C#•3y ago

.NET WPF APP - Trying to bind a command to a button but not working

57 Replies

ByLifeOP•3y ago

I'm so confused of why is it not working hhh

Klarth•3y ago

So this is an error in the XAML editor/designer. You need to be skeptical of those as they're less reliably true than ones coming from C#.

ByLifeOP•3y ago

Ok ❤️

Patrick•3y ago

post full xaml

ByLifeOP•3y ago

Sure

Klarth•3y ago

Ensure you've tried to build and run the app. If that causes an exception, then it's a real error. If it doesn't actually build, then check the Output window for details.

ByLifeOP•3y ago

<Window x:Class="WpfApp1.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:viewModel="clr-namespace:WpfApp1.MVVM.ViewModel"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfApp1"
        mc:Ignorable="d"
        Title="NasaProject" 
        Height="600" 
        Width="920"
        WindowStyle="None"
        AllowsTransparency="True"
        Background="Transparent"
        >

    <Window.DataContext>
        <viewModel:MainViewModel/>
    </Window.DataContext>
    <Border Background="#272537" CornerRadius="20">
        <Grid>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="200"/>
                <ColumnDefinition/>
            </Grid.ColumnDefinitions>
            <Grid.RowDefinitions>
                <RowDefinition Height="101*"/>
                <RowDefinition Height="499*"/>
            </Grid.RowDefinitions>

            <TextBlock Text="Nasa Project"
                   VerticalAlignment="Top"
                   HorizontalAlignment="Left"
                   Foreground="White"
                   FontSize="22"
                   Margin="20,20,0,0" Height="29" Width="122"
            />

            <StackPanel Grid.Row="1">
                <RadioButton Content="Home"
                             Height="50"
                             Foreground="White"
                             FontSize="14"
                             IsChecked="True"
                             Style="{StaticResource MenuButtonTheme}"
                             Command="{Binding HomeViewCommand}"
                />
                
                <RadioButton Content="API"
                             Height="50"
                             Foreground="White"
                             FontSize="14"
                             Style="{StaticResource MenuButtonTheme}"
                             Command="{Binding AsteroidsViewCommand}"
                />
                
                <RadioButton Content="Home"
                             Height="50"
                             Foreground="White"
                             FontSize="14"
                             Style="{StaticResource MenuButtonTheme}"
                />
            </StackPanel>

            <TextBox Width="250"
                       Height="40"
                       VerticalAlignment="Center"
                       HorizontalAlignment="Left"
                       Margin="5"
                       Grid.Column="1"
                       Style="{StaticResource ModernTextbox}" TextChanged="TextBox_TextChanged" Text="fazaf&#xD;&#xA;"
                       />

            <ContentControl Grid.Row="1" 
                            Grid.Column="1" 
                            Margin="10"
                            Content="{Binding CurrentView}"/>
        </Grid>
    </Border>
</Window>

<Window x:Class="WpfApp1.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:viewModel="clr-namespace:WpfApp1.MVVM.ViewModel"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfApp1"
        mc:Ignorable="d"
        Title="NasaProject" 
        Height="600" 
        Width="920"
        WindowStyle="None"
        AllowsTransparency="True"
        Background="Transparent"
        >

    <Window.DataContext>
        <viewModel:MainViewModel/>
    </Window.DataContext>
    <Border Background="#272537" CornerRadius="20">
        <Grid>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="200"/>
                <ColumnDefinition/>
            </Grid.ColumnDefinitions>
            <Grid.RowDefinitions>
                <RowDefinition Height="101*"/>
                <RowDefinition Height="499*"/>
            </Grid.RowDefinitions>

            <TextBlock Text="Nasa Project"
                   VerticalAlignment="Top"
                   HorizontalAlignment="Left"
                   Foreground="White"
                   FontSize="22"
                   Margin="20,20,0,0" Height="29" Width="122"
            />

            <StackPanel Grid.Row="1">
                <RadioButton Content="Home"
                             Height="50"
                             Foreground="White"
                             FontSize="14"
                             IsChecked="True"
                             Style="{StaticResource MenuButtonTheme}"
                             Command="{Binding HomeViewCommand}"
                />
                
                <RadioButton Content="API"
                             Height="50"
                             Foreground="White"
                             FontSize="14"
                             Style="{StaticResource MenuButtonTheme}"
                             Command="{Binding AsteroidsViewCommand}"
                />
                
                <RadioButton Content="Home"
                             Height="50"
                             Foreground="White"
                             FontSize="14"
                             Style="{StaticResource MenuButtonTheme}"
                />
            </StackPanel>

            <TextBox Width="250"
                       Height="40"
                       VerticalAlignment="Center"
                       HorizontalAlignment="Left"
                       Margin="5"
                       Grid.Column="1"
                       Style="{StaticResource ModernTextbox}" TextChanged="TextBox_TextChanged" Text="fazaf&#xD;&#xA;"
                       />

            <ContentControl Grid.Row="1" 
                            Grid.Column="1" 
                            Margin="10"
                            Content="{Binding CurrentView}"/>
        </Grid>
    </Border>
</Window>

It is building But the buttons won't work

Patrick•3y ago

are you doing anything in codebehind

ByLifeOP•3y ago

Let me screen that for you

Patrick•3y ago

also if you're using MVVM Toolkit I'd just use [RelayCommand] and make a method, to be honest.

ByLifeOP•3y ago

Thats what I did ^^ In my app.xaml : <Application x:Class="WpfApp1.App" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:local="clr-namespace:WpfApp1" xmlns:viewModel="clr-namespace:WpfApp1.MVVM.ViewModel" xmlns:view="clr-namespace:WpfApp1.MVVM.View" StartupUri="MainWindow.xaml"> <Application.Resources> <ResourceDictionary> <ResourceDictionary.MergedDictionaries> <ResourceDictionary Source="./Theme/MenuButtonTheme.xaml" /> <ResourceDictionary Source="./Theme/TextboxTheme.xaml"/> </ResourceDictionary.MergedDictionaries> <DataTemplate DataType="{x:Type viewModel:HomeViewModel}"> <view:HomeView></view:HomeView> </DataTemplate> <DataTemplate DataType="{x:Type viewModel:AsteroidsViewModel}"> <view:AsteroidsView></view:AsteroidsView> </DataTemplate> </ResourceDictionary> </Application.Resources> </Application>

Patrick•3y ago

that's not what you've posted

ByLifeOP•3y ago

I'm loading my models Uh Thats how i load it

Patrick•3y ago

I still need the code behind for the main window

ByLifeOP•3y ago

Ok It is this one:

using WpfApp1.Core;

namespace WpfApp1.MVVM.ViewModel
{
    class MainViewModel : ObservableObject
    {

        public RelayCommand HomeViewCommand { get; set; }
        public RelayCommand AsteroidsViewCommand { get; set; }

        public HomeViewModel HomeVM { get; set; }

        public AsteroidsViewModel AsteroidsVM { get; set; }

        private object _currentView;

        public object CurrentView
        {
            get { return _currentView; }
            set
            {
                _currentView = value;
                OnPropertyChanged();
            }
        }
        public MainViewModel() 
        {
            HomeVM = new HomeViewModel();
            AsteroidsVM = new AsteroidsViewModel();
            CurrentView = HomeVM;

            HomeViewCommand = new RelayCommand((o) =>
            {
                CurrentView = HomeVM;
            });

            AsteroidsViewCommand = new RelayCommand((o) =>
            {
                CurrentView = AsteroidsVM;
            });
        }
    }
}

using WpfApp1.Core;

namespace WpfApp1.MVVM.ViewModel
{
    class MainViewModel : ObservableObject
    {

        public RelayCommand HomeViewCommand { get; set; }
        public RelayCommand AsteroidsViewCommand { get; set; }

        public HomeViewModel HomeVM { get; set; }

        public AsteroidsViewModel AsteroidsVM { get; set; }

        private object _currentView;

        public object CurrentView
        {
            get { return _currentView; }
            set
            {
                _currentView = value;
                OnPropertyChanged();
            }
        }
        public MainViewModel() 
        {
            HomeVM = new HomeViewModel();
            AsteroidsVM = new AsteroidsViewModel();
            CurrentView = HomeVM;

            HomeViewCommand = new RelayCommand((o) =>
            {
                CurrentView = HomeVM;
            });

            AsteroidsViewCommand = new RelayCommand((o) =>
            {
                CurrentView = AsteroidsVM;
            });
        }
    }
}

Patrick•3y ago

no, that's your view model. I'm asking for the code behind of the main window. MainWindow.xaml.cs

ByLifeOP•3y ago

Sorry

<Window x:Class="WpfApp1.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:viewModel="clr-namespace:WpfApp1.MVVM.ViewModel"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfApp1"
        mc:Ignorable="d"
        Title="NasaProject" 
        Height="600" 
        Width="920"
        WindowStyle="None"
        AllowsTransparency="True"
        Background="Transparent"
        >

    <Window.DataContext>
        <viewModel:MainViewModel/>
    </Window.DataContext>
    <Border Background="#272537" CornerRadius="20">
        <Grid>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="200"/>
                <ColumnDefinition/>
            </Grid.ColumnDefinitions>
            <Grid.RowDefinitions>
                <RowDefinition Height="101*"/>
                <RowDefinition Height="499*"/>
            </Grid.RowDefinitions>

            <TextBlock Text="Nasa Project"
                   VerticalAlignment="Top"
                   HorizontalAlignment="Left"
                   Foreground="White"
                   FontSize="22"
                   Margin="20,20,0,0" Height="29" Width="122"
            />

            <StackPanel Grid.Row="1">
                <RadioButton Content="Home"
                             Height="50"
                             Foreground="White"
                             FontSize="14"
                             IsChecked="True"
                             Style="{StaticResource MenuButtonTheme}"
                             Command="{Binding HomeViewCommand}"
                />
                
                <RadioButton Content="API"
                             Height="50"
                             Foreground="White"
                             FontSize="14"
                             Style="{StaticResource MenuButtonTheme}"
                             Command="{Binding AsteroidsViewCommand}"
                />
                
                <RadioButton Content="Home"
                             Height="50"
                             Foreground="White"
                             FontSize="14"
                             Style="{StaticResource MenuButtonTheme}"
                />
            </StackPanel>

            <TextBox Width="250"
                       Height="40"
                       VerticalAlignment="Center"
                       HorizontalAlignment="Left"
                       Margin="5"
                       Grid.Column="1"
                       Style="{StaticResource ModernTextbox}" TextChanged="TextBox_TextChanged" Text="fazaf&#xD;&#xA;"
                       />

            <ContentControl Grid.Row="1" 
                            Grid.Column="1" 
                            Margin="10"
                            Content="{Binding CurrentView}"/>
        </Grid>
    </Border>
</Window>

<Window x:Class="WpfApp1.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:viewModel="clr-namespace:WpfApp1.MVVM.ViewModel"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfApp1"
        mc:Ignorable="d"
        Title="NasaProject" 
        Height="600" 
        Width="920"
        WindowStyle="None"
        AllowsTransparency="True"
        Background="Transparent"
        >

    <Window.DataContext>
        <viewModel:MainViewModel/>
    </Window.DataContext>
    <Border Background="#272537" CornerRadius="20">
        <Grid>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="200"/>
                <ColumnDefinition/>
            </Grid.ColumnDefinitions>
            <Grid.RowDefinitions>
                <RowDefinition Height="101*"/>
                <RowDefinition Height="499*"/>
            </Grid.RowDefinitions>

            <TextBlock Text="Nasa Project"
                   VerticalAlignment="Top"
                   HorizontalAlignment="Left"
                   Foreground="White"
                   FontSize="22"
                   Margin="20,20,0,0" Height="29" Width="122"
            />

            <StackPanel Grid.Row="1">
                <RadioButton Content="Home"
                             Height="50"
                             Foreground="White"
                             FontSize="14"
                             IsChecked="True"
                             Style="{StaticResource MenuButtonTheme}"
                             Command="{Binding HomeViewCommand}"
                />
                
                <RadioButton Content="API"
                             Height="50"
                             Foreground="White"
                             FontSize="14"
                             Style="{StaticResource MenuButtonTheme}"
                             Command="{Binding AsteroidsViewCommand}"
                />
                
                <RadioButton Content="Home"
                             Height="50"
                             Foreground="White"
                             FontSize="14"
                             Style="{StaticResource MenuButtonTheme}"
                />
            </StackPanel>

            <TextBox Width="250"
                       Height="40"
                       VerticalAlignment="Center"
                       HorizontalAlignment="Left"
                       Margin="5"
                       Grid.Column="1"
                       Style="{StaticResource ModernTextbox}" TextChanged="TextBox_TextChanged" Text="fazaf&#xD;&#xA;"
                       />

            <ContentControl Grid.Row="1" 
                            Grid.Column="1" 
                            Margin="10"
                            Content="{Binding CurrentView}"/>
        </Grid>
    </Border>
</Window>

Patrick•3y ago

ok, you either deleted the cs file or you're not reading my message properly MainWindow.xaml.cs not MainWindow.xaml

ByLifeOP•3y ago

using System.Windows; namespace WpfApp1 { /// <summary> /// Interaction logic for MainWindow.xaml /// </summary> public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); } private void TextBox_TextChanged(object sender, System.Windows.Controls.TextChangedEventArgs e) { } } }

Patrick•3y ago

thanks

ByLifeOP•3y ago

It didnt show up in my file explorer sorry

Patrick•3y ago

so.... what's not working exactly? seems like it should be working.

ByLifeOP•3y ago

Sure, the command binding is not working But it is building successfully

Klarth•3y ago

Without changing too much, I would write your MainViewModel like the following (this won't fix your problem though)

public partial class MainViewModel : ObservableObject
{
    public HomeViewModel HomeVM { get; }
    public AsteroidsViewModel AsteroidsVM { get; }

    [ObservableObject] private ObservableObject _currentView;

    public MainViewModel() 
    {
        HomeVM = new HomeViewModel();
        AsteroidsVM = new AsteroidsViewModel();
        CurrentView = HomeVM;
    }
    
    [RelayCommand]
    public void HomeView()
    {
        CurrentView = HomeVM;
    }
    
    [RelayCommand]
    public void AsteroidView()
    {
        CurrentView = AsteroidsVM;
    }
}

public partial class MainViewModel : ObservableObject
{
    public HomeViewModel HomeVM { get; }
    public AsteroidsViewModel AsteroidsVM { get; }

    [ObservableObject] private ObservableObject _currentView;

    public MainViewModel() 
    {
        HomeVM = new HomeViewModel();
        AsteroidsVM = new AsteroidsViewModel();
        CurrentView = HomeVM;
    }
    
    [RelayCommand]
    public void HomeView()
    {
        CurrentView = HomeVM;
    }
    
    [RelayCommand]
    public void AsteroidView()
    {
        CurrentView = AsteroidsVM;
    }
}

Patrick•3y ago

define "not working", are you getting an error?

ByLifeOP•3y ago

It is showing me this error "Object reference not set to an instance of objet "

ByLifeOP•3y ago

https://cdn.discordapp.com/attachments/1071875437774520321/1071875933297987624/image.png

ByLifeOP•3y ago

Thanks, I will use it ^^

Klarth•3y ago

What does your app do at runtime? Is the button disabled? Is it enabled and does nothing when you click it?

Patrick•3y ago

ok, that's the designer, but does it actually run and execute the command?

ByLifeOP•3y ago

No it doesn't

Klarth•3y ago

Ensure you've set a breakpoint in the method/command when testing.

ByLifeOP•3y ago

Oops sorry I didn't tell you It doesn't even build sorry

ByLifeOP•3y ago

ByLifeOP•3y ago

I'm getting this error

Patrick•3y ago

I would rewrite it the relay commands as per Klarth's suggestion earlier

Klarth•3y ago

Is this a custom RelayCommand when you're already using Mvvm Toolkit? catsweat

Patrick•3y ago

it will fix your problem, because the way you initialised the relay command makes it expect a command parameter

ByLifeOP•3y ago

Ok I'll try ^^

Patrick•3y ago

(also it's just convenient to make MVVM toolkit do it)

ByLifeOP•3y ago

Patrick•3y ago

wait... you're.... not using MVVM Toolkit?

ByLifeOP•3y ago

I am

Patrick•3y ago

Klarth•3y ago

Why do you have ObservableObject and RelayCommand defined? Use the Mvvm Toolkit's versions.

Patrick•3y ago

ok i think there's confusion here MVVM Toolkit is a Microsoft supported MVVM Framework

ByLifeOP•3y ago

I mean no I don't but I created my own ... 😂

Klarth•3y ago

Patrick•3y ago

Yes, you're doing MVVM, but MVVM Toolkit is a separate library with all of this stuff built in ... and also when

ByLifeOP•3y ago

Ok 😂 I mean I'm beginning in C#

Patrick•3y ago

https://www.nuget.org/packages/CommunityToolkit.Mvvm/

CommunityToolkit.Mvvm 8.1.0

This package includes a .NET MVVM library with helpers such as: - ObservableObject: a base class for objects implementing the INotifyPropertyChanged interface. - ObservableRecipient: a base class for observable objects with support for the IMessenger service. - ObservableValidator: a base class for objects implementing the INot...

Patrick•3y ago

install this and delete your own

ByLifeOP•3y ago

Ok and how do I add the library globaly in the project ?

Klarth•3y ago

FYI, this only applies if you're using the Mvvm Toolkit library.

ByLifeOP•3y ago

Just import it in the mainwindow ?

Patrick•3y ago

walk before running install via nuget into the WPF project.

ByLifeOP•3y ago

Ok then thanks, I will inform you if it is actually good ^^ ! ❤️ Thanks a lot Umm yes using the library is much simpler Love y'all Thanks @Klarth ❤️ And you too @superpat64

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.NET WPF APP - Trying to bind a command to a button but not working

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