我遇到来自ItemsControl的按钮的命令绑定问题。由于某种原因，命令没有被触发。我的按钮通过绑定到ItemsControl的可观察集合显示。
我在SO中遵循了一些说明，例如绑定到relativesource和元素名称，但仍无法正常工作。
型号：
namespace InteractiveExam.Model
{
class Resource
{
long _resourceID;
public long ResourceID
{
get { return _resourceID; }
set { _resourceID = value; }
}
string _resourceTitle;
public string ResourceTitle
{
get { return _resourceTitle; }
set { _resourceTitle = value; }
}
string _filename;
public string Filename
{
get { return _filename; }
set { _filename = value; }
}
string _resourceModuleID;
public string ResourceModuleID
{
get { return _resourceModuleID; }
set { _resourceModuleID = value; }
}
string _resourceType;
public string ResourceType
{
get { return _resourceType; }
set { _resourceType = value; }
}
}
}
ViewModel 1：
class ResourceViewModel : INotifyPropertyChanged
{
Resource resource;
public Resource Resource
{
get
{
return resource;
}
set
{
resource = value;
}
}
public long ResourceID
{
get
{
return Resource.ResourceID;
}
set
{
if (Resource.ResourceID != value)
{
Resource.ResourceID = value;
RaisePropertyChanged("ResourceID");
}
}
}
public string ResourceTitle
{
get
{
return Resource.ResourceTitle;
}
set
{
if (Resource.ResourceTitle != value)
{
Resource.ResourceTitle = value;
RaisePropertyChanged("ResourceTitle");
}
}
}
public string Filename
{
get
{
return Resource.Filename;
}
set
{
if (Resource.Filename != value)
{
Resource.Filename = value;
RaisePropertyChanged("Filename");
}
}
}
public string ResourceModuleID
{
get
{
return Resource.ResourceModuleID;
}
set
{
if (Resource.ResourceModuleID != value)
{
Resource.ResourceModuleID = value;
RaisePropertyChanged("ResourceModuleID");
}
}
}
public string ResourceType
{
get
{
return Resource.ResourceType;
}
set
{
if (Resource.ResourceType != value)
{
Resource.ResourceType = value;
RaisePropertyChanged("ResourceType");
}
}
}
#region PropertyChanged
public event PropertyChangedEventHandler PropertyChanged;
private void RaisePropertyChanged(string propertyName)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(propertyName));
}
}
#endregion
ViewModel 2（这是我的视图Datacontext）：
class MultiMediaViewerViewModel : INotifyPropertyChanged
{
string connectionStringLocal = ConfigurationManager.ConnectionStrings["LocalDB"].ConnectionString;
public MultiMediaViewerViewModel()
{
LoadModules();
LoadResources();
}
#region Module
private Module module = new Module();
static ObservableCollection<ModuleViewModel> _modules = new ObservableCollection<ModuleViewModel>();
public static ObservableCollection<ModuleViewModel> Modules
{
get
{
return _modules;
}
set
{
_modules = value;
}
}
private void LoadModules()
{
SqlConnection thisConnection = new SqlConnection(connectionStringLocal);
thisConnection.Open();
string Get_Data = "SELECT * FROM module ORDER BY moduleName";
SqlCommand cmd = thisConnection.CreateCommand();
cmd.CommandText = Get_Data;
SqlDataAdapter sda = new SqlDataAdapter(cmd);
DataTable dt = new DataTable("module");
sda.Fill(dt);
foreach (DataRow row in dt.Rows)
{
module.ModuleID = row["moduleID"].ToString();
module.ModuleName = row["moduleName"].ToString();
module.ModulePrerequisiteID = row["prerequisiteID"].ToString();
module.ModuleCourseID = row["courseID"].ToString();
_modules.Add(new ModuleViewModel {Module = new Module{ ModuleID = module.ModuleID, ModuleName = module.ModuleName, ModulePrerequisiteID = module.ModulePrerequisiteID, ModuleCourseID = module.ModuleCourseID } });
}
//close and dispose
thisConnection.Close();
thisConnection.Dispose();
cmd.Dispose();
dt.Dispose();
}
#endregion
#region Resources
private Resource resource = new Resource();
static ObservableCollection<ResourceViewModel> _resources = new ObservableCollection<ResourceViewModel>();
public static ObservableCollection<ResourceViewModel> Resources
{
get
{
return _resources;
}
set
{
_resources = value;
}
}
private void LoadResources()
{
SqlConnection thisConnection = new SqlConnection(connectionStringLocal);
thisConnection.Open();
string Get_Data = "SELECT * FROM resource ORDER BY resourceTitle";
SqlCommand cmd = thisConnection.CreateCommand();
cmd.CommandText = Get_Data;
SqlDataAdapter sda = new SqlDataAdapter(cmd);
DataTable dt = new DataTable("resource");
sda.Fill(dt);
foreach (DataRow row in dt.Rows)
{
resource.ResourceID = Convert.ToInt64(row["id"]);
resource.ResourceTitle = row["resourceTitle"].ToString();
resource.Filename = row["filename"].ToString();
resource.ResourceModuleID = row["resourceModuleID"].ToString();
resource.ResourceType = row["resourceType"].ToString();
_resources.Add(new ResourceViewModel { Resource = new Resource { ResourceID = resource.ResourceID, ResourceTitle = resource.ResourceTitle, Filename = resource.Filename, ResourceModuleID = resource.ResourceModuleID, ResourceType = resource.ResourceType } });
}
//close and dispose
thisConnection.Close();
thisConnection.Dispose();
cmd.Dispose();
dt.Dispose();
}
#endregion
#region MediaPlayer
string resourceFolder = ConfigurationManager.AppSettings["resourceFolder"].ToString();
private MediaPlayer mediaPlayer = new MediaPlayer();
static ObservableCollection<MediaPlayerViewModel> _mediaPlayers = new ObservableCollection<MediaPlayerViewModel>();
public static ObservableCollection<MediaPlayerViewModel> MediaPlayers
{
get
{
return _mediaPlayers;
}
set
{
_mediaPlayers = value;
}
}
private void LoadMediaElementDefaults()
{
//mediaPlayer.TimelineSlider.Maximum = mediaPlayer.MediaElementPlayer.NaturalDuration.TimeSpan.TotalMilliseconds;
string mediaFullpath = resourceFolder + "Dubai2021.mp4";
mediaPlayer.MediaUri = new Uri(mediaFullpath, UriKind.Absolute);
//_mediaPlayers.Add(new MediaPlayerViewModel { MediaPlayer = new MediaPlayer { MediaUri = mediaPlayer.MediaUri } });
}
Uri _mediaUri;
public Uri MediaUri
{
get
{
return _mediaUri;
}
set
{
if (_mediaUri != value)
{
_mediaUri = value;
RaisePropertyChanged("MediaUri");
}
}
}
public ICommand PlayCommand { get { return new RelayCommand(PlayCommandExecute, CanPlayCommandExecute); } }
void PlayCommandExecute()
{
string mediaFullpath = resourceFolder + "Dubai2021.mp4";
MediaUri = new Uri(mediaFullpath, UriKind.Absolute);
if (this.PlayRequested != null)
{
this.PlayRequested(this, EventArgs.Empty);
}
}
bool CanPlayCommandExecute()
{
return true;
}
public event EventHandler PlayRequested;
}
查看：
<StackPanel DockPanel.Dock="Right" HorizontalAlignment="Right"
Width="250" VerticalAlignment="Stretch">
<ScrollViewer HorizontalScrollBarVisibility="Disabled"
VerticalScrollBarVisibility="Hidden" CanContentScroll="True"
PanningMode="VerticalOnly"
Height="{Binding ElementName=mainGrid,Path=ActualHeight}"
ManipulationBoundaryFeedback="ScrollViewer_ManipulationBoundaryFeedback"
Padding="0,0,0,130">
<DockPanel>
<StackPanel>
<ItemsControl ItemsSource="{Binding Resources}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<Button Template="{StaticResource ctButton}" Margin="0,0,0,5"
Tag="{Binding ResourceID}"
Command="{Binding RelativeSource={RelativeSource FindAncestor,AncestorType=Window},Path=DataContext.PlayCommand}">
<TextBlock
Text="{Binding ResourceTitle}"
TextWrapping="Wrap"
Width="170"
Height="70"
FlowDirection="LeftToRight"/>
</Button>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</StackPanel>
</DockPanel>
</ScrollViewer>
</StackPanel>