wpf command custom control binding xaml

Question

Hello there,

i'm building a Videoplayer custom control (Project called WpfCustomControlLibrary1) and want to add a Load Command.

This is what i have added in my class to get this Command:

Public Class VideoPlayer
Inherits Control
...
Public Shared ReadOnly LoadCommad As RoutedUICommand
....

Shared Sub New()
    'This OverrideMetadata call tells the system that this element wants to provide a style that is different than its base class.
    'This style is defined in Themes\Generic.xaml
    DefaultStyleKeyProperty.OverrideMetadata(GetType(VideoPlayer), New FrameworkPropertyMetadata(GetType(VideoPlayer)))

    LoadCommad = New RoutedUICommand("Load", "Load Video", GetType(VideoPlayer))
    CommandManager.RegisterClassCommandBinding(GetType(VideoPlayer), New CommandBinding(LoadCommad, AddressOf OnLoadExecuted))
End Sub
...

And this is how i call it from my XAML:

<ResourceDictionary
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:WpfCustomControlLibrary1">
.....
<Button Command="local:VideoPlayer.LoadCommand"
        DockPanel.Dock="Right" Margin="0 5 5 0"
        Width="30" HorizontalAlignment="Left"
        Content="..." />
.....

But when i add this Usercontrol to a new Project like this:

<Window x:Class="Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:bibli="clr-namespace:EigeneControllsBibli;assembly=EigeneControllsBibli"
xmlns:uc="clr-namespace:WpfCustomControlLibrary1;assembly=WpfCustomControlLibrary1"
Title="Window1" Height="442" Width="804">
<Grid>
    <uc:VideoPlayer Source="C:\Users\Public\Videos\Sample Videos\Bear.wmv" Margin="0,106,369,0"></uc:VideoPlayer>
</Grid>

i get an error that he cant convert the string in the Attribute "Command" into an Object of the Type "System.Windows.Input.ICommand

Does somebody see whats going wrong?

Thanks for helping, Nico

Answer 1

you have a spelling-mistake:

LoadCommad = New RoutedUICommand("Load", "Load Video", GetType(VideoPlayer))

should be

LoadCommand = New RoutedUICommand("Load", "Load Video", GetType(VideoPlayer))

I don't know if this produces the error, but perhaps.

Answer 2

I think what you want to do is declare LoadCommand as an instance rather than Shared variable, so:

Public Class VideoPlayer
Inherits Control
...
Private ReadOnly m_LoadCommand As RoutedUICommand
....

Shared Sub New()
    'This OverrideMetadata call tells the system that this element wants to provide a style that is different than its base class.
    'This style is defined in Themes\Generic.xaml
    DefaultStyleKeyProperty.OverrideMetadata(GetType(VideoPlayer), New FrameworkPropertyMetadata(GetType(VideoPlayer)))
End Sub

Sub New()
    m_LoadCommand = New RoutedUICommand("Load", "Load Video", GetType(VideoPlayer))
End Sub

Public Property LoadCommand As ICommand
   Get
      Return m_LoadCommand
   End Get
End Property 
...

Then you bind the Button.Command property in the XAML, so:

<StackPanel>
    <uc:VideoPlayer x:Name="myPlayer" Source="C:\Users\Public\Videos\Sample Videos\Bear.wmv" Margin="0,106,369,0"></uc:VideoPlayer>
    <Button Command="{Binding ElementName=myPlayer, Path=LoadCommand"
        Width="30"
        Content="..." />
</StackPanel>