DataTemplate Problem

Kevin Marois

I have an app that displays 1 to 16 video player controls. The user can select the type of player (ie LeadTools, VLC) and the number of players to show. Once the type and number of players is selected, I load the players into the main window's Players collection. The ActiveX player is hosted in a PlayerHostViewl, and that is added to an ObservableCollection called 'Players' Here's the main window's XAML's resources, showing the data template for the collection:

<Window.Resources>

<DataTemplate DataType="{x:Type vms:PlayerHostViewModel}">
    <vws:PlayerHostView/>
</DataTemplate>

</Window.Resources>

and the MainWindow's player collection:

<ItemsControl ItemsSource="{Binding Players}"
                Margin="2">
            
    <ItemsControl.ItemsPanel>
        <ItemsPanelTemplate>
            <UniformGrid IsItemsHost="True"
                            Margin="2"/>
        </ItemsPanelTemplate>
    </ItemsControl.ItemsPanel>
            
</ItemsControl>

</Border>

The MainWindowViewModel's LoadPlayers method:

private void LoadPlayers()
{
// If a player type and count are selected...
if (SelectedPlayerInfo != null && SelectedPlayerCount > -1)
{
// For each player to add...
for (int i = 0; i < SelectedPlayerCount + 1; i++)
{
// Create the player ActiveX control
var playerAssembly = (IPlayer)Activator.CreateInstance(SelectedPlayerInfo.PlayerType);

        // Create the player host
        var player = new PlayerHostViewModel(playerAssembly, $"Player {i + 1}", LiveStream, DVRStream);
     
        // Add the player host to the Players list
        Players.Add(player);
    }
}

}

Here's the PlayerHost CTORs

public PlayerHostViewModel()
{
}
public PlayerHostViewModel(IPlayer player, string playerName, string liveStream, string dvrStream)
{
Player = player;
PlayerName = playerName;
LiveStream = LiveStream;
DVRStream = dvrStream;
}

The problem is that the PlayerHost paramterized CTOR fires when this line executes, as it should:

var player = new PlayerHostViewMo

Richard Deeming

It sounds like you're creating two instances of the viewmodel. What does the PlayerHostView look like?

"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer