
<TextBlock Text="{Binding Date}" Margin="5" HorizontalAlignment="Center" VerticalAlignment="Center" Style="{StaticResource FlyoutPickerTitleTextBlockStyle}"/>
<TextBlock Text="{Binding Time}" Margin="5,0,5,5" HorizontalAlignment="Center" VerticalAlignment="Center" Style="{StaticResource BaseTextBlockStyle}" FontSize="14" Foreground="{StaticResource LightGreyThemeColor}"/>
</StackPanel>
</Grid>
<Grid Grid.Column="1" Background="{StaticResource DarkGreyThemeColor}" Margin="0, 0, 0, 0.5">
<!--<Rectangle Height="25" Width="25" Margin="0" Fill="{StaticResource MoonThemeColor}" RadiusX="12.5" RadiusY="12.5" />
<Rectangle Height="35" Width="35" Margin="0" Stroke="{Binding Color}" StrokeThickness="2" RadiusX="17.5" RadiusY="17.75" />-->
<Image Height="30" Width="30" Margin="0" Source="{Binding Icon}" Stretch="Uniform" />
</Grid>
<Grid Grid.Column="2" Background="{StaticResource DarkGreyThemeColor}" Margin="0, 0, 0, 0.5" Width="{Binding ActualWidth, ElementName=listviewMEHeader2}">
<StackPanel>
<TextBlock Text="{Binding Details}" Margin="5" HorizontalAlignment="Center" VerticalAlignment="Center" Style="{StaticResource FlyoutPickerTitleTextBlockStyle}" Foreground="{StaticResource VeryLightGreyThemeColor}"/>
<TextBlock Text="{Binding MoreDetails}" Margin="5,0,5,5" HorizontalAlignment="Center" VerticalAlignment="Center" Style="{StaticResource BaseTextBlockStyle}" FontSize="14" Foreground="{StaticResource LightGreyThemeColor}"/>
</StackPanel>
</Grid>
</Grid>
</DataTemplate>
</ListView.ItemTemplate>
<ListView.GroupStyle>
<GroupStyle HidesIfEmpty="True">
<GroupStyle.HeaderTemplate>
<DataTemplate>
<Border Grid.Column="0" Grid.ColumnSpan="3" MinWidth="400" BorderThickness="2" BorderBrush="Blue" Background="AliceBlue" Margin="0,10,5,0" CornerRadius="1">
<TextBlock Foreground="White" Text="{Binding Key}"
Margin="10,2,2,5" TextTrimming="WordEllipsis" TextWrapping="NoWrap"
FontWeight="SemiBold" FontSize="10" />
</Border>
</DataTemplate>
</GroupStyle.HeaderTemplate>
</GroupStyle>
</ListView.GroupStyle>
</ListView>
</SemanticZoom.ZoomedInView>
<SemanticZoom.ZoomedOutView>
<ListView Margin="5" ItemsSource="{Binding query}" Background="White">
<ListView.ItemTemplate>
<DataTemplate>
<Grid Height="99" Margin="16">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Border Background="{StaticResource MediumDarkGreyThemeColor}" Width="200" Height="111">
<Grid>
<TextBlock Text="{Binding Group.Key}" Style="{ThemeResource SubheaderTextBlockStyle}" />
</Grid>
</Border>
</Grid>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</SemanticZoom.ZoomedOutView>
</SemanticZoom>
The question is that all the info is grouped Ok, every group with its key, its list of elements correctly ordered by date, but the listview doesn't shows any info. It only some empty blocks (the number of block is the same to the number of groups).
What is the problem? How I can fix this?
This is what I get:
This is what I want to achieve:
Thank you in advance!
Some stuff I see that might fix your problems:
1) Change your private class EInfo to public
2) Your first ListView does not have ItemsSource set while your second LiewView has it set to ItemsSource="{Binding query}"
3) You can group your ListView and GridView nicely by using a CollectionViewSource see here : CollectionViewSource example
4) Or you can do it manually by Grouping it into an AlphaKeyGroup, I have a working example here : AlphaKeyGroup
Last idea, is to check the output of your GroupBy code vs the CollectionViewSource and AlphaKeyGroup in the debugger to see if they match up.

how to get listboxitem's value on listbox hold event?

xmal code:
<ListBox x:Name="listbox2" Margin="0,0" SelectionChanged="listbox2_SelectionChanged" Hold="listbox2_Hold" >
<ListBox.ItemContainerStyle >
<Style TargetType="ListBoxItem">
<Setter Property="HorizontalContentAlignment" Value="Stretch"></Setter>
</Style>
</ListBox.ItemContainerStyle>
<ListBox.ItemTemplate>
<DataTemplate>
<Border BorderThickness="0,0,0,1" BorderBrush="Gray">
<Grid Width="auto" HorizontalAlignment="Stretch" >
<Grid.RowDefinitions>
<RowDefinition Height="*"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="150"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<TextBlock VerticalAlignment="Center" FontSize="40" Grid.Column="1" Grid.Row="0" Foreground="White" Text="{Binding NAME}"></TextBlock>
<TextBlock VerticalAlignment="Center" FontSize="25" Grid.Column="1" Grid.Row="1" Foreground="Blue" Text="{Binding PHONE}"></TextBlock>
<Image Name="c1" HorizontalAlignment="Left" VerticalAlignment="Top" Width="100" Height="100" Stretch="Fill" Margin="0" Source="{Binding IMGS}" Grid.RowSpan="2" Grid.Column="0" />
</Grid>
</Border>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
class list which is bind to list box is
List < contactsclass > contacts = new List < contactsclass >();
PHONE and NAME are getter setter of the contactclass's variables
how can i get this variable's value on hold event of listbox .. i am trying following code
private void listbox2_Hold(object sender, System.Windows.Input.GestureEventArgs e)
{
//contextmenucontact = (contactsclass)(sender as ListBox).DataContext;
contextmenucontact = (contactsclass)listbox2.SelectedItem;
MessageBox.Show(contextmenucontact.name);
}
if is just the selected item is just use the ToString Function, see this:
if (listBox1.SelectedItem != null)
{
string itemText = listBox1.SelectedItem.ToString();
contextmenucontact = new contactsclass();
contextmenucontact.name = itemText;
MessageBox.Show(contextmenucontact.name);
}

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