On initialization of main window i set DataContext to usercontrol and on this usercontrol i have an event which suppose to change datacontext of main window to another usercontrol but nothing happens.
Here is xaml for main window:
</Window.Resources>
<Grid>
<ContentControl Content="{Binding}" Width="auto" Height="auto" />
</Grid>
Here is C# for main window:
public MainWindow()
{
InitializeComponent();
DataContext = new LogInViewModel();
}
Here is xaml for LogInUserControl:
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<StackPanel Grid.Column="1" Grid.Row="1">
<StackPanel Orientation="Horizontal" HorizontalAlignment="Center" Width="250">
<StackPanel Width="125">
<TextBlock Text="Email:" Margin="5,0,5,0" Width="auto"/>
</StackPanel>
<StackPanel Width="125">
<TextBlock Text="Password:" Margin="5,0,0,0" Width="auto"/>
</StackPanel>
</StackPanel>
<StackPanel Orientation="Horizontal" HorizontalAlignment="Center">
<TextBox Margin="5,0,5,0" HorizontalAlignment="Center" Height="23" TextWrapping="Wrap" VerticalAlignment="Top" Width="120"/>
<PasswordBox Margin="0,0,0,5" HorizontalAlignment="Center" Height="23" VerticalAlignment="Top" Width="120"/>
</StackPanel>
<Button Content="Log In" Margin="0,0,0,5" HorizontalAlignment="Center" VerticalAlignment="Top" Width="75"/>
</StackPanel>
<Grid Grid.Column="1" Grid.Row="1">
<StackPanel Orientation="Horizontal" HorizontalAlignment="Center">
<TextBlock Text="don't have account yet ?" HorizontalAlignment="Center" VerticalAlignment="Bottom" Margin="5"/>
<TextBlock Name="TBSignUp" Text="Sign Up" HorizontalAlignment="Center" VerticalAlignment="Bottom" Margin="5" PreviewMouseLeftButtonDown="TextBlock_PreviewMouseLeftButtonDown" PreviewMouseLeftButtonUp="TextBlock_PreviewMouseLeftButtonUp" Foreground="#FF0B36F5"/>
</StackPanel>
</Grid>
</Grid>
and here is C# for LogInUserControl:
public partial class LogInView : UserControl
{
string BlackForeground = "#FF000000" ;
string OriginalForeground = "#FF0B36F5";
public LogInView()
{
InitializeComponent();
}
private void TextBlock_PreviewMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
TBSignUp.Foreground = new SolidColorBrush((Color)ColorConverter.ConvertFromString(OriginalForeground));
DataContext = new RegisterView();
}
private void TextBlock_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
TBSignUp.Foreground = new SolidColorBrush((Color)ColorConverter.ConvertFromString(BlackForeground));
}
}
In WPF you can get a shell (first) window from anywhere:
System.Windows.Window shell = System.Windows.Application.Current.MainWindow;
OR
Application.Current.Windows[0];
but I recommend passing the reference if needed.
look at the MVVM pattern, you need to implement property change notification in your view model class to bind properties.
You need to set it on App.xaml.cs.
App.xaml.cs:
public class App : Application
{
protected override void OnStartup(StartupEventArgs e)
{
MainWindow window=new MainWindow();
LogInViewModel vm=new LogInViewModel(); // You need to set DataContext...
window.DataContext=vm; // ...before showing up the window.
window.Show();
}
}
In the ViewModel patterns that I found from research, usage is before DataContext, after Show();.
I hope that solves your problem.
Related
When i try to set VirtualizationMode on my ListView to Recycling I get the error from the title:
Cannot change the VirtualizationMode attached property on an
ItemsControl after Measure is called on the ItemsHost panel.
I am trying to set the attached property programmatically but when I try to define the VirtualizationMode in XAML designer throws the same error from the title. Anyone had similar problems like this?
My view in XAML is:
<Window x:Class="FinalVirtualizationApp.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:FinalVirtualizationApp"
mc:Ignorable="d"
Title="MainWindow" Height="900" Width="800"
xmlns:materialDesign="http://materialdesigninxaml.net/winfx/xaml/themes"
TextElement.Foreground="{DynamicResource MaterialDesignBody}"
TextElement.FontWeight="Regular"
TextElement.FontSize="13"
TextOptions.TextFormattingMode="Ideal"
TextOptions.TextRenderingMode="Auto"
Background="{DynamicResource MaterialDesignPaper}"
FontFamily="{DynamicResource MaterialDesignFont}">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition />
</Grid.ColumnDefinitions>
<GroupBox Grid.Row="0" Header="UI virtualization options">
<Grid>
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<CheckBox Content="UI virtualization" VerticalAlignment="Center" IsChecked="{Binding IsUIVirtualization}"/>
<Grid Grid.Column="1">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<Label Content="Container Recycling:" VerticalAlignment="Center"/>
<ComboBox Grid.Column="1" VerticalAlignment="Center" SelectedValue="{Binding ContainerRecyclingType}" SelectedValuePath="Content">
<ComboBoxItem>Recycling</ComboBoxItem>
<ComboBoxItem>Standard</ComboBoxItem>
</ComboBox>
</Grid>
<CheckBox Content="Deferred scrolling" Grid.Row="1" VerticalAlignment="Center" IsChecked="{Binding IsDeferredScrolling}">
</CheckBox>
<Grid Grid.Row="1" Grid.Column="1">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="74*"/>
<ColumnDefinition Width="253*"/>
</Grid.ColumnDefinitions>
<Label Content="Scroll unit" VerticalAlignment="Center" Margin="0,0,0,1"/>
<ComboBox Grid.Column="1" VerticalAlignment="Center" SelectedValue="{Binding ScrollUnitType}" SelectedValuePath="Content" Grid.ColumnSpan="2" Margin="0,2,0,3">
<ComboBoxItem>Item</ComboBoxItem>
<ComboBoxItem>Pixel</ComboBoxItem>
</ComboBox>
</Grid>
</Grid>
</GroupBox>
<GroupBox Grid.Row="1" Header="Data virtualization">
<Grid>
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<GroupBox Header="ItemsProvider">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<StackPanel Orientation="Horizontal">
<Label Content="Number of Items: "/>
<TextBox Width="60" Text="{Binding NumberOfItems}"/>
</StackPanel>
<StackPanel Grid.Column="1" Orientation="Horizontal">
<Label Content="Fetch delay(ms): "/>
<TextBox Width="60" Text="{Binding FetchDelay}"/>
</StackPanel>
</Grid>
</GroupBox>
<GroupBox Grid.Row="1" Header="Collection">
<StackPanel>
<StackPanel Orientation="Horizontal" Margin="0,2,0,0">
<TextBlock Text="Type:" Margin="5" TextAlignment="Right" VerticalAlignment="Center"/>
<RadioButton x:Name="rbNormal" GroupName="rbGroup" Margin="5" Content="List(T)" VerticalAlignment="Center" Command="{Binding CollectionTypeChangeCommand}" CommandParameter="List"/>
<RadioButton x:Name="rbVirtualizing" GroupName="rbGroup" Margin="5" Content="VirtualizingList(T)" VerticalAlignment="Center" Command="{Binding CollectionTypeChangeCommand}" CommandParameter="VirtualizingList"/>
<RadioButton x:Name="rbAsync" GroupName="rbGroup" Margin="5" Content="AsyncVirtualizingList(T)" VerticalAlignment="Center" Command="{Binding CollectionTypeChangeCommand}" CommandParameter="AsyncVirtualizingList"/>
</StackPanel>
<StackPanel Orientation="Horizontal" Margin="0,2,0,0">
<TextBlock Text="Page size:" Margin="5" TextAlignment="Right" VerticalAlignment="Center"/>
<TextBox x:Name="tbPageSize" Margin="5" Text="{Binding PageSize}" Width="60" VerticalAlignment="Center"/>
<TextBlock Text="Page timeout (s):" Margin="5" TextAlignment="Right" VerticalAlignment="Center"/>
<TextBox x:Name="tbPageTimeout" Margin="5" Text="{Binding PageTimeout}" Width="60" VerticalAlignment="Center"/>
</StackPanel>
</StackPanel>
</GroupBox>
</Grid>
</GroupBox>
<StackPanel Orientation="Horizontal" Grid.Row="2">
<TextBlock Text="Memory Usage:" Margin="5" VerticalAlignment="Center"/>
<TextBlock x:Name="tbMemory" Margin="5" Width="80" Text="{Binding MemoryUsage}" VerticalAlignment="Center"/>
<Button Content="Refresh" Margin="5" Width="100" VerticalAlignment="Center" Command="{Binding RefreshCommand}"/>
</StackPanel>
<ListView Grid.Row="3" Name="lvItems">
<ListView.ItemTemplate>
<DataTemplate>
<Expander Header="{Binding DeviceName}">
<StackPanel>
</StackPanel>
</Expander>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</Grid>
</Window>
And i try to set the VirtualizationMode here:
public void SetUIVirtualizationOptions()
{
listView.SetValue(VirtualizingStackPanel.IsVirtualizingProperty, IsUIVirtualization);
listView.SetValue(ScrollViewer.IsDeferredScrollingEnabledProperty, IsDeferredScrolling);
if(ContainerRecyclingType == "Recycling")
listView.SetValue(VirtualizingStackPanel.VirtualizationModeProperty, VirtualizationMode.Recycling);
else
listView.SetValue(VirtualizingStackPanel.VirtualizationModeProperty, VirtualizationMode.Standard);
if (ScrollUnitType == "Item")
listView.SetValue(VirtualizingPanel.ScrollUnitProperty, ScrollUnit.Item);
else
listView.SetValue(VirtualizingPanel.ScrollUnitProperty, ScrollUnit.Pixel);
}
Edit: My Window code behind where i pass the listview to viewmodel is:
{
public MainWindow()
{
InitializeComponent();
DataContext = new MainWindowViewModel(lvItems);
}
}
And the viewmodel part of the code (minus getters and setters for less space taken):
public class MainWindowViewModel : BindableBase
{
#region private fields
private ListView listView;
private bool isUIVirtualization;
private bool isDeferredScrolling;
private string containerRecyclingType;
private string scrollUnitType;
private int numberOfItems;
private int fetchDelay;
private string collectionType;
private int pageSize;
private int pageTimeout;
private string memoryUsage;
private DemoItemProvider itemsProvider;
#endregion
#region commands
public RelayCommand<string> CollectionTypeChangeCommand { get; set; }
public RelayCommand RefreshCommand { get; set; }
public RelayCommand<string> ContainerRecyclingTypeChangeCommand { get; set; }
public RelayCommand<string> ScrollUnitTypeChangeCommand { get; set; }
#endregion
public MainWindowViewModel(ListView lvItems)
{
this.listView = lvItems;
PageSize = 100;
PageTimeout = 30;
NumberOfItems = 1000000;
FetchDelay = 1000;
CollectionTypeChangeCommand = new RelayCommand<string>(CollectionTypeChangeFunc);
RefreshCommand = new RelayCommand(RefreshFunc);
ContainerRecyclingTypeChangeCommand = new RelayCommand<string>(ContainerRecyclingTypeChangeFunc);
ScrollUnitTypeChangeCommand = new RelayCommand<string>(ScrollUnitTypeChangeFunc);
// use a timer to periodically update the memory usage
DispatcherTimer timer = new DispatcherTimer();
timer.Interval = new TimeSpan(0, 0, 1);
timer.Tick += timer_Tick;
timer.Start();
}
private void timer_Tick(object sender, EventArgs e)
{
MemoryUsage = string.Format("{0:0.00} MB", GC.GetTotalMemory(true) / 1024.0 / 1024.0);
}
#region command methods
public void CollectionTypeChangeFunc(string type)
{
CollectionType = type;
}
public void RefreshFunc()
{
SetUIVirtualizationOptions();
itemsProvider = new DemoItemProvider(NumberOfItems, FetchDelay);
if (collectionType == "List")
{
listView.ItemsSource = new List<DataItem>(itemsProvider.FetchRange(0, itemsProvider.FetchCount()));
}
else if (collectionType == "VirtualizingList")
{
listView.ItemsSource = new VirtualizingCollection<DataItem>(itemsProvider, pageSize);
}
else if (collectionType == "AsyncVirtualizingList")
{
listView.ItemsSource = new AsyncVirtualizingCollection<DataItem>(itemsProvider, pageSize, pageTimeout * 1000);
}
}
public void ContainerRecyclingTypeChangeFunc(string type)
{
ContainerRecyclingType = type;
}
public void ScrollUnitTypeChangeFunc(string type)
{
ScrollUnitType = type;
}
public void SetUIVirtualizationOptions()
{
listView.SetValue(VirtualizingStackPanel.IsVirtualizingProperty, IsUIVirtualization);
listView.SetValue(ScrollViewer.IsDeferredScrollingEnabledProperty, IsDeferredScrolling);
if(ContainerRecyclingType == "Recycling")
listView.SetValue(VirtualizingStackPanel.VirtualizationModeProperty, VirtualizationMode.Recycling);
else
listView.SetValue(VirtualizingStackPanel.VirtualizationModeProperty, VirtualizationMode.Standard);
if (ScrollUnitType == "Item")
listView.SetValue(VirtualizingPanel.ScrollUnitProperty, ScrollUnit.Item);
else
listView.SetValue(VirtualizingPanel.ScrollUnitProperty, ScrollUnit.Pixel);
}
#endregion
}
The code source for VirtualizingStackPanel indicates that this property can only be set before initialization of the panel:
/// <summary>
/// Attached property for use on the ItemsControl that is the host for the items being
/// presented by this panel. Use this property to modify the virtualization mode.
///
/// Note that this property can only be set before the panel has been initialized
/// </summary>
public static readonly DependencyProperty VirtualizationModeProperty =
DependencyProperty.RegisterAttached("VirtualizationMode", typeof(VirtualizationMode), typeof(VirtualizingStackPanel),
new FrameworkPropertyMetadata(VirtualizationMode.Standard));
You can indeed check this behavior later in the file:
//
// Set up info on first measure
//
if (HasMeasured)
{
VirtualizationMode oldVirtualizationMode = InRecyclingMode ? VirtualizationMode.Recycling : VirtualizationMode.Standard;
if (oldVirtualizationMode != virtualizationMode)
{
throw new InvalidOperationException(SR.Get(SRID.CantSwitchVirtualizationModePostMeasure));
}
}
else
{
HasMeasured = true;
}
and there is no way (according to source code) to set this HasMeasured property back to False unless you destroy and recreate the ListView.
It is so as the message says:
Your not allowed to _change the VirtualizationMode attached property
on an ItemsControl after Measure is called on the ItemsHost panel.
This means, that if ListView is already shown virtualizing mechanism being used and you are not allowed to change it.
If you set Visibility of ListView in XAML to Collapsed and set it only later to the Visible, then you can set the VirtualizationMode in code behind to wished value, but only once(so you can't change it after ListView become visible)!
private void Button_Click(object sender, RoutedEventArgs e)
{
listView.SetValue(VirtualizingStackPanel.VirtualizationModeProperty, VirtualizationMode.Recycling);
listView.Visibility = Visibility.Visible;
}
XAML:
<ListView x:Name="listView" ... Visibility="Collapsed">
Ok, I've been practicing with MVVM Pattern on UWP, now I've created an object Customer EditableCustomer which is my helper property between my view and my model at my VM.
if my four properties FirstName, LastName, Email and Phone arent nulls or emptys my savecommand button should enable.
but I havent been able to raise my property changes on my EditableCustomer so that way I could Raise my SaveCommand.RaiseCanExecuteChanged().
this is my code for my view:
<UserControl
x:Class="MVVMHeirarchiesDemo.Views.AddEditCustomerView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:MVVMHeirarchiesDemo.Views"
xmlns:viewmodel="using:MVVMHeirarchiesDemo.ViewModel"
xmlns:conv="using:MVVMHeirarchiesDemo.Converters"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
d:DesignHeight="300"
d:DesignWidth="400">
<UserControl.DataContext>
<viewmodel:AddEditCustomerViewModel/>
</UserControl.DataContext>
<UserControl.Resources>
<conv:ValidationMessageConverter x:Key="ValidationMessageConverter"/>
</UserControl.Resources>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Grid x:Name="grid1"
HorizontalAlignment="Left"
Margin="10,10,0,0"
VerticalAlignment="Top">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<TextBlock Text="First Name:"
Grid.Column="0"
Grid.Row="0"
HorizontalAlignment="Left"
VerticalAlignment="Center"
Margin="3"/>
<StackPanel Orientation="Vertical"
Grid.Column="1"
Grid.Row="0">
<TextBox x:Name="firstNameTextBox"
Text="{Binding EditableCustomer.FirstName, Mode=TwoWay}"
HorizontalAlignment="Left"
VerticalAlignment="Center"
Margin="3"
Height="23"
Width="120"/>
<TextBlock x:Name="firstNameErrorMessage"
Text="{Binding EditableCustomer.ValidationMessages[FirstName], Converter={StaticResource ValidationMessageConverter}}"
Width="{Binding Width, ElementName=firstNameTextBox, Mode=OneWay}"
TextWrapping="Wrap"/>
</StackPanel>
<TextBlock Text="Last Name:"
Grid.Column="0"
Grid.Row="1"
HorizontalAlignment="Left"
VerticalAlignment="Center"
Margin="3"/>
<StackPanel Orientation="Vertical"
Grid.Column="1"
Grid.Row="1">
<TextBox x:Name="lastNameTextBox"
Text="{Binding EditableCustomer.LastName, Mode=TwoWay}"
HorizontalAlignment="Left"
VerticalAlignment="Center"
Width="{Binding Width, ElementName=firstNameTextBox, Mode=OneWay}"
Height="{Binding Height, ElementName=firstNameTextBox, Mode=OneWay}"
Margin="3"/>
<TextBlock x:Name="lastNameErrorMessage"
Text="{Binding EditableCustomer.ValidationMessages[LastName], Converter={StaticResource ValidationMessageConverter}}"
Width="{Binding Width, ElementName=firstNameTextBox, Mode=OneWay}"
TextWrapping="Wrap"/>
</StackPanel>
<TextBlock Text="Email:"
Grid.Column="0"
Grid.Row="2"
HorizontalAlignment="Left"
VerticalAlignment="Center"
Margin="3"/>
<StackPanel Orientation="Vertical"
Grid.Column="1"
Grid.Row="2">
<TextBox x:Name="emailTextBox"
Text="{Binding EditableCustomer.Email, Mode=TwoWay}"
HorizontalAlignment="Left"
VerticalAlignment="Center"
Width="{Binding Width, ElementName=firstNameTextBox, Mode=OneWay}"
Height="{Binding Height, ElementName=firstNameTextBox, Mode=OneWay}"
Margin="3"/>
<TextBlock x:Name="emailErrorMessage"
Text="{Binding EditableCustomer.ValidationMessages[Email], Converter={StaticResource ValidationMessageConverter}}"
Width="{Binding Width, ElementName=firstNameTextBox, Mode=OneWay}"
TextWrapping="Wrap"/>
</StackPanel>
<TextBlock Text="Phone:"
Grid.Column="0"
Grid.Row="3"
HorizontalAlignment="Left"
VerticalAlignment="Center"
Margin="3"/>
<StackPanel Orientation="Vertical"
Grid.Column="1"
Grid.Row="3">
<TextBox x:Name="phoneTextBox"
Text="{Binding EditableCustomer.Phone, Mode=TwoWay}"
HorizontalAlignment="Left"
VerticalAlignment="Center"
Width="{Binding Width, ElementName=firstNameTextBox, Mode=OneWay}"
Height="{Binding Height, ElementName=firstNameTextBox, Mode=OneWay}"
Margin="3"/>
<TextBlock x:Name="phoneErrorMessage"
Text="{Binding EditableCustomer.ValidationMessages[Phone], Converter={StaticResource ValidationMessageConverter}}"
Width="{Binding Width, ElementName=firstNameTextBox, Mode=OneWay}"
TextWrapping="Wrap"/>
</StackPanel>
</Grid>
<Grid Grid.Row="1">
<StackPanel Orientation="Horizontal">
<Button x:Name="saveCommandButton"
Content="Save"
Command="{Binding SaveCommand}"
HorizontalAlignment="Left"
VerticalAlignment="Top"
Margin="25,5,0,0"
Width="75"/>
<Button x:Name="addCommandButton"
Content="Add"
Command="{Binding SaveCommand}"
HorizontalAlignment="Left"
VerticalAlignment="Top"
Margin="25,5,0,0"
Width="{Binding Width, ElementName=saveCommandButton, Mode=OneWay}"/>
<Button x:Name="cancelCommandButton"
Content="Cancel"
Command="{Binding CancelCommand}"
HorizontalAlignment="Left"
VerticalAlignment="Center"
Margin="25,5,0,0"
Width="{Binding Width, ElementName=saveCommandButton, Mode=OneWay}"/>
</StackPanel>
</Grid>
</Grid>
As you can see at my textboxes the text property are bind to my EditableCustomer.(propertyName)
my ViewModel is this one:
public class AddEditCustomerViewModel : BindableBase
{
public AddEditCustomerViewModel()
{
CancelCommand = new MyCommand(OnCancel);
SaveCommand = new MyCommand(OnSave, CanSave);
EditableCustomer = new Customer();
}
private Customer _editableCustomer;
public Customer EditableCustomer
{
get
{
return _editableCustomer;
}
set
{
SetProperty(ref _editableCustomer, value);
SaveCommand.RaiseCanExecuteChanged();
}
}
public MyCommand CancelCommand { get; private set; }
public MyCommand SaveCommand { get; private set; }
public event Action Done = delegate { };
private void OnCancel()
{
Done();
}
private void OnSave()
{
Done();
}
private bool CanSave()
{
if (HasEmptyFields())
return false;
return true;
}
private bool HasEmptyFields()
{
return string.IsNullOrEmpty(EditableCustomer.FirstName) || string.IsNullOrEmpty(EditableCustomer.LastName)
|| string.IsNullOrEmpty(EditableCustomer.Phone) || string.IsNullOrEmpty(EditableCustomer.Email);
}
}
All i need to do is to be able to trigger the setter for my EditableCustomer property, but I've been able to do that with it.
what am i missing here??
I see my code and I think that it should be raise everytime each field has text until it becomes true once all my text boxes have text on them.
but nothing happens.
just to understand this is my BindableBase is a class where I apply my INotifyPropertyChanged.
public class BindableBase : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged = delegate { };
protected virtual void OnPropertyChanged(string propertyName)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
protected virtual void SetProperty<T>(ref T member, T val, [CallerMemberName]string propertyName = null)
{
if (object.Equals(member, val))
return;
member = val;
OnPropertyChanged(propertyName);
}
}
I hope someone can enlight me, meanwhile i'll try to keep digging on this issues.
It looks like SaveCommand.RaiseCanExecuteChanged(); is only called when you set the EditableCustomer, but when you modify the values inside that object (ie name, email, etc), nothing is notifying the UI that SaveCommand can execute.
If you're going to break up your view models like that, where you have an encapsulated class that manages the input, then it will need to notify the parent view model of changes. Your AddEditCustomerViewModel does not know when the properties have changed and cannot RaiseCanExecuteChanged() accordingly.
Update
In your case, I would recommend having the view-model route all properties that can be modified by the UI form. For example:
public class AddEditCustomerViewModel : BindableBase
{
public string FirstName
{
get { return _editableCustomer.FirstName; }
set
{
_editableCustomer.FirstName = value;
OnPropertyChanged(nameof(FirstName));
if (!HasEmptyFields())
{
SaveCommand.RaiseCanExecuteChanged();
}
}
}
}
and your XAML should bind directly to the view-model, not the model:
<TextBox Text="{Binding FirstName, Mode=TwoWay}" />
<Page.Resources>
<ResourceDictionary>
<BooleanToVisibilityConverter x:Key="booleanToVisibilityConverter" x:Name="testTest" />
</ResourceDictionary>
</Page.Resources>
itemscontrol:
<Grid Grid.Row="1" Grid.ColumnSpan="2" Name="testName">
<ScrollViewer VerticalScrollBarVisibility="Hidden" PanningMode="Both">
<ItemsControl ItemsSource="{Binding Path=NextMeetingList}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<StackPanel Grid.Column="0" Grid.Row="0">
<Border x:Name = "myVariable" Grid.Column="0" Grid.Row="0" Margin="10" Height="30" Background="#A2C2E7" CornerRadius="5" BorderBrush="#A2C2E7">
<Grid Margin="8,0,8,0" Background="#A2C2E7">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="1*"></ColumnDefinition>
<ColumnDefinition Width="1*"></ColumnDefinition>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="30"/>
</Grid.RowDefinitions>
<TextBlock Grid.Row="0" Grid.Column="0" Foreground="White" FontWeight="Bold" FontSize="15" Margin="0,4,0,0" HorizontalAlignment="Left">month</TextBlock>
<TextBlock Grid.Row="0" Grid.Column="1" Foreground="White" FontWeight="Bold" FontSize="15" Margin="0,4,0,0" HorizontalAlignment="Right">1 Meeting</TextBlock>
</Grid>
</Border>
<Border Grid.Column="0" Grid.Row="0" Margin="10" Height="60" Background="GhostWhite" CornerRadius="3" BorderBrush="{Binding BorderColor}" BorderThickness="0,8,0,0">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="118"></ColumnDefinition>
<ColumnDefinition Width="*"></ColumnDefinition>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="60"/>
</Grid.RowDefinitions>
<TextBlock Grid.Row="0" Grid.Column="0" HorizontalAlignment="Left" FontSize="40" Margin="10,5,0,0" Style="{DynamicResource Lato-Semibold}" Text="{Binding endDate.Day}"/>
<TextBlock Grid.Row="0" Grid.Column="0" HorizontalAlignment="Left" FontSize="12" Margin="77,13,0,0" Height="Auto" Style="{DynamicResource Lato-Semibold}" Text="{Binding DayString}"/>
<TextBlock Grid.Row="0" Grid.Column="0" HorizontalAlignment="Left" FontSize="14" Margin="70,26,0,0" Height="Auto" Style="{DynamicResource Lato-Semibold}" Text="{Binding endDate.Hour}"/>
<TextBlock Grid.Row="0" Grid.Column="0" HorizontalAlignment="Left" FontSize="14" Margin="86,26,0,0" Height="Auto" Style="{DynamicResource Lato-Semibold}" Text=":"/>
<TextBlock Grid.Row="0" Grid.Column="0" HorizontalAlignment="Left" FontSize="14" Margin="90,26,0,0" Height="Auto" Style="{DynamicResource Lato-Semibold}" Text="{Binding MinuteString}"/>
<Border Grid.Row="0" Grid.Column="0" Width="1" BorderBrush="#BABABA" Height="40" Margin="115,-6,0,0" BorderThickness="1" HorizontalAlignment="Left"></Border>
<TextBlock Grid.Row="0" Grid.Column="1" HorizontalAlignment="Left" Text="{Binding subject}" FontWeight="Bold" FontSize="17" Margin="10,10,0,0"/>
<TextBlock Grid.Row="0" Grid.Column="1" Width="Auto" TextWrapping="Wrap" HorizontalAlignment="Left" Text="{Binding descr}" FontSize="10" Margin="20,27,150,0"/>
<TextBlock Grid.Row="0" Grid.Column="1" HorizontalAlignment="Right" Text="{Binding companyName}" FontSize="10" Margin="0,10,30,0"/>
<TextBlock Grid.Row="0" Grid.Column="1" HorizontalAlignment="Right" Text="sala del consiglio" FontSize="10" Margin="0,27,30,0"/>
<TextBlock Grid.Row="0" Grid.Column="1" HorizontalAlignment="Right" Text=">" FontSize="15" VerticalAlignment="Center" Margin="0,-5,10,0"/>
</Grid>
</Border>
</StackPanel>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</ScrollViewer>
</Grid>
Hello everyone , I should be able to make a grid Collapsed inside a ItemsControl in WPF .
The problem is that I can not understand how to use the booleanToVisibilityConverter from code behind .
Maybe I'm missing out on a glass of water but I can not connect how to do, if the name TestTest septum can not see it then the code-behind .
from code behind i don't see "myVariable"
To get hold of the converter from code-behind, you'd have to look it up in the Page's Resources dictionary. Do something like this in your Page class:
IValueConverter converter = this.Resources["booleanToVisibilityConverter"] as IValueConverter;
Giving the converter's resource entry a Name is not necessary; here you want to use the Key. Also, converters are normally used with XAML bindings -- if you want one in code, you can just instantiate one:
IValueConverter converter = new BooleanToVisibilityConverter();
Common usage goes something like this:
<Window.Resources>
<ResourceDictionary>
<BooleanToVisibilityConverter x:Key="Converter" />
</ResourceDictionary>
</Window.Resources>
<Grid Visibility="{Binding Display, Converter={StaticResource Converter}}">
...
</Grid>
Code-behind, using the window class itself as the data context:
public partial class MainWindow
{
public bool Display { get; set; };
public MainWindow()
{
InitializeComponent();
DataContext = this; // For the binding
Display = true;
}
}
Okay, one more, this time without data binding or converter:
<Grid x:Name="myGrid">
...
</Grid>
Code-behind:
public partial class MainWindow
{
public MainWindow()
{
InitializeComponent();
myGrid.Visibility = Visibility.Visible;
}
}
The above doesn't explain why the OP couldn't reference "myVariable" from code-behind. That's because it's in a template, which is instantiated (dynamically) once per item in the collection.
It's still possible to get at it from code -- dynamically. For example, this XAML uses a DataTemplate:
<ItemsControl ItemsSource="{Binding Names}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<Grid>
<Grid x:Name="innerGrid" Loaded="OnGridLoaded" DataContext="{Binding Name, Mode=OneWay}">
<TextBox Text="{Binding Path=., Mode=OneWay}" />
</Grid>
</Grid>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
The following code-behind lets us reach into the template and make "innerGrid" disappear selectively:
public class Data
{
public string Name { get; }
public Data(string name)
{
Name = name;
}
}
public partial class MainWindow
{
public Data[] Names { get; } = { new Data("Hello"), new Data("World") };
public MainWindow()
{
InitializeComponent();
DataContext = this;
}
private void OnGridLoaded(object sender, RoutedEventArgs e)
{
Grid outerGrid = sender as Grid;
Grid innerGrid = outerGrid?.FindName("innerGrid") as Grid;
if (innerGrid != null)
{
string name = innerGrid.DataContext as string;
if (name == "Hello")
{
innerGrid.Visibility = Visibility.Collapsed;
}
}
}
}
(To make the string easily accessible I bound the Data object to the "innerGrid" DataContext.)
I have a Pivot view in my WP8 app, and I'm trying to access the data collection from the view's class upon Click event "removePin".
The source of the data collection is another class called Pins.
how can I achieve that?
this is my snippet code for the XAML for that particular part
<phone:PivotItem Header="Pins">
<!-- Content Panel -->
<Grid x:Name="ContentPanel2" HorizontalAlignment="Left" Height="583" Margin="10,10,0,0" Grid.Row="1" VerticalAlignment="Top" Width="460">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="400*"/>
<ColumnDefinition Width="0*"/>
<ColumnDefinition Width="87*"/>
</Grid.ColumnDefinitions>
<ListBox x:Name="lstData2" ItemsSource="{Binding DataCollection2, Source={StaticResource PinsCollection}}"
Grid.ColumnSpan="3" Foreground="#FF1D53D0" Height="583" VerticalAlignment="Bottom">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal" Tap="StackPanel_Tap">
<Image Margin="8" VerticalAlignment="Top" Source="{Binding ImageUri}"
Width="100" Height="100" />
<StackPanel Height="93" Width="259" >
<TextBlock Margin="8" Width="250" TextWrapping="Wrap" VerticalAlignment="Top" HorizontalAlignment="Left" Foreground="#FF1D53D0"
Text="{Binding Pinnedname}" Height="33" RenderTransformOrigin="0.5,0.5" FontFamily="Segoe WP SemiLight" FontSize="24" FontWeight="Bold" />
<TextBlock Width="155" Margin="8,0,8,8" VerticalAlignment="Top"
HorizontalAlignment="Left" Text="{Binding Status}" Foreground="#FF1D53D0" FontFamily="Segoe WP SemiLight" />
</StackPanel>
<toolkit:ContextMenuService.ContextMenu>
<toolkit:ContextMenu>
<toolkit:MenuItem Header="Remove Pin" Click="RemovePin_Click" Tag="{Binding pinId}"/>
</toolkit:ContextMenu>
</toolkit:ContextMenuService.ContextMenu>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
<!-- End of Content Panel -->
</Grid>
Create a custom command class:
public class CustomCommand : ICommand
{
Action _exec;
public CustomCommand(Action exec)
{
_exec = exec;
}
public void Execute(object parameter)
{
if (_exec != null) _exec();
}
public bool CanExecute(object parameter)
{
return true;
}
public event EventHandler CanExecuteChanged;
}
Add it to the view model for elements of pins collection (I supposed it's PinItem)
public CustomCommand RemovePinCommand
{
get { return (CustomCommand)GetValue(RemovePinCommandProperty); }
set { SetValue(RemovePinCommandProperty, value); }
}
public static readonly DependencyProperty RemovePinCommandProperty =
DependencyProperty.Register("RemovePinCommand",
typeof(CustomCommand),
typeof(PinItem),
new UIPropertyMetadata(null));
In the constructor of that class implement your logic for this command:
RemovePinCommand = new CustomCommand(() =>
{
//delete this pin from its parent collection
});
final step is to bind the command to the menu item:
<toolkit:MenuItem Header="Remove Pin" Command="{Binding RemovePinCommand}"/>
I want to enable button when a grid view item is selected so that i will update my GUI in metro apps. The button is also include as a list view item. Below is the code snippet of what i want to do. Please help.
<GridView Name="searchPanelGrid" SelectionMode="Single"
HorizontalAlignment="Left"
ScrollViewer.IsHorizontalScrollChainingEnabled="True"
ScrollViewer.IsVerticalScrollChainingEnabled ="True"
ScrollViewer.HorizontalScrollBarVisibility="Auto"
ScrollViewer.VerticalScrollBarVisibility="Auto"
ScrollViewer.HorizontalScrollMode="Enabled"
ScrollViewer.VerticalScrollMode="Enabled"
ItemsSource="{Binding Source={StaticResource CollectionItems}}" Grid.Row="2">
<GridView.ItemsPanel>
<ItemsPanelTemplate>
<WrapGrid Orientation="Horizontal" />
</ItemsPanelTemplate>
</GridView.ItemsPanel>
<GridView.ItemTemplate>
<DataTemplate>
<Grid Margin="6" Height="175" Width="150" Background="#FFFAFAFA">
<Grid.RowDefinitions>
<RowDefinition Height="85"/>
<RowDefinition Height="50"/>
<RowDefinition Height="30"/>
</Grid.RowDefinitions>
<StackPanel Background="#FF0A56BF" Width="150" Height="85" Grid.Row="0">
<Image Source="{Binding Path=ThumnailUrl}" Stretch="UniformToFill" HorizontalAlignment="Left" VerticalAlignment="Top"/>
</StackPanel>
<TextBlock Text="{Binding Path=VideoName}" TextWrapping="Wrap" Foreground="#FF017DD5" Grid.Row="1" HorizontalAlignment="Left" VerticalAlignment="Top" Height="Auto" FontSize="12"/>
<Button x:Name="downloadButton" Grid.Row="3" Content="Download Video" HorizontalAlignment="Left" VerticalAlignment="Bottom" Style="{StaticResource DownloadButtonStyle}" Click="downloadButton_Click" IsEnabled="{Binding}" />
</Grid>
</DataTemplate>
</GridView.ItemTemplate>
</GridView>
Unable to bind button property IsEnabled. Any suggestion how i do this ??
I have solve this by declaring a property in my Class by which collectionitems is bind and bind that property to button isenabled property and then on SelectionChangeEvent i get selected item of grid view and set button isenabled property value to true. Its working.
Xaml file SearchPanel.xaml
<GridView Name="searchPanelGrid" SelectionMode="Single"
HorizontalAlignment="Left"
ScrollViewer.IsHorizontalScrollChainingEnabled="True"
ScrollViewer.IsVerticalScrollChainingEnabled ="True"
ScrollViewer.HorizontalScrollBarVisibility="Auto"
ScrollViewer.VerticalScrollBarVisibility="Auto"
ScrollViewer.HorizontalScrollMode="Enabled"
ScrollViewer.VerticalScrollMode="Enabled"
ItemsSource="{Binding Source={StaticResource CollectionItems}}" Grid.Row="2" SelectionChanged="searchPanelGrid_SelectionChanged">
<GridView.ItemsPanel>
<ItemsPanelTemplate>
<WrapGrid Orientation="Horizontal" />
</ItemsPanelTemplate>
</GridView.ItemsPanel>
<GridView.ItemTemplate>
<DataTemplate>
<Grid Margin="6" Height="175" Width="150" Background="#FFFAFAFA">
<Grid.RowDefinitions>
<RowDefinition Height="85"/>
<RowDefinition Height="50"/>
<RowDefinition Height="30"/>
</Grid.RowDefinitions>
<StackPanel Background="#FF0A56BF" Width="150" Height="85" Grid.Row="0">
<Image Source="{Binding Path=ThumnailUrl}" Stretch="UniformToFill" HorizontalAlignment="Left" VerticalAlignment="Top"/>
</StackPanel>
<TextBlock Text="{Binding Path=VideoName}" TextWrapping="Wrap" Foreground="#FF017DD5" Grid.Row="1" HorizontalAlignment="Left" VerticalAlignment="Top" Height="Auto" FontSize="12"/>
<Button x:Name="downloadButton" Grid.Row="3" Content="Download Video" HorizontalAlignment="Left" VerticalAlignment="Bottom" Style="{StaticResource DownloadButtonStyle}" Click="downloadButton_Click" IsEnabled="{Binding IsSelected}" />
</Grid>
</DataTemplate>
</GridView.ItemTemplate>
</GridView>
Class that is bind to ItemsSource propertry of GridView
public class VideoInfo : INotifyPropertyChanged
{
private bool isSelected;
public bool IsSelected
{
get { return isSelected; }
set
{
isSelected = value;
NotifyPropertyChanged("IsSelected");
}
}
private string thumnailUrl;
public string ThumnailUrl
{
get { return thumnailUrl; }
set
{
thumnailUrl = value;
NotifyPropertyChanged("ThumnailUrl");
}
}
private string videoName;
public string VideoName
{
get { return videoName; }
set
{
videoName = value;
NotifyPropertyChanged("VideoName");
}
}
public event PropertyChangedEventHandler PropertyChanged;
private void NotifyPropertyChanged(string info)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(info));
}
}
}
.cs file SearchPanel.xaml.cs on SelectionChangeEvent of GridView
private void searchPanelGrid_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
MovieInfo info = (e.AddedItems[0]) as MovieInfo;
info.IsSelected = true;
}