I have IVector collection property which is bound with xaml element.
using PlatformStringVector = Windows::Foundation::Collections::IVector<Platform::String^>^;
The collection member :
PlatformStringVector m_dataCollection = ref new Platform::Collections::Vector<Platform::String^>();
The Property :
property PlatformStringVector DataCollection
{
PlatformStringVector get() { return m_dataCollection; }
void set(PlatformStringVector value) { SetProperty(m_dataCollection, value, "DataCollection");}
}
I am trying to clean the collection from background thread. If i am clearing the bound property i am getting error from xaml is null.
DataCollection->Clear();
But if the clean up is done by
m_dataCollection->Clear().
Everything works fine.
What is the difference between Property Clear and data driven clear?
/// <summary>Initializes the session asynchronous.</summary>
void App::InitSessionAsync()
{
concurrency::create_task([this]
{
WaitForDevice();
}).then([this](concurrency::task<void> task)
{
try
{
task.get();
}
catch (const Polytec::IO::CommunicationException & ex)
{
..
}
AppData::ViewModel->DataCollection->Clear(); // This clear does not work.
//AppData::ViewModel->ClearCollection(); // It actually clears the data collection member. And this works
auto rootFrame = dynamic_cast<Frame^>(Window::Current->Content);
rootFrame->Navigate(TypeName(MainPage::typeid), nullptr, ref new Animation::SuppressNavigationTransitionInfo);
}, concurrency::task_continuation_context::use_current());
}
Related
I am using MVVMCross 3.2.2 as part of an iOS/Android app. One of my screens has multiple views that are displayed depending upon the selection in a Tab bar like row of buttons. Different data is displayed in each of these these views individual UITableView. The data binding works perfectly.
I also have a menu, that has a "profile" selection. Changing the profile fires an MvxMessage that my HomeView receives and then uses the message to set the ViewModel up to filter the data to be displayed. This all seems to work perfectly and the data is displayed correctly.
If I do something in the HomeView that displays another view using ShowViewModel(). When I return back to the home view the binding no longer works properly when a profile changes is made. The message gets handled, the data gets filtered, but a call to ReloadDataTable on the UITableView does not change the data.
ViewModel
#region Groupings
public IList<Group> Groups{
get { return _groupService.GetAll(); }
}
public void SetupSubGroups(Group group)
{
if (group == null)
{
_groups = new ObservableCollection<Group> ();
if (_profileService.SelectedProfile != null)
{
var grp = _groupService.GetByGroupName (_profileService.SelectedProfile.Name);
if (grp == null)
grp = new Group { Name = _profileService.SelectedProfile.Name };
_groups.Add (grp);
}
}
else
{
var litsOfGroups = _groupService.GetSubGroups (group);
foreach (var grp in litsOfGroups)
_groups.Add (grp);
}
RaisePropertyChanged(() => AvailableGroups);
}
private ObservableCollection <Group> _groups;
public ObservableCollection<Group> AvailableGroups {
get { return _groups; }
}
#endregion
ViewController
public override void ViewDidLoad ()
{
base.ViewDidLoad ();
var groupSource = new GroupTableViewDataSource (TableViewGroups);
TableViewGroups.Source = groupSource;
_localViewModel.SetupSubGroups (null);
_bindingSet = this.CreateBindingSet<HomeViewController, HomeViewModel> ();
_bindingSet.Bind (groupSource).To (vm => vm.AvailableGroups);
_bindingSet.Apply ();
TableViewReportTags.ReloadData ();
NavigationController.NavigationBarHidden = false;
}
private void OnProfileChanged(ProfileChangedMessage message)
{
_localViewModel.SetupSubGroups (null);
TableViewGroups.ReloadData ();
}
private HomeViewModel _localViewModel { get { return ViewModel as HomeViewModel; } }
Any ideas what I can look at, or change would be really useful. I have spend many hours on this, and have made no progress.
I am trying to create a Waveform Control Panel to change the properties of its components. I attempted to apply the example in the Redhawk documentation for a Component Control Panel, but for some reason I get a java.lang.NullPointerException when running the plugin. The error occurs when I attempt to bind the text field to a component property, the exact line where the error occurred is in the comments of the code (at the very bottom).
public class TestControlPanel extends AbstractScaContentEditor<ScaWaveform> {
private ScaWaveform waveform;
private ScaComponent myComponent;
private Text propertyValueField;
private EMFDataBindingContext context;
/**
* {#inheritDoc}
*/
#Override
public void createPartControl(final Composite main) {
main.setLayout(new GridLayout(2, false));
Group controlGroup = new Group(main, SWT.SHADOW_ETCHED_OUT);
controlGroup.setLayoutData(GridDataFactory.fillDefaults().grab(true, true).create());
controlGroup.setText("Controls");
createControlGroup(controlGroup);
}
private void createControlGroup(Composite parent) {
parent.setLayout(new GridLayout(2, false));
EObject input = getInput();
if (input instanceof ScaWaveform) {
// make local copy of waveform
waveform = (ScaWaveform) input;
try {
waveform.refresh(null, RefreshDepth.FULL);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
label = new Label(parent,SWT.None);
label.setText("Property Value:");
propertyValueField = new Text(parent, SWT.BORDER | SWT.FILL);
myComponent = waveform.getScaComponent("myComponent_1");
if(myComponent != null)
{
IObservableValue observable = SCAObservables.observeSimpleProperty(myComponent, "propertyId");
IObservableValue targetObservable = WidgetProperties.text(SWT.Modify).observeDelayed(5000,propertyValueField);
if(observable != null && targetObservable != null)
{
// ***** THE BELOW LINE CAUSES A java.lang.NullPointerException ERROR *****
context.bindValue(targetObservable, observable);
// ***** THE ABOVE LINE CAUSES A java.lang.NullPointerException ERROR *****
}
}
}
}
My original guess for the reason for this error was that one of the IObservableValue variables (e.g. targetObservable or observable) was null, which is why I check to make sure the values are not null before binding them. However, this didn't fix the problem and I still got the same error.
From what code I can see it seems as though your field varible "context" was never initialized.
Simply call the no argument constructor:
context = new EMFDataBindingContext();
It appears that the context variable is null. I see that you define "context" at the top of the class, but I didn't see where it has been set.
I'm creating my own IntelliSense Presenter, since Visual Studio2012 support change theme, so I want my background color of the presenter can be auto-changed when the theme been changed. Is there a way to track the theme changes event, or get the current color theme of the Visual Studio?
Yes, this is possible. I had to solve a similiar issue with one of my extensions...
The current theme is stored in the Windows Registry; so I implemented the following utility class.
public enum VsTheme
{
Unknown = 0,
Light,
Dark,
Blue
}
public class ThemeUtil
{
private static readonly IDictionary<string, VsTheme> Themes = new Dictionary<string, VsTheme>()
{
{ "de3dbbcd-f642-433c-8353-8f1df4370aba", VsTheme.Light },
{ "1ded0138-47ce-435e-84ef-9ec1f439b749", VsTheme.Dark },
{ "a4d6a176-b948-4b29-8c66-53c97a1ed7d0", VsTheme.Blue }
};
public static VsTheme GetCurrentTheme()
{
string themeId = GetThemeId();
if (string.IsNullOrWhiteSpace(themeId) == false)
{
VsTheme theme;
if (Themes.TryGetValue(themeId, out theme))
{
return theme;
}
}
return VsTheme.Unknown;
}
public static string GetThemeId()
{
const string CategoryName = "General";
const string ThemePropertyName = "CurrentTheme";
string keyName = string.Format(#"Software\Microsoft\VisualStudio\11.0\{0}", CategoryName);
using (RegistryKey key = Registry.CurrentUser.OpenSubKey(keyName))
{
if (key != null)
{
return (string)key.GetValue(ThemePropertyName, string.Empty);
}
}
return null;
}
}
Okay; this just helps to figur out the current settings... listening for the theme changed notification is a bit trickier. After your package is loaded, you must obtain an IVsShell instance via the DTE; once you have this object you can utilize the AdviceBroadcastMessages method to subscribe for event notifications. You have to provide an object whose type implements the IVsBroadcastMessageEvents interface...
I don´t want to post the whole implementation, but the following lines might illustrate the key scenario...
class VsBroadcastMessageEvents : IVsBroadcastMessageEvent
{
int IVsBroadcastMessageEvent.OnBroadcastMessage(uint msg, IntPtr wParam, IntPtr lParam)
{
const uint WM_SYSCOLORCHANGE = 0x15;
if (msg == WM_SYSCOLORCHANGE)
{
// obtain current theme from the Registry and update any UI...
}
}
}
Consider implementing IDisposable on that type as well, in order to be able to unsubscribe from the event source, when the package gets unloaded.
This is how I subscribe for event notifications...
class ShellService
{
private readonly IVsShell shell;
private bool advised;
public ShellService(IVsShell shellInstance)
{
this.shell = shellInstance;
}
public void AdviseBroadcastMessages(IVsBroadcastMessageEvents broadcastMessageEvents, out uint cookie)
{
cookie = 0;
try
{
int r = this.shell.AdviseBroadcastMessages(broadcastMessageEvents, out cookie);
this.advised = (r == VSConstants.S_OK);
}
catch (COMException) { }
catch (InvalidComObjectException) { }
}
public void UnadviseBroadcastMessages(uint cookie)
{
...
}
}
Keep the value of the cookie parameter; you´ll need it to successfully unsubscribe.
Hope that helps (-:
Just wanted to put an update just in case anyone else comes along.. #Matze and #Frank are totally right.. However in VS 2015.. they added a easy way to detect the theme change. So you need to include PlatformUI an dyou get a super easy event
using Microsoft.VisualStudio.PlatformUI;
....
//Then you get an event
VSColorTheme.ThemeChanged += VSColorTheme_ThemeChanged;
You should make sure your control is disposable so you can unsubscribe from the event...
BONUS!
It also give you easy access to the colors.. even if the user has changed them from the default .. so you can do stuff like this in when set your colors
var defaultBackground = VSColorTheme.GetThemedColor(EnvironmentColors.ToolWindowBackgroundColorKey);
var defaultForeground = VSColorTheme.GetThemedColor(EnvironmentColors.ToolWindowTextColorKey);
For VS 2015 this has changed, the solution #Matze has still works but you need to update the GetThemeId() function to check for the version and if it's 14.0 (VS2015) look in a different place in the registry. The way the value is stored has changed also, it's still a string but now contains other values seperated by a '*'. The theme guid is the last value in the list.
if (version == "14.0")
{
string keyName = string.Format(#"Software\Microsoft\VisualStudio\{0}\ApplicationPrivateSettings\Microsoft\VisualStudio", version);
using (RegistryKey key = Registry.CurrentUser.OpenSubKey(keyName))
{
if (key != null)
{
var keyText = (string)key.GetValue("ColorTheme", string.Empty);
if (!string.IsNullOrEmpty(keyText))
{
var keyTextValues = keyText.Split('*');
if (keyTextValues.Length > 2)
{
return keyTextValues[2];
}
}
}
}
return null;
}
Below is a sample implementation that uses metro API and data binding (using MVVM) to populate list of folders in a drop down list.
The View model‘s constructor uses SetFolders method (private async), which calls an awaitable method fileService.GetFoldersAsync() to get list of folders. The folders list is then gets assigned to the property called “FoldersList”. XAML uses this property to populate a drop down list using the data binding.
I wonder is there a better way to set the FoldersList property without having to set it in the constructor as below. I would prefer to call the GetFilesAsync method and set the FilesList property value, when the actual data binding occurs (not during the class init). Since the properties do not support async/await modifiers (as far as I know) I’m struggling to implement a proper solution. Any ideas greatly appreciated.
The code is below.
ViewModel
public class FileViewModel : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private readonly IFileService fileService;
public FileDataViewModel(IFileService fileService)
{
this.fileService = fileService;
SetFolders();
}
private async void SetFolders ()
{
FoldersList = await fileService.GetFoldersAsync();
}
private IEnumerable< IStorageFolder > foldersList;
public IEnumerable<StorageFolder> FoldersList
{
get { return foldersList; }
private set
{
foldersList = value;
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs("FoldersList"));
}
}
}
}
IFileService and implementation
public interface IFileService {
Task<IEnumerable<IStorageFolder>> GetFilesAsync();
}
public class FileService : IFileService
{
public async Task<IEnumerable<IStorageFolder>> GetFoldersAsync()
{
var folder = KnownFolders.DocumentsLibrary;
return await folder.GetFoldersAsync();
}
}
I would implement it as a lazy property and use ObservableCollection<T> rather than IEnumerable<T>. We are doing it in several projects and it works well. This way you can guarantee that you are loading data only when needed. Furthermore, if you need to prefetch it, you can always call the load method in the constructor or elsewhere.
As a side note, I personnaly wouldn't expose IStorageFolder directly from my ViewModels.
private async Task LoadData()
{
if(!IsLoading)
{
IsLoading = true;
Folders = new ObservableCollection<Folder>(await fileService.GetFolderAsync());
}
IsLoading = false;
}
private ObservableCollection<Folder> _folders;
public ObservableCollection<Folder> Folders
{
get
{
if(_folders == null)
{
LoadData();//Don't await...
}
return _folders;
}
private set
{
SetProperty(ref _folders,value);
}
}
private bool _isLoading;
public bool IsLoading
{
get
{
return _isLoading;
}
private set
{
SetProperty(ref _isLoading,value);
}
}
Note that you can use the IsLoading property to display a progress ring for instance. after that the observable collection is loaded, you will be able to refresh it without recreating it. (_folders.Add, _folders.Remove, _folders.Clear...)
If I create a List based on an array of Commands, and the text of some Commands are not entirely shown in the List, although the List preferredWidth is set to the Form preferredWidth, how to ticker them ?
Thank you very much
Add the below class in your midlet class or create a new class file for that:
class TickerRenderer extends DefaultListCellRenderer {
private DefaultListCellRenderer selectedRenderer = new DefaultListCellRenderer(false);
private List parentList;
public TickerRenderer() {
super(false);
}
public boolean animate() {
if (parentList != null && parentList.getComponentForm() != null) {
if (selectedRenderer.isTickerRunning()) {
if (selectedRenderer.animate()) {
parentList.repaint();
}
}
}
return super.animate();
}
public Component getListCellRendererComponent(List list, Object value, int index, boolean isSelected) {
if (isSelected) {
selectedRenderer.getListCellRendererComponent(list, value, index, isSelected);
// sometimes the list asks for a dummy selected value for size calculations and this might
// break the tickering state
if (index == list.getSelectedIndex()) {
if (selectedRenderer.shouldTickerStart()) {
if (!selectedRenderer.isTickerRunning()) {
parentList = list;
list.getComponentForm().registerAnimated(this);
selectedRenderer.startTicker(UIManager.getInstance().getLookAndFeel().getTickerSpeed(), true);
}
} else {
if (selectedRenderer.isTickerRunning()) {
selectedRenderer.stopTicker();
}
}
}
return selectedRenderer;
} else {
return super.getListCellRendererComponent(list, value, index, isSelected);
}
}
}
Use it like this:
List cmdList = new List(cmds);
cmdList.setListCellRenderer(new TickerRenderer());
Try this code, it will show list in dialog box on clicking "Show list" command and will also enable ticker initially. Below is the code which shows how to use the above mentioned class to see ticker in list when list is contained in dialog.
Don't forget to make your list final so that it can be used in inner classes.
form.addCommand(new Command("Show list") { // add command in form and override its actionPerformed method
public void actionPerformed(ActionEvent evt) {
Dialog d = new Dialog() { // create an instance of dialog and make it an inner class so that you can override onShow() method and set focus on list when dialog gets initialized and also can set its index to ur preferred one (here it's 0)
protected void onShow() { // overriding of onShow() method
list.requestFocus(); // set focus on list
list.setSelectedIndex(0); // set selected index to 0
}
};
d.addComponent(list); // add list in dialog
d.show(); // show dialog
}
});
This code shows my list in dialog and starts ticker initially. If it doesn't help, post your code, i will try to see it.