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Search found 54 results on 3 pages for 'treeviewitem'.

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  • wpf observableCollection

    - by Asha
    I have an ObservableCollection which is dataContext for my treeview when I try to remove an Item from ObservableCollection I will get an error that Object reference not set to an instance of an object . can you please tell me why this error is happening and what is the solution thanks EDIT 1: The code is something like : class MyClass : INotifyPropertyChanged { //my class code here } public partial class UC_myUserControl : UserControl { private ObservableCollection<MyClass> myCollection = new ObservableCollection<MyClass>(); private void UserControl_Loaded(object sender, RoutedEventArgs e) { myCollection.add(new myClass); myTreeView.DataContext = myCollection ; } private void deleteItem() { myCollection.RemoveAt(0); //after removing I get error Which I guess should be something related //to interface update but I don't know how can I solve it } } Exception Detail : System.NullReferenceException was unhandled Message="Object reference not set to an instance of an object." Source="PresentationFramework" EDIT 3: I have a style which is for my treeitem to keep the treeitems expanded <Style TargetType="TreeViewItem"> <Setter Property="IsExpanded" Value="True" /> </Style> and with commenting this part I wont get any error !!! Now I want to change my question to why having this style is causing error ?

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  • WPF MVVM TreeView item source losing context after command

    - by user3955716
    I have a treeview which contains files, every view model holds an item source which is an ObservableCollection with files items: public ObservableCollection<CMItemFileNode> SubItemNode On each item i have context menu options (Delete, Execute..). If i move from one viewModel to another the ObservableCollection of files updated correctly and presented correctly but, when i perform a context menu command like delete file item, the command execute good but when i move to another view model (which holds SubItemNode ObservableCollection of is own) after the command executed the WPF still thinks i'm in the last view model i was in and not the one i'm really on. Very important to mention is that when i update to .net 4.5 (which unfortunantly i can't do) everything is ok and the ObservableCollection addresses the correct view model. Here is the treeView: <TreeView x:Name="Files" Margin="0,5,5,0" Grid.Row="6" Grid.Column="2" ItemsSource="{Binding SubItemNode}" HorizontalAlignment="Stretch" HorizontalContentAlignment="Stretch" VerticalAlignment="Stretch" Height="300" Grid.RowSpan="6" Width="300" dd:DragDrop.IsDragSource="True" dd:DragDrop.IsDropTarget="True" dd:DragDrop.DropHandler="{Binding}" dd:DragDrop.UseDefaultDragAdorner="True"> <TreeView.Resources> <Style TargetType="{x:Type TreeView}"> <Setter Property="local:CMTreeViewFilesBehavior.IsTreeViewFilesBehavior" Value="True"/> </Style> <Style TargetType="{x:Type TreeViewItem}"> <Setter Property="IsSelected" Value="{Binding IsSelected}" /> <Setter Property="local:CMTreeViewFilesItemBehavior.IsTreeViewFilesItemBehavior" Value="True"/> </Style> <SolidColorBrush x:Key="{x:Static SystemColors.HighlightBrushKey}" Color="Transparent" /> <SolidColorBrush x:Key="{x:Static SystemColors.HighlightTextBrushKey}" Color="Black" /> </TreeView.Resources> <TreeView.ContextMenu> <ContextMenu> <MenuItem Header="View File" Command="{Binding ExecuteFileCommand}" /> <Separator /> <MenuItem Header="Delete all" Command="{Binding DeleteAllFilesCommand}" /> <MenuItem Header="Delete selected" Command="{Binding DeleteSelectedFilesCommand}" /> </ContextMenu> </TreeView.ContextMenu> <TreeView.ItemTemplate> <HierarchicalDataTemplate ItemsSource="{Binding SubItemNode}" > <Grid> <Grid.ColumnDefinitions> <ColumnDefinition Width="Auto"/> <ColumnDefinition Width="*"/> </Grid.ColumnDefinitions> <Image Grid.Column="0" Margin="2" Width="32" Height="18" Source="{Binding Path=Icon}" HorizontalAlignment="Left" VerticalAlignment="Center" /> <TextBlock Text="{Binding Path=Name}" Grid.Column="1" Margin="2" VerticalAlignment="Center" Foreground="{Binding Path=Status, Converter={StaticResource ItemFileStatusToColor}}" FontWeight="{Binding Path=IsSelected, Converter={StaticResource BoolToFontWidth}}"/> </Grid> </HierarchicalDataTemplate> </TreeView.ItemTemplate> </TreeView> Am I doing somthing wrong? and why in .net 4.5 it works well ?

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  • Bound Command not firing on another viewModel? What Am I doing wrong?

    - by devnet247
    Hi I cannot seem to bind a command to a button.I have a treeview on the left showing Country City etc.. And I tabcontrol on the right. do I This uses 4 viewModels rootviewModel-ContinentViewModel-CountryViewModel-CityViewModel What I am building is based on http://www.codeproject.com/KB/WPF/TreeViewWithViewModel.aspx Now on one of the tabs I have a Toolbar with a button "TestButton" that I have mapped in zaml. This does not fire! The reason is not firing is because I m binding the RootViewModel but the command that is bound in zaml is in the cityViewModel. How Do I pass the datacontext from one view to the other? or how do I make the button fire. I need the command to be in the cityViewModel. Any Suggestions on how I bind it? View "WorldExplorerView" where I bind the main DataContext public partial class WorldExplorerView { public WorldExplorerView() { InitializeComponent(); var continents = Database.GetContinents(); var rootViewModel = new RootViewModel(continents); DataContext = rootViewModel; } } CityViewModel public class CityViewModel : TreeViewItemViewModel { private City _city; private RelayCommand _testCommand; public CityViewModel(City city, CountryViewModel countryViewModel):base(countryViewModel,false) { _city = city; } Properties etc...... public ICommand TestCommand { get { if(_testCommand==null) { _testCommand = new RelayCommand(param => GetTestCommand(), param => CanCallTestCommand); ; } return _testCommand; } } protected bool CanCallTestCommand { get { return true; } } private static void GetTestCommand() { MessageBox.Show("It works"); } } ZAML <DockPanel> <DockPanel LastChildFill="True"> <Label DockPanel.Dock="top" Content="Title " HorizontalAlignment="Center"></Label> <StatusBar DockPanel.Dock="Bottom"> <StatusBarItem Content="Status Bar" ></StatusBarItem> </StatusBar> <Grid DockPanel.Dock="Top"> <Grid.ColumnDefinitions> <ColumnDefinition/> <ColumnDefinition Width="Auto"/> <ColumnDefinition Width="2*"/> </Grid.ColumnDefinitions> <TreeView Name="tree" ItemsSource="{Binding Continents}"> <TreeView.ItemContainerStyle> <Style TargetType="{x:Type TreeViewItem}"> <Setter Property="IsExpanded" Value="{Binding IsExpanded,Mode=TwoWay}"/> <Setter Property="IsSelected" Value="{Binding IsSelected,Mode=TwoWay}"/> <Setter Property="FontWeight" Value="Normal"/> <Style.Triggers> <Trigger Property="IsSelected" Value="True"> <Setter Property="FontWeight" Value="Bold"></Setter> </Trigger> </Style.Triggers> </Style> </TreeView.ItemContainerStyle> <TreeView.Resources> <HierarchicalDataTemplate DataType="{x:Type ViewModels:ContinentViewModel}" ItemsSource="{Binding Children}"> <StackPanel Orientation="Horizontal"> <Image Width="16" Height="16" Margin="3,0" Source="Images\Continent.png"/> <TextBlock Text="{Binding ContinentName}"/> </StackPanel> </HierarchicalDataTemplate> <HierarchicalDataTemplate DataType="{x:Type ViewModels:CountryViewModel}" ItemsSource="{Binding Children}"> <StackPanel Orientation="Horizontal"> <Image Width="16" Height="16" Margin="3,0" Source="Images\Country.png"/> <TextBlock Text="{Binding CountryName}"/> </StackPanel> </HierarchicalDataTemplate> <DataTemplate DataType="{x:Type ViewModels:CityViewModel}" > <StackPanel Orientation="Horizontal"> <Image Width="16" Height="16" Margin="3,0" Source="Images\City.png"/> <TextBlock Text="{Binding CityName}"/> </StackPanel> </DataTemplate> </TreeView.Resources> </TreeView> <GridSplitter Grid.Row="0" Grid.Column="1" Background="LightGray" Width="5" HorizontalAlignment="Stretch" VerticalAlignment="Stretch"/> <Grid Grid.Column="2" Margin="5" > <TabControl> <TabItem Header="Demo"> <DockPanel LastChildFill="True"> <ToolBar DockPanel.Dock="Top"> <!-- DOES NOT WORK--> <Button Name="btnTest" Command="{Binding TestCommand}" Content="Press me see if works"></Button> </ToolBar> <TextBox></TextBox> </DockPanel> </TabItem> <TabItem Header="Details" DataContext="{Binding Path=SelectedItem.City, ElementName=tree, Mode=OneWay}"> <StackPanel > <TextBlock VerticalAlignment="Center" FontSize="12" Text="{Binding CityName}"/> <TextBlock VerticalAlignment="Center" FontSize="12" Text="{Binding Area}"/> <TextBlock VerticalAlignment="Center" FontSize="12" Text="{Binding Population}"/> <TextBlock VerticalAlignment="Center" FontSize="12" Text="{Binding CityDetailsInfo.ClubsCount}"/> <TextBlock VerticalAlignment="Center" FontSize="12" Text="{Binding CityDetailsInfo.PubsCount}"/> </StackPanel> </TabItem> </TabControl> </Grid> </Grid> </DockPanel> </DockPanel>

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  • treeview binding wpf cannot bind nested property in a class

    - by devnet247
    Hi all New to wpf and therefore struggling a bit. I am putting together a quick demo before we go for the full implementation I have a treeview on the left with Continent Country City structure when a user select the city it should populate some textboxes in a tabcontrol on the right hand side I made it sort of work but cannot make it work with composite objects. In a nutshell can you spot what is wrong with my zaml or code. Why is not binding to a my CityDetails.ClubsCount or CityDetails.PubsCount? What I am building is based on http://www.codeproject.com/KB/WPF/TreeViewWithViewModel.aspx Thanks a lot for any suggestions or reply DataModel public class City { public City(string cityName) { CityName = cityName; } public string CityName { get; set; } public string Population { get; set; } public string Area { get; set; } public CityDetails CityDetailsInfo { get; set; } } public class CityDetails { public CityDetails(int pubsCount,int clubsCount) { PubsCount = pubsCount; ClubsCount = clubsCount; } public int ClubsCount { get; set; } public int PubsCount { get; set; } } ViewModel public class CityViewModel : TreeViewItemViewModel { private City _city; private RelayCommand _testCommand; public CityViewModel(City city, CountryViewModel countryViewModel):base(countryViewModel,false) { _city = city; } public string CityName { get { return _city.CityName; } } public string Area { get { return _city.Area; } } public string Population { get { return _city.Population; } } public City City { get { return _city; } set { _city = value; } } public CityDetails CityDetailsInfo { get { return _city.CityDetailsInfo; } set { _city.CityDetailsInfo = value; } } } XAML <DockPanel> <DockPanel LastChildFill="True"> <Label DockPanel.Dock="top" Content="Title " HorizontalAlignment="Center"></Label> <StatusBar DockPanel.Dock="Bottom"> <StatusBarItem Content="Status Bar" ></StatusBarItem> </StatusBar> <Grid DockPanel.Dock="Top"> <Grid.ColumnDefinitions> <ColumnDefinition/> <ColumnDefinition Width="Auto"/> <ColumnDefinition Width="2*"/> </Grid.ColumnDefinitions> <TreeView Name="tree" ItemsSource="{Binding Continents}"> <TreeView.ItemContainerStyle> <Style TargetType="{x:Type TreeViewItem}"> <Setter Property="IsExpanded" Value="{Binding IsExpanded,Mode=TwoWay}"/> <Setter Property="IsSelected" Value="{Binding IsSelected,Mode=TwoWay}"/> <Setter Property="FontWeight" Value="Normal"/> <Style.Triggers> <Trigger Property="IsSelected" Value="True"> <Setter Property="FontWeight" Value="Bold"></Setter> </Trigger> </Style.Triggers> </Style> </TreeView.ItemContainerStyle> <TreeView.Resources> <HierarchicalDataTemplate DataType="{x:Type ViewModels:ContinentViewModel}" ItemsSource="{Binding Children}"> <StackPanel Orientation="Horizontal"> <Image Width="16" Height="16" Margin="3,0" Source="Images\Continent.png"/> <TextBlock Text="{Binding ContinentName}"/> </StackPanel> </HierarchicalDataTemplate> <HierarchicalDataTemplate DataType="{x:Type ViewModels:CountryViewModel}" ItemsSource="{Binding Children}"> <StackPanel Orientation="Horizontal"> <Image Width="16" Height="16" Margin="3,0" Source="Images\Country.png"/> <TextBlock Text="{Binding CountryName}"/> </StackPanel> </HierarchicalDataTemplate> <DataTemplate DataType="{x:Type ViewModels:CityViewModel}" > <StackPanel Orientation="Horizontal"> <Image Width="16" Height="16" Margin="3,0" Source="Images\City.png"/> <TextBlock Text="{Binding CityName}"/> </StackPanel> </DataTemplate> </TreeView.Resources> </TreeView> <GridSplitter Grid.Row="0" Grid.Column="1" Background="LightGray" Width="5" HorizontalAlignment="Stretch" VerticalAlignment="Stretch"/> <Grid Grid.Column="2" Margin="5" > <TabControl> <TabItem Header="Details" DataContext="{Binding Path=SelectedItem.City, ElementName=tree, Mode=OneWay}"> <StackPanel > <TextBlock VerticalAlignment="Center" FontSize="12" Text="{Binding CityName}"/> <TextBlock VerticalAlignment="Center" FontSize="12" Text="{Binding Area}"/> <TextBlock VerticalAlignment="Center" FontSize="12" Text="{Binding Population}"/> <!-- DONT WORK WHY--> <TextBlock VerticalAlignment="Center" FontSize="12" Text="{Binding SelectedItem.CityDetailsInfo.ClubsCount}"/> <TextBlock VerticalAlignment="Center" FontSize="12" Text="{Binding SelectedItem.CityDetailsInfo.PubsCount}"/> </StackPanel> </TabItem> </TabControl> </Grid> </Grid> </DockPanel> </DockPanel>

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