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How to get the destination ListView item on drop?

In UWP C#, I have one ListView in upper row & another in lower row. When I drag a listitem from upper ListView & drop it on lower ListView, I am getting the source. But, I am unable to get the destination. ie) the listview item/(Folder object in my case) where I dropped.
<ListView Name="ListviewCars"
CanDragItems="True" DragItemsStarting="ListviewCars_DragItemsStarting"
SelectionMode="Single" IsItemClickEnabled="True"
DataContext="Cars" ItemsSource="{Binding CarsCollection}">
<ListView.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel Background="Transparent" Height="80" Orientation="Horizontal"
HorizontalAlignment="Stretch" VerticalAlignment="Stretch" />
</ItemsPanelTemplate>
</ListView.ItemsPanel>
<ListView.ItemTemplate >
<DataTemplate>
<Grid Name="GrdCars" >
<Grid Height="80" Width="90" Padding="5">
<Grid.Background>
<ImageBrush Stretch="Uniform" ImageSource="Assets/car.png"/>
</Grid.Background>
<TextBlock Text="{Binding Name}" FontWeight="Bold" TextWrapping="Wrap" TextAlignment="Center"
HorizontalAlignment="Center" VerticalAlignment="Center" />
</Grid>
</Grid>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
<ListView Name="GrdViewImg" ScrollViewer.VerticalScrollBarVisibility="Disabled"
AllowDrop="True" DragOver="Image_DragOver"
Drop="Image_OnDrop"
DataContext="Folders" ItemsSource="{Binding FolderCollection}">
<ListView.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel Background="Transparent" Height="80" Orientation="Horizontal" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" />
</ItemsPanelTemplate>
</ListView.ItemsPanel>
<ListView.ItemTemplate >
<DataTemplate>
<Grid Name="GrdForFolderMenu" RightTapped="GrdForFolderMenu_RightTapped">
<Grid Height="80" Width="90" Padding="5">
<Grid.Background>
<ImageBrush Stretch="UniformToFill" ImageSource="Assets/Folderimage.png"/>
</Grid.Background>
<TextBlock Text="{Binding Name}" FontWeight="Bold" TextWrapping="Wrap" TextAlignment="Center" HorizontalAlignment="Center" VerticalAlignment="Center" />
</Grid>
</Grid>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>

I have found a simple solution myself. I get the source from DragItemsStarting event of the SoureListView. and target item (as mentioned by ashchuk) from a Grid placed inside Datatemplate of Target ListView. as shown below. Everything works fine now!
(Cars is my Source custom list item. Folders is my Target custom list item)
private void SoureListView_DragItemsStarting(object sender, DragItemsStartingEventArgs e)
{
Cars x = e.Items[0] as Cars;
string DraggedSourceCar = x.Name;
e.Data.Properties.Add("myArgs", DraggedSourceCar);
}
private void GridInsideDatatemplateOfTargetListview_Drop(object sender, DragEventArgs e)
{
var x = sender as Grid;
var y = x.DataContext as Folders;
string toMoveFolderName = y.Name;
string DraggedSourceCar = e.DataView.Properties["myArgs"].ToString();
Debug.WriteLine(DraggedSourceCar + Environment.NewLine + toMoveFolderName );
}
private void TargetListview_DragOver(object sender, DragEventArgs e)
{
e.AcceptedOperation = DataPackageOperation.Copy;
}

You have to find out by yourself = DragEventArgs.GetPosition() in the destination drop, then the underlying item with smoe helper functions
public static object GetObjectAtPoint<ItemContainer>(this ItemsControl control, Point p)
where ItemContainer : DependencyObject
{
// ItemContainer - can be ListViewItem, or TreeViewItem and so on(depends on control)
ItemContainer obj = GetContainerAtPoint<ItemContainer>(control, p);
if (obj == null)
return null;
return control.ItemContainerGenerator.ItemFromContainer(obj);
}
public static ItemContainer GetContainerAtPoint<ItemContainer>(this ItemsControl control, Point p)
where ItemContainer : DependencyObject
{
HitTestResult result = VisualTreeHelper.HitTest(control, p);
if (result != null)
{
DependencyObject obj = result.VisualHit;
while (VisualTreeHelper.GetParent(obj) != null && !(obj is ItemContainer))
{
obj = VisualTreeHelper.GetParent(obj);
}
// Will return null if not found
return obj as ItemContainer;
}
else return null;
}

Did you checked this sample?
After some research I found what DragEventArgs contains an OriginalSource property with Name matches the name of target list when Drop event invoked.
I'm not checked it with folders and subfolders, but maybe OriginalSource will contain folder where item dropped.
<TextBlock Grid.Row="1" Margin="8,4"
VerticalAlignment="Bottom"
Text="All Items"/>
<ListView x:Name="SourceListView"
Grid.Row="2" Margin="8,4"
SelectionMode="Extended"
CanDragItems="True"
DragItemsStarting="SourceListView_DragItemsStarting"/>
<TextBlock Grid.Row="1" Grid.Column="1" Margin="8,4"
VerticalAlignment="Bottom"
Text="Selection"/>
<ListView x:Name="TargetListView"
Grid.Row="2" Grid.Column="1" Margin="8,4"
AllowDrop="True" CanReorderItems="True" CanDragItems="True"
DragOver="TargetListView_DragOver"
Drop="TargetListView_Drop"
DragItemsStarting="TargetListView_DragItemsStarting"
DragItemsCompleted="TargetListView_DragItemsCompleted"/>
And here is printscreen with fired breakpoint:
EDIT:
To get an item inside of TargetList you can do a trick.
I think you use DataTemplate to display custom list items ("folders"). You can see a sample below. As you see I add Grid_DragOver trigger.
<Page.Resources>
<DataTemplate x:Key="ListViewDataTemplate">
<Grid Margin="20,5" DragOver="Grid_DragOver"
BorderBrush="White" BorderThickness="5" AllowDrop="True">
<TextBlock Margin="10" LineHeight="40" FontSize="32" FontWeight="Bold"/>
</Grid>
</DataTemplate>
</Page.Resources>
This way Grid_DragOver will be invoked when mouse pointer enter inside the Grid in DataTemplate.
And if you use binding List<YourFolderClass> as data source, you'll get folder in DataContext. For example I used this:
var SampleData = new ObservableCollection<string>
{
"My Research Paper",
"Electricity Bill",
"My To-do list",
"TV sales receipt",
"Water Bill",
"Grocery List",
"Superbowl schedule",
"World Cup E-ticket"
};
You can see all code in gist.

MVVM access Richtextbox flowdocument from VM

I am trying to make a RichTextBox with a FlowDocument that I can insert text at the caret position. I can add text to the end of the document. I think I am missing something in my setup to that allows my VM to access the Flowocument or I am setting it up wrong. If I create a FlowDocument in my VM and try to set my RichTextBox to it I get an error that my MyEditor (RichTextBox) does not exist. I can add text to the RichTextBox using what I call the AddItemBtn from a ListBox so at least that much works.
My question is "How should I set my RichTextBox/FlowDocument up?
XAML code
<Window x:Class="Scripter.Views.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:Scripter.ViewModels"
xmlns:wpftoolkit="clr-namespace:Xceed.Wpf.Toolkit;assembly=Xceed.Wpf.Toolkit"
Title="MainWindow" Height="350" Width="725">
<Grid HorizontalAlignment="Stretch">
<Grid HorizontalAlignment="Stretch" Height="72" Margin="10,14,0,0" VerticalAlignment="Top" Width="auto">
<WrapPanel HorizontalAlignment="Left" Height="50" Margin="10,0,0,0" VerticalAlignment="Top">
</WrapPanel>
<Button x:Name="OpenFilesBtn" Content="Open" HorizontalAlignment="Left" Margin="15,10,0,0" VerticalAlignment="Top" Width="75" Command="{Binding OpenFileBtn}"/>
<Button x:Name="SavefilesBtn" Content="Save" HorizontalAlignment="Left" Margin="104,10,0,0" VerticalAlignment="Top" Width="75" Command="{Binding SaveFileBtn}"/>
<TextBlock x:Name="OpenFile" Text="{Binding OpenFile,Mode=OneWay, UpdateSourceTrigger=PropertyChanged}" HorizontalAlignment="Left" Margin="15,37,0,0" VerticalAlignment="Top" Width="353"/>
<ComboBox x:Name="TipsBtn" SelectedIndex="0" ItemsSource="{Binding Path=Tabs, UpdateSourceTrigger=PropertyChanged}" SelectedItem="{Binding Path=SelectedOption}" HorizontalAlignment="Left" Margin="538,10,0,0" VerticalAlignment="Top" Width="120"/>
<Button x:Name="AddItemBtn" Content="Add Item" HorizontalAlignment="Left" Margin="417,10,0,0" VerticalAlignment="Top" Width="100" Command="{Binding AddItemBtn}" CommandParameter="{Binding ElementName=AddItemList,Path=SelectedItem}"/>
</Grid>
<Grid Margin="10,100,10,0">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="2*"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<RichTextBox Grid.Column="0" x:Name="MyEditor" SelectionChanged="MyEditor_SelectionChanged" ScrollViewer.VerticalScrollBarVisibility="Auto" Margin="0" Height="Auto" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Width="Auto" IsDocumentEnabled="True" AcceptsTab="True" AcceptsReturn="True" >
<RichTextBox.Resources>
<Style TargetType="{x:Type Paragraph}">
<Setter Property="Margin" Value="0" ></Setter>
<Setter Property="FontSize" Value="15"></Setter>
</Style>
</RichTextBox.Resources>
<FlowDocument >
<Paragraph >
<Run Text="{Binding TestText}" ></Run>
</Paragraph>
</FlowDocument>
</RichTextBox>
<ListBox x:Name="AddItemList" Grid.Column="1" Width="Auto" Height="Auto" ItemsSource="{Binding Path=OptionsToChoose}" SelectedItem="ItemSelected">
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock x:Name="TextSelected" Text="{Binding Description}" />
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
</Grid>
VM code that has the issue
public ScripterViewModel()
{
ScripterModel scripterModel = new ScripterModel();
ObservableCollection<string> tabsChoice = new ObservableCollection<string>();
tabsChoice.Add("Tabs");
tabsChoice.Add("Buttons");
Tabs = tabsChoice;
this.OpenFileBtn = new DelegateCommand(chooseFile, canChooseFile).ObservesProperty(() => OpenFile);
this.SaveFileBtn = new DelegateCommand(saveFile, canSaveFile).ObservesProperty(() => SaveFile);
this.AddItemBtn = new DelegateCommand<Tabbed>(addItem);
FlowDocument flowDoc = new FlowDocument();
Paragraph p = new Paragraph(new Run("new paragraph"));
flowDoc.Blocks.Add(new Paragraph(new Run("Paragraph 1")));
flowDoc.Blocks.Add(p);
//MyEditor = flowDoc;
}
public void MyEditor_SelectionChanged(object sender, RoutedEventArgs e)
{
// TextRange tempRange = new TextRange(MyEditor.Document.ContentStart, MyEditor.Selection.Start);
MessageBox.Show("Selection Changed");
}
private string _testText;
public string TestText
{
get
{
return _testText;
}
set
{
string _temp;
_temp = _testText + value;
SetProperty(ref _testText, value);
}
}

Hey I am new to WPF and MVVM but I'll give my best to help you. So don't blame me if I'm wrong.
1. Set Window.DataContext
First of all you have to tell your View where it can get the data from.
This can be done by adding this code to your View.xaml:
<Window.DataContext>
<local:MainViewModel/>
</Window.DataContext>
But make sure your namespace variable (here "local") points to your ViewModels.
xmlns:local="clr-namespace:Client.ViewModel"
This for ex. points to my ViewModel folder.
2. Define a OnPropertyChanged method
Your View won't know if you have modified a variable. So you need a method to notify your View about the changes.
First of all implement the interface INotifyPropertyChanged to your ViewModel.
public class MainViewModel : ViewModelBase, INotifyPropertyChanged
Now add this code:
public event PropertyChangedEventHandler PropertyChanged;
public void OnPropertyChanged([CallerMemberName]string propertyName = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
3. Use OnPropertyChanged
So now you have a method to tell your View that a variable has changed but how do you use it?
To explain this to you I'll use your FlowDocument flowDoc.
So let's begin by defining your FlowDocument setting up :
private FlowDocument _flowDoc;
Now lets write a getter & setter for flowDoc:
public FlowDocument FlowDoc
{
get
{
return _flowDoc;
}
set
{
_flowDoc = value;
}
}
Now it's time to use our OnPropertyChanged method which we created in 2.
In the setter section you want to add the following Code:
OnPropertyChanged("variable");
Your result should now look like this:
public FlowDocument FlowDoc
{
get
{
return _flowDoc;
}
set
{
_flowDoc = value;
OnPropertyChanged("FlowDoc");
}
}
Important: remember to apply this to all your variables!
4. Use MVVM pattern right
In MVVM you have a Model a View and a ViewModel.
The Model is for your data so if possible don't store data in your ViewModel instead use a data class for ex.
You may have a look at this and/or this.
As I said in the beginning I'm new to all of this but i hope it helps
you. Feel free to ask.

Combo box add item from template

Im trying to add items to the combo box from the code behind to the item template but im getting null. This is what I have so far:
XAML:
<ListBox x:Name="lsbCiertoYFalsoInsideTemplate" Margin="40,0,0,0" ItemTemplate="{StaticResource CiertoYFalsoExcerciseDataTemplate}"/>
App.xaml:
<DataTemplate x:Key="CiertoYFalsoExcerciseDataTemplate">
<Grid>
<StackPanel x:Name="stckCiertoYFalsoInsideTemplate" Margin="0" Orientation="Vertical" Width="1100">
<StackPanel x:Name="stckPreguntasCiertoYFalso" Orientation="Horizontal">
<Grid Height="50" Width="65" DataContext="{Binding CustomValueList}" VerticalAlignment="Top">
<ComboBox x:Name="cbExercises" Style="{StaticResource SA_ComboBoxStyle}" ItemsSource="{Binding CustomOption}" BorderBrush="#CC8C8C8C" VerticalAlignment="Top">
</ComboBox>
</Grid>
<TextBlock HorizontalAlignment="Center" Margin="5,3,0,0" TextWrapping="Wrap" Text="{Binding QuestionNumber}" VerticalAlignment="Top" FontWeight="Bold" Foreground="Black" Width="26" FontFamily="{Binding FontFamily, Source={StaticResource TextBlockStyleManager}}" FontSize="{Binding FontSize, Source={StaticResource TextBlockStyleManager}}"/>
<TextBlock TextWrapping="Wrap" Text="{Binding Question}" Foreground="Black" VerticalAlignment="Top" FontSize="{Binding FontSize, Source={StaticResource TextBlockStyleManager}}" Margin="10,3,0,0" Width="968" FontFamily="{Binding FontFamily, Source={StaticResource TextBlockStyleManager}}"/>
</StackPanel>
</StackPanel>
</Grid>
</DataTemplate>
The error im getting is object out of range.
Code:
private void ComboBoxExercises()
{
ComboBox comboBox = new ComboBox();
ComboboxItem item = new ComboboxItem();
item.Text = "A";
comboBox = (ComboBox)lsbCiertoYFalsoInsideTemplate.FindName("cbExercises");
comboBox.SelectedIndex = 0;
comboBox.Items.Add(item);
}
public class ComboboxItem
{
public string Text { get; set; }
public override string ToString()
{
return Text;
}
}

There's a disconnect in what you're trying to do here. You've specified an ItemTemplate - which defines how each item in the list will look.
But then you're trying to get one single ComboBox back out via the FindName function. Which leads me to believe that you're really intending to set the Template, not the ItemTemplate.
That said, I think the error you're getting is because you're setting the SelectedIndex to 0 when the ComboBox has no items in it. You're telling it to select the first one, but there's nothing to select. You should add the item first, then select it.

List picker not showing items.

I have a list picker when clicking on the control to select another item it seems to look like it is going to work but is all white I can sometimes get it to select another item but cant see what is selected until you are off of it. This is how I have it set up. When I set it to full mode the name space is the only thing that shows not the actual name of the item. All I am trying to do is upon loading the view I need to load the listPicker with values.
<phone:PhoneApplicationPage.Resources>
<DataTemplate x:Name="PickerItemTemplate" >
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding TankTypeName}" Style="{StaticResource PhoneTextNormalStyle}"/>
</StackPanel>
</DataTemplate>
<DataTemplate x:Name="PickerFullModeItemTemplate">
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding TankTypeName}" Style="{StaticResource PhoneTextNormalStyle}" FontFamily="{StaticResource PhoneFontFamilyLight}"/>
</StackPanel>
</DataTemplate>
</phone:PhoneApplicationPage.Resources>
<!--ContentPanel - place additional content here-->
<Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
<TextBox Height="72" HorizontalAlignment="Left" Margin="0,50,0,0" Name="TextBoxProjectName" Text="" VerticalAlignment="Top" Width="456" />
<TextBlock Height="30" HorizontalAlignment="Left" Margin="12,28,0,0" Name="TextBlockProjectName" Text="Tank Name:" VerticalAlignment="Top" />
<toolkit:ListPicker Header="Tank Type:" ItemsSource="{Binding TankTypes}"
ItemTemplate="{StaticResource PickerItemTemplate}"
FullModeItemTemplate="{Binding PickerFullModeItemTemplate}"
SelectedItems="{Binding SelectedTankTypes,Mode=TwoWay}"
Height="100" HorizontalAlignment="Left"
Margin="6,144,0,0" Name="ListPickerTankType"
VerticalAlignment="Top" Width="444" >
</toolkit:ListPicker>
</Grid>
View Model
private List<TankType> _tankType;
private ObservableCollection<Object> _selectedTankType= new ObservableCollection<object>();
/// <summary>
/// Collection of Tank Type objects.
/// </summary>
public List<TankType> TankTypes
{
get
{
return _tankType;
}
set
{
if (value != _tankType)
{
_tankType = value;
NotifyPropertyChanged("TankType");
}
}
}
public ObservableCollection<object> SelectedTankTypes
{
get
{
return _selectedTankType;
}
set
{
if (_selectedTankType == value)
{
return;
}
_selectedTankType = value;
NotifyPropertyChanged("SelectedTankTypes");
}
}
This is a edit page so in the constructor of the view.
public TaskDetail()
{
InitializeComponent();
var tankTypeViewModel = new ViewModels.TankVewModel();
tankTypeViewModel.GetTankTypes();
ListPickerTankType.DataContext = tankTypeViewModel;
}
Revised OK I removed the height on the listpicker and now can see it made it bigger so the three items are there. I just cant seem to change the font color to black so I can see it when you click on the listpicker.

Figured it out. I needed to remove the height and set the foreground color to black.

WPF Bool DataTrigger - Change Font Colour

I want to change the font colour of a number of items on a WPF page based on the theme selected by the user. (there is a light theme, and a dark theme)
I'm using a datatemplate to customise the content of a listbox, when the theme is Dark, I want to change all the textblock font colours to White.
My the class behind the page I'm setting 'DarkTheme' to true.
I've successfully set triggers below, however I can't figure out how to do this from a value set on the pages class.
So, how can I style the font colour of the textblocks to white if DarkTheme = true?
Code:
public partial class Media : UserControl
{
public bool DarkTheme { get; set; }
readonly DatabaseAsset _dbAssets = new DatabaseAsset();
public Media()
{
InitializeComponent();
RefreshMediaList();
DarkTheme = Global.Configuration.IsDarkModeAppliedAsTheme();
}
}
XAML:
<UserControl.Resources>
<db:MediaAsset x:Key="MediaAsset"/>
<DataTemplate x:Key="MediaAssetItemTemplate">
<ListBoxItem Height="70" Name="ListBoxItem">
<DockPanel Margin="0,0,0,0" Height="65">
<DockPanel DockPanel.Dock="Left" Name="VideoImage2" Height="65" Width="102">
<Button Name="ListBoxItemSelect" Click="ButtonBase_OnClick" Tag="{Binding Path=Id}">
<Path Name="test" Width="38" Height="30.0833" Canvas.Left="19" Canvas.Top="22.1667" Stretch="Fill" Fill="#FF000000" Data="F1 M 19,34.8333L 22.1667,34.8333L 22.1667,42.75L 19,42.75L 19,34.8333 Z M 22.9583,34.0417L 49.4791,34.0417L 49.4791,38L 50.6667,38L 57,31.6667L 57,52.25L 50.6667,45.9167L 49.4791,45.9167L 49.4791,52.25L 22.9583,52.25L 22.9583,34.0417 Z M 29.2917,22.1667C 32.3522,22.1667 34.8333,24.6478 34.8333,27.7083C 34.8333,30.7689 32.3522,33.25 29.2917,33.25C 26.2311,33.25 23.75,30.7689 23.75,27.7083C 23.75,24.6478 26.2311,22.1667 29.2917,22.1667 Z M 41.9583,22.1667C 45.0189,22.1667 47.5,24.6478 47.5,27.7083C 47.5,30.7689 45.0189,33.25 41.9583,33.25C 38.8977,33.25 36.4167,30.7689 36.4167,27.7083C 36.4167,24.6478 38.8977,22.1667 41.9583,22.1667 Z "/>
</Button>
</DockPanel>
<DockPanel Dock="Left" Name="VideoData2" HorizontalAlignment="Stretch" Height="65">
<TextBlock DockPanel.Dock="Top" Text="{Binding Path=Title}" FontWeight="Bold" FontSize="18"></TextBlock>
<TextBlock DockPanel.Dock="Top" TextTrimming="CharacterEllipsis" Text="{Binding Path=Description}" TextWrapping="NoWrap" FontSize="13" Margin="0,0,0,0"/>
<StackPanel DockPanel.Dock="Top" Orientation="Horizontal">
<TextBlock Text="{Binding Path=VideoCatNane}" FontSize="12" FontStyle="Italic"/>
<Border Width="50"></Border>
<TextBlock Text="{Binding Path=MediaState}" FontSize="12"/>
</StackPanel>
</DockPanel>
</DockPanel>
</ListBoxItem>
</DataTemplate>
</UserControl.Resources>

That's not the right way to do theming in WPF.
But if you want a quick solution, Move the InitializeComponent() statement to the bottom of your constructor:
public Media()
{
RefreshMediaList();
DarkTheme = Global.Configuration.IsDarkModeAppliedAsTheme();
InitializeComponent(); // <-- Here
}