Develop Reference

TextBlock does not update after assigning the value

I am making a datagrid inside a window, where two columns are DockPanels with a TextBlock and a Button. When a user selects a file/folder, the TextBlock receives the value and displays it. However, it does not reflect it right away in my case. When I double click on the TextBlock, it suddenly shows. What am I missing here?
XAML
<DataGrid Name="copierDataGrid" Margin="30,50,30,100"
ItemsSource="{Binding SelectedAsm}" SelectedItem="{Binding Selected}" AutoGenerateColumns="False" CanUserResizeColumns="False" >
<DataGrid.Columns>
<DataGridTextColumn Header="Prefix" Width="70" Binding="{Binding prefCol, TargetNullValue=''}"/>
<DataGridTemplateColumn Width="235" CanUserResize="False" Header="Select File">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<DockPanel DockPanel.Dock="Top">
<TextBlock Name="fileLocColtxtBox" Width="185" Margin="0,0,0,0" TextWrapping="Wrap" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Text="{Binding fileLocCol, TargetNullValue=''}"/>
<Button x:Name="brwsFileBtn" Content="..." Width="30" Margin="0,0,0,0" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Click="brwsFileBtn_Click"/>
</DockPanel>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
<DataGridTextColumn Header="Suffix" Width="70" Binding="{Binding suffCol, TargetNullValue=''}"/>
<DataGridTemplateColumn Header="Target location" Width="*" CanUserResize="False" >
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<DockPanel DockPanel.Dock="Top">
<TextBlock Name="destLocColtxtBox" Width="180" Margin="0,0,0,0" TextWrapping="Wrap" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Text="{Binding destLocCol, TargetNullValue=''}"/>
<Button x:Name="brwsFileBtn" Content="Browse" Width="50" Margin="0,0,0,0" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Click="brwsFolderBtn_Click"/>
</DockPanel>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
</DataGrid.Columns>
</DataGrid>
XAML.CS
public itemAsm Selected { get; set; }
public ObservableCollection<itemAsm> SelectedAsm { get; set; }
public unitCopierFrm()
{
InitializeComponent();
SelectedAsm = new ObservableCollection<itemAsm>();
DataContext= this;}
public class itemAsm
{
public string prefCol { get; set; }
public string fileLocCol { get; set; }
public string suffCol { get; set; }
public string destLocCol { get; set; }
}
}private void brwsFolderBtn_Click(object sender, RoutedEventArgs e)
{
if (Selected !=null)
{
System.Windows.Forms.FolderBrowserDialog dlgFolderBrowser = new System.Windows.Forms.FolderBrowserDialog();
dlgFolderBrowser.Description = "Select the destination folder";
dlgFolderBrowser.RootFolder = System.Environment.SpecialFolder.MyComputer;
dlgFolderBrowser.ShowDialog();
string dirPath = dlgFolderBrowser.SelectedPath;
//if (dlgFolderBrowser.ShowDialog == Windows)
if (dirPath != null)
{
Selected.destLocCol = dirPath;
}
}
}

itemAsm should implement INotifyPropertyChanged and raise the PropertyChanged event to notify the view whenever the data-bound property has been set to a new value:
public class itemAsm : INotifyPropertyChanged
{
private string _prefCol;
public string prefCol
{
get { return _prefCol; }
set { _prefCol = value; NotifyPropertyChanged(); }
}
private string _fileLocCol;
public string fileLocCol
{
get { return _fileLocCol; }
set { _fileLocCol = value; NotifyPropertyChanged(); }
}
private string _suffCol;
public string suffCol
{
get { return _suffCol; }
set { _suffCol = value; NotifyPropertyChanged(); }
}
private string _destLocCol;
public string destLocCol
{
get { return _destLocCol; }
set { _destLocCol = value; NotifyPropertyChanged(); }
}
public event PropertyChangedEventHandler PropertyChanged;
private void NotifyPropertyChanged([CallerMemberName] String propertyName = "")
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
You may also want to consider renaming the properties according to the C# naming conventions.

C# UWP: Access a textblock and status of check box inside a listview

Hi I have my list view as follows:
![][1]
<RelativePanel >
<ListView x:Name="StudentListView"
IsItemClickEnabled="True"
Width="1000"
ItemClick="Student_ItemClick" >
<ListView.ItemTemplate>
<DataTemplate x:Name="ABC">
<StackPanel
x:Name="ListItemPanel"
Orientation="Horizontal"
MaxWidth="500">
<TextBlock x:Name ="uName" Text="{Binding Username}"
Margin="20,0,20,8"
FontSize="24"
FontStyle="Italic"
FontWeight="SemiBold"
Foreground="DarkBlue"
/>
<CheckBox Name="AttendCheckBox"
HorizontalAlignment="Left"
Checked="AttendCheckBox_Checked"
IsChecked="False"></CheckBox>
</StackPanel>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
<TextBlock Name="queryName" FontSize="20"></TextBlock>
<Button Name="finishBtn" Content="Finish" RelativePanel.Below="StudentListView" ></Button>
</RelativePanel>
I am trying to access each data item and check if checkbox is checked or not when user clicks on finish button that is on same page as listview. And I am having tough time trying to figure it out. Any hint on it would be great. Thank you

I checked your code. You did not need to use Checked event of CheckBox. Instead, you could declare a bool type property in your custom class and bind IsChecked to it and set Mode=TwoWay, then, once your checkbox's IsChecked value is changed, the source also will be updated. After that, you could filter the source to get the 'IsChecked=True' items.
According to your code snippet, I made a code sample for you reference:
<RelativePanel>
<ListView x:Name="StudentListView"
IsItemClickEnabled="True"
Width="1000" Height="500">
<ListView.ItemTemplate>
<DataTemplate x:Name="ABC">
<StackPanel
x:Name="ListItemPanel"
Orientation="Horizontal"
MaxWidth="500">
<TextBlock x:Name ="uName" Text="{Binding Username}"
Margin="20,0,20,8"
FontSize="24"
FontStyle="Italic"
FontWeight="SemiBold"
Foreground="DarkBlue"/>
<CheckBox Name="AttendCheckBox" HorizontalAlignment="Left" IsChecked="{Binding IsSelected,Mode=TwoWay}"></CheckBox>
</StackPanel>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
<TextBlock Name="queryName" FontSize="20"></TextBlock>
<Button Name="finishBtn" Content="Finish" RelativePanel.Below="StudentListView" Click="{x:Bind finishBtn_Click}"></Button>
</RelativePanel>
public sealed partial class MainPage : Page
{
public ObservableCollection<Test> tests { get; set; }
public MainPage()
{
this.InitializeComponent();
tests = new ObservableCollection<Test>();
for (int i=0;i<100;i++)
{
tests.Add(new Test() {Username="name "+i });
}
StudentListView.ItemsSource = tests;
}
private void finishBtn_Click(object sender, RoutedEventArgs e)
{
var selectedStudents = tests.Where(x => x.IsSelected == true).ToList();
}
}
public class Test : INotifyPropertyChanged
{
private string _Username;
public string Username
{
get { return _Username; }
set
{
if (_Username != value)
{
_Username = value;
RaisePropertyChanged("Username");
}
}
}
private bool _IsSelected;
public bool IsSelected
{
get { return _IsSelected; }
set
{
if (_IsSelected != value)
{
_IsSelected = value;
RaisePropertyChanged("IsSelected");
}
}
}
public event PropertyChangedEventHandler PropertyChanged;
private void RaisePropertyChanged(string PropertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this,new PropertyChangedEventArgs(PropertyName));
}
}
}

Selection & identification of child node in TreeView

I have created a treeview in my xaml.
<TreeView Name="exportTreeView" ItemsSource="{Binding}" Width="350" >
<TreeView.Resources>
<DataTemplate x:Key="layersTemplate">
<StackPanel Orientation="Horizontal" Margin="10,0,0,0">
<CheckBox Foreground="White" IsChecked="{Binding IsToBeExported}" VerticalAlignment="Center" />
<Label Style="{StaticResource baseStyle}" Content="{Binding Path=Name}" VerticalAlignment="Center" />
</StackPanel>
</DataTemplate>
<HierarchicalDataTemplate x:Key="objectTemplate" ItemsSource="{Binding Path=LayersList}" ItemTemplate="{StaticResource ResourceKey=layersTemplate}">
<StackPanel Orientation="Horizontal" Height="15" Margin="10,0,0,0">
<CheckBox Foreground="White" IsChecked="{Binding IsToBeExported}" VerticalAlignment="Center" />
<Label Style="{StaticResource baseStyle}" Content="{Binding Path=Name}" VerticalAlignment="Center" />
</StackPanel>
</HierarchicalDataTemplate>
</TreeView.Resources>
<TreeView.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Path=ObjectList}" ItemTemplate="{StaticResource ResourceKey=objectTemplate}">
<StackPanel Orientation="Horizontal" Margin="10,0,0,0">
<CheckBox Foreground="White" IsChecked="{Binding IsToBeExported}" VerticalAlignment="Center" />
<Label Style="{StaticResource baseStyle}" Content="{Binding Path=Name}" VerticalAlignment="Center" />
</StackPanel>
</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
The tree structure is like below. Each Parent can have any number of children & each Child can have any number of Grandchildren. Multiple selection is allowed too.
Parent
-Child
--Grandchild
I have checkboxes for all levels. I am not getting how to access its nodes individually and also how to use the tree data.
In my VM class, I set the datacontext of this TreeView to a 3 class list like below:
public class MProject
{
public string Name { get; set; }
public bool IsToBeExported { get; set; }
public List<MWorkObject> ObjectList { get; set; }
}
public class MWorkObject
{
public string Name { get; set; }
public bool IsToBeExported { get; set; }
public List<MLayer> LayersList { get; set; }
}
public class MLayer
{
public string Name { get; set; }
public bool IsToBeExported { get; set; }
}
My requirement is:
Selecting the parent should select all its child and grandchild.
How to identify in the code which item is selected ? Need it to do further processing.
Please help.

You need to implement INotifyPropertyChanged for your classes. Then
in setter of IsToBeExported in MProject handle all children (set
IsToBeExported to what you need). The binding makes the change
visible in tree
if IsToBeExported set to true, then it is selected
Example:
public class ViewBase :INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
protected void NotifyPropertyChanged(string info)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(info));
}
}
public class MProject : ViewBase
{
public string Name
{
get
{
return _name;
}
set
{
if (value != _name)
{
_name = value;
NotifyPropertyChanged(nameof(Name));
}
}
}
private string _name;
...
}

WPF - MVVM : How to Check/Uncheck all Items in a ListView

I have the following requirements:
Window will show a ListView with multiple items.
User should be able to check (Checkbox) any item.
a) If one item, all items should be unchecked and disabled.
b) If checked item is unchecked, than all items should be enabled.
As of now, I have the following incomplete code.
MainWindow XAML:
<Window x:Class="WpfApplication4.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="520.149" Width="732.463">
<Window.Resources>
<ResourceDictionary Source="MainWindowResource.xaml" />
</Window.Resources>
<Grid>
<ListView x:Name="myListBox" ItemTemplate="{StaticResource OfferingTemplate}">
<ListView.ItemsPanel>
<ItemsPanelTemplate>
<UniformGrid Columns="3" VerticalAlignment="Top"/>
</ItemsPanelTemplate>
</ListView.ItemsPanel>
</ListView>
</Grid>
</Window>
DataTemplete for ListView:
<DataTemplate x:Key="OfferingTemplate">
<StackPanel>
<Grid IsEnabled="{Binding IsEnabled}">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="8"></ColumnDefinition>
<ColumnDefinition Width="120"></ColumnDefinition>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="40"></RowDefinition>
<RowDefinition Height="50"></RowDefinition>
<RowDefinition Height="30"></RowDefinition>
</Grid.RowDefinitions>
<Rectangle Grid.Column="0" Grid.RowSpan="3" Fill="#F4CA16" />
<Label
Grid.Column="1"
Grid.Row="0"
Content="{Binding Title}"
FontSize="18" FontWeight="Bold"
Margin="0,0,0,0" />
<TextBlock
Grid.Column="1"
Grid.Row="1"
FontSize="10"
Text="{Binding Description}"
Foreground="Black"
TextWrapping="WrapWithOverflow"
Margin="5,0,0,0" />
<CheckBox
Grid.Column="1"
Grid.Row="2"
FontSize="14"
IsChecked="{Binding IsSelected}"
VerticalAlignment="Bottom"
Margin="5,0,0,0">
<TextBlock Text="Select" Margin="0,-2,0,0"/>
</CheckBox>
</Grid>
</StackPanel>
</DataTemplate>
Model:
class MyModel
{
public string Title { get; set; }
public string Description { get; set; }
public bool IsSelected { get; set; }
public bool IsEnabled { get; set; }
}
ViewModel:
class MyViewModel : INotifyPropertyChanged
{
private MyModel offering;
public MyViewModel()
{
offering = new MyModel();
}
public int ID { get; set; }
public string Title
{
get { return offering.Title; }
set
{
offering.Title = value;
RaisePropertyChanged("Title");
}
}
public string Description
{
get { return offering.Description; }
set
{
offering.Description = value;
RaisePropertyChanged("Description");
}
}
public bool IsSelected
{
get { return offering.IsSelected; }
set
{
offering.IsSelected = value;
RaisePropertyChanged("IsSelected");
}
}
public bool IsEnabled
{
get { return offering.IsEnabled; }
set
{
offering.IsEnabled = value;
RaisePropertyChanged("IsEnabled");
}
}
public event PropertyChangedEventHandler PropertyChanged;
private void RaisePropertyChanged(string propertyName)
{
var handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(propertyName));
}
}
}

This is an interesting question. Since the action you want applies to all items in the list, this logic should in list class level. Your MyViewModel class is fine. You need add some logic in your list class and XAML but thanks to Prism, it is quite easy.
The list class (not shown in your post) Contains:
public ObservableCollection<MyViewModel> MyItems { get; set; } //Binding to ItemsSource
private ICommand _selectCommand;
public ICommand SelectCommand
{
get { return _selectCommand ?? (_selectCommand = new DelegateCommand<MyViewModel>(DoSelect)); }
}
private void DoSelect(MyViewModel myViewModel)
{
foreach(var item in MyItems)
if (item != myViewModel)
{
item.IsSelected = false;
item.IsEnabled = false;
}
}
private ICommand _unselectCommand;
public ICommand UnselectCommand
{
get { return _unselectCommand ?? (_unselectCommand = new DelegateCommand<MyViewModel>(DoUnselect)); }
}
private void DoUnselect(MyViewModel myViewModel)
{
foreach (var item in MyItems)
if (item != myViewModel)
{
item.IsEnabled = true;
}
}
There are two commands, one for selecting and the other for unselecting. The magic is on XAML:
<ListView ItemsSource="{Binding Path=MyItems}" x:Name="listView">
<ListView.ItemTemplate>
<DataTemplate>
<CheckBox IsChecked="{Binding Path=IsSelected}" IsEnabled="{Binding Path=IsEnabled}">
<i:Interaction.Triggers>
<i:EventTrigger EventName="Checked">
<i:InvokeCommandAction Command="{Binding ElementName=listView, Path=DataContext.SelectCommand}"
CommandParameter="{Binding}"/>
</i:EventTrigger>
<i:EventTrigger EventName="Unchecked">
<i:InvokeCommandAction Command="{Binding ElementName=listView, Path=DataContext.UnselectCommand}"
CommandParameter="{Binding}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
</CheckBox>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
Using Prism's triggers, you can map CheckBox's Checked and Unchecked event to your list view model's commands and passing the item view model as parameter.
It is working perfectly but one thing is annoying, that setting item's IsSelected is separate. When you check a CheckBox, the item behind is set to true through DataBinding but all others are set through parent view model. If your post is all your requirement, you can remove IsChecked binding and put the logic of setting one IsSelected inside list view model, which looks clenaer and easier to write test code.

Retrieving bound object on node from TreeView

I'm not an expert in WPF so forgive me if I am wording my question weirdly. I'd be more than happy to elaborate if anything doesn't make sense.
I have a treeview that binds an observablecollection of a class. When my program launches, I read every C sourcecode files at a particular destination, store its name and filepath in the class mentioned.
Here is my XAML:
<TreeView Name="ProgramTree" ItemsSource="{Binding ProgramItemCollection}"
cal:Message.Attach="[Event PreviewMouseRightButtonDown] = [Action TestRight($dataContext,$eventArgs)];
[Event PreviewMouseDoubleClick] = [Action NodeDoubleClick($dataContext,$eventArgs)]">
<TreeView.Resources>
<!--DataTemplate for Program Nodes (Top) and binds FileItemNodes-->
<HierarchicalDataTemplate DataType="{x:Type my:ProgramItem}"
ItemsSource="{Binding FileItemCollection}">
<Border Width="100" BorderBrush="RoyalBlue"
Background="RoyalBlue" BorderThickness="1"
CornerRadius="2" Margin="2" Padding="2" >
<StackPanel Orientation="Horizontal">
<Image Style="{StaticResource IconStyle}" Margin="2" Source="{StaticResource FolderIcon}" />
<TextBlock Margin="2" Text="{Binding ProgramName}"
Foreground="White" FontWeight="Bold"/>
</StackPanel>
</Border>
</HierarchicalDataTemplate>
<!--DataTemplate for File Nodes (Subnodes of Program Nodes)-->
<HierarchicalDataTemplate DataType="{x:Type my:FileItem}">
<Border Width="80" Background="LightBlue" CornerRadius="2" Margin="1" >
<StackPanel Orientation="Horizontal">
<Image Margin="2" />
<TextBlock Margin="2" Text="{Binding NodeName}" />
</StackPanel>
</Border>
</HierarchicalDataTemplate>
</TreeView.Resources>
Codebehind:
public class FileItem
{
public string NodeName { get; set; }
public string FullName { get; set; }
public string Extension { get; set; }
}
public class ProgramItem : PropertyChangedBase
{
private ObservableCollection<FileItem> fileItemCollection;
...
What I now want to do is hook a double click event on the node and open the relevant file.
public void NodeDoubleClick(object sender, MouseButtonEventArgs e)
{
TreeViewItem treeViewItem = VisualUpwardSearch(e.OriginalSource as DependencyObject);
if (treeViewItem != null)
{
//Open file
}
}
private static TreeViewItem VisualUpwardSearch(DependencyObject source)
{
while (source != null && !(source is TreeViewItem))
source = VisualTreeHelper.GetParent(source);
return source as TreeViewItem;
}
I can retrieve the double clicked node (treeviewitem) without a problem. The problem is I want to retrieve an object of FileItem from the node I double clicked to access the filepath property. Is this possible at all?

It is possible by resolving the DataContext of the TreeViewItem:
FileItem fileItem = (treeViewItem.DataContext as FileItem);
A more elegant way would be to use MouseInput Bindings and a Command in your FileItem class.
In your Datatemplate for FileItem:
<StackPanel Orientation="Horizontal">
<StackPanel.InputBindings>
<MouseBinding MouseAction="LeftDoubleClick"
Command="{Binding OpenFileCommand}" />
</StackPanel.InputBindings>
<Image Margin="2" />
<TextBlock Margin="2" Text="{Binding NodeName}" />
</StackPanel>
In your FileItem:
public class FileItem
{
public FileItem()
{
this.OpenFileCommand
= new SimpleCommand(()=> Process.StartNew(this.FullName));
}
public string NodeName { get; set; }
public string FullName { get; set; }
public string Extension { get; set; }
public ICommand OpenFileCommand { get; set;}
}
P.S.: If you are not used to WPF's Commands, a basic implementation of a simple ICommand could be:
public class SimpleCommand : System.Windows.Input.ICommand
{
public SimpleCommand(Action action)
{
this.Action = action;
}
public Action Action { get; set; }
public bool CanExecute(object parameter)
{
return (this.Action != null);
}
public event EventHandler CanExecuteChanged;
public void Execute(object parameter)
{
if (this.Action != null)
{
this.Action();
}
}
}
Commands are much more effective for such szenarios. You dont need to walk the visual Tree and you do not need code behind at all.

Check the DataContext property of TreeViewItem and try to cast it to FileItem type.
Also you can define the template for FileItem as simple DataTemplate, not the HierarchicalDataTemplate.