I have MainWindowViewModel and AccountViewModel. When I click 'Login' on my MainView:
- data about AvaliableExchages is fetched from database.
- Property CurrentViewModel is set to AccountViewModel.
- AvaliableExchanges property now has 2 strings ("Binance" and "Bitrue"). I can see it in debugger.
The problem is that I can't see them in the View. Combobox that binds its ItemsSource property to AvaliableExchanges Property doesn't show items.
MainViewModel:
internal class MainWindowViewModel : BaseViewModel
{
private List<AppUser> _appUsers = new List<AppUser>();
public List<AppUser> AppUsers
{
get => _appUsers;
set => Set(ref _appUsers, value);
}
public BaseViewModel _currentViewModel;
public BaseViewModel CurrentViewModel
{
get => _currentViewModel;
set => Set(ref _currentViewModel, value);
}
public ICommand LoginCommand { get; }
public bool CanLoginCommandExecute(object p) => true;
public void OnLoginCommandExecuted(object p)
{
if (!string.IsNullOrEmpty(Username) && !string.IsNullOrEmpty(Password))
{
AppUsers = AppUser.GetAppUserByLoginAndPawwsord(Username, Password);
if (AppUsers.Count > 0)
{
List<string> avaliableExchanges = new List<string>();
foreach(var user in AppUsers)
{
avaliableExchanges.Add(user.Exchange);
}
CurrentViewModel = new AccountViewModel(avaliableExchanges);
LoginViewVisibility = Visibility.Collapsed;
MainMenuVisibility = Visibility.Visible;
}
}
}
public MainWindowViewModel()
{
LoginCommand = new RelayCommand(OnLoginCommandExecuted, CanLoginCommandExecute);
}
}
AccountViewModel:
internal class AccountViewModel : BaseViewModel
{
private ObservableCollection<string> _avaliableExchanges;
public ObservableCollection<string> AvaliableExchanges
{
get => _avaliableExchanges;
set => Set(ref _avaliableExchanges, value);
}
public AccountViewModel()
{
}
public AccountViewModel(List<string> avaliableExchanges)
{
AvaliableExchanges = new ObservableCollection<string>(avaliableExchanges);
}
}
MainWindow:
<Window x:Class="ShababTrade.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:ShababTrade"
xmlns:vm="clr-namespace:ShababTrade.ViewModels"
xmlns:views="clr-namespace:ShababTrade.Views"
xmlns:materialDesign="http://materialdesigninxaml.net/winfx/xaml/themes"
mc:Ignorable="d"
Title="Shabab Trade" Height="450" Width="800"
WindowState="Maximized" Background="#FF111111">
<Window.DataContext>
<vm:MainWindowViewModel/>
</Window.DataContext>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Border Grid.Row="0" Grid.Column="0" BorderThickness="0.5" BorderBrush="DarkGray" Margin="5" CornerRadius="5" Visibility="{Binding MainMenuVisibility}">
<StackPanel Orientation="Horizontal" Margin="5">
<Button Style="{StaticResource MainTabStyle}" Background="{Binding AccountTabBackground}" Command="{Binding SelectMainMenuTabCommand}" CommandParameter="Account" Content="Account" />
<Button Style="{StaticResource MainTabStyle}" Background="{Binding TradeHistoryTabBackground}" Command="{Binding SelectMainMenuTabCommand}" CommandParameter="History" Content="Trade History" />
<Button Style="{StaticResource MainTabStyle}" Background="{Binding SpotTabBackground}" Command="{Binding SelectMainMenuTabCommand}" CommandParameter="Spot" Content="Spot" />
<Button Style="{StaticResource MainTabStyle}" Background="{Binding AutoTradingTabBackground}" Command="{Binding SelectMainMenuTabCommand}" CommandParameter="Auto" Content="Auto Trading" Cursor="Hand" />
<Button Style="{StaticResource MainTabStyle}" Background="{Binding FuturesTabBackground}" Command="{Binding SelectMainMenuTabCommand}" CommandParameter="Futures" Content="Futures" Cursor="Hand" />
</StackPanel>
</Border>
<Border Grid.Row="1" Grid.Column="0" BorderThickness="3" CornerRadius="5" Width="350" Height="430"
BorderBrush="{StaticResource PrimaryColorBrush}"
Background="{StaticResource WhiteColorBrush}" Visibility="{Binding LoginViewVisibility}">
<StackPanel>
<TextBlock Margin="0 30 0 0" FontSize="36" TextAlignment="Center" Text="Login"/>
<TextBox Margin="10 50 10 0" FontSize="20" materialDesign:HintAssist.Hint="Username"
Text="{Binding Username}" Cursor="Arrow"/>
<TextBox Margin="10 40 10 0" FontSize="20" materialDesign:HintAssist.Hint="Password"
Text="{Binding Password}" Cursor="Arrow"/>
<Button Margin="10 50 10 0" FontSize="20" Content="Login" Height="40"
Background="{StaticResource SecondaryColorBrush}"
Style="{StaticResource LoginButtonStyle}"
Command="{Binding LoginCommand}" Cursor="Hand"/>
<TextBlock Margin="0 20 0 0" FontSize="16" TextAlignment="Center" >
<Run Text="Not a member?"/>
<Hyperlink Foreground="{StaticResource HyperlinkColorBrush}">Sign in</Hyperlink>
</TextBlock>
</StackPanel>
</Border>
<ContentControl Grid.Row="1" Grid.Column="0" Content="{Binding CurrentViewModel}" Visibility="{Binding MainMenuVisibility}">
</ContentControl>
</Grid>
</Window>
AccountView:
<UserControl x:Class="ShababTrade.Views.AccountView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:local="clr-namespace:ShababTrade.Views"
xmlns:materialDesign="http://materialdesigninxaml.net/winfx/xaml/themes"
xmlns:views="clr-namespace:ShababTrade.ViewModels"
mc:Ignorable="d"
d:DesignHeight="450" d:DesignWidth="800">
<UserControl.DataContext>
<views:AccountViewModel/>
</UserControl.DataContext>
<UserControl.Resources>
<Style TargetType="TextBlock">
<Setter Property="Foreground" Value="White"/>
</Style>
</UserControl.Resources>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<Border Grid.Row="0" Grid.Column="0" BorderThickness="0.5" BorderBrush="DarkGray" Margin="5" CornerRadius="5">
<StackPanel>
<StackPanel Orientation="Horizontal" Margin="1 10 0 0">
<TextBlock Text="Exchange:" Foreground="#D81D3C" FontSize="16" Margin="8 0 0 0"/>
<ComboBox Width="100" Height="25" Margin="5 0 0 0" HorizontalContentAlignment="Left" Padding="5 2 5 0"
Background="#2D2D2D" Foreground="White" materialDesign:ColorZoneAssist.Mode="PrimaryDark"
ItemsSource="{Binding AvaliableExchanges, Mode=TwoWay}">
</ComboBox>
</StackPanel>
<ListView Grid.Row="1" Grid.Column="0" ItemsSource="{Binding Balances}" Foreground="White" >
<ListView.Resources>
<Style TargetType="{x:Type GridViewColumnHeader}" BasedOn="{StaticResource MaterialDesignFlatButton}">
<Setter Property="HorizontalContentAlignment" Value="Left" />
</Style>
</ListView.Resources>
<ListView.ItemContainerStyle>
<Style TargetType="ListViewItem" BasedOn="{StaticResource MaterialDesignGridViewItem}">
<Setter Property="Focusable" Value="false"/>
</Style>
</ListView.ItemContainerStyle>
<ListView.View>
<GridView>
<GridView.ColumnHeaderContainerStyle>
<Style BasedOn="{StaticResource {x:Type GridViewColumnHeader}}" TargetType="{x:Type GridViewColumnHeader}">
<Setter Property="IsHitTestVisible" Value="False"/>
</Style>
</GridView.ColumnHeaderContainerStyle>
<GridView.ColumnHeaderTemplate>
<DataTemplate>
<TextBlock Foreground="White" Text="{Binding}"/>
</DataTemplate>
</GridView.ColumnHeaderTemplate>
<GridViewColumn Header="Asset" DisplayMemberBinding="{Binding Asset}" Width="100"/>
<GridViewColumn Header="Free" DisplayMemberBinding="{Binding Free, StringFormat=N2}" Width="100"/>
<GridViewColumn Header="Locked" DisplayMemberBinding="{Binding Locked, StringFormat=N2}" Width="100"/>
<GridViewColumn Header="Total" DisplayMemberBinding="{Binding Total, StringFormat=N2}" Width="100"/>
<GridViewColumn Header="RubValue" DisplayMemberBinding="{Binding RubValue, StringFormat=N2}" Width="100"/>
</GridView>
</ListView.View>
</ListView>
</StackPanel>
</Border>
</Grid>
</UserControl>
CodePudding user response：
A UserControl must not explicitly set its own DataContext.
Remove
<UserControl.DataContext>
<views:AccountViewModel/>
</UserControl.DataContext>
from the AccountView XAML, because it sets a different AccountViewModel instance than the one the control is expected to operate with.
Also note that it is poinless to set Mode=TwoWay on an ItemsSource Binding.