/// <summary>
/// Create the navigation structure containing all ViewModels
/// </summary>
/// <param name="mainViewModels">An array of the application's ViewModels</param>
private void LoadNavigation(ViewModelFoundation[] mainViewModels) {
// Browse every ViewModels and search if it has a Navig attribute
foreach(var vm in mainViewModels) {
foreach(NavigAttribute na in vm.GetType().GetCustomAttributes(typeof(NavigAttribute), inherit: false)) {
NavigConfig mainConf;
// Check if it already exists a NavigConf with the same name
var existingMainConf = navStructure.SingleOrDefault(n => n.Name == na.MainConfig.Name);
if(existingMainConf != null) // If it's the case, set mainConf to it
mainConf = existingMainConf;
else { // Else we use the MainConfig as a new elem of navStructure
if(!vm.IsAuthorized(CurrentUser))
na.MainConfig.Enabled = false;
mainConf = na.MainConfig;
navStructure.Add(mainConf);
}
// Assign the VM to the SubConfig or the main (if NavigAttribute has a single param)
if(na.SubConfig != null) {
if(!vm.IsAuthorized(CurrentUser))
na.SubConfig.Enabled = false;
na.SubConfig.VM = vm;
mainConf.SubConfig.Add(na.SubConfig);
} else
mainConf.VM = vm;
}
}
CurrentMainNav = MainNavig[0];
CurrentViewModel = SubNavig[0].VM;
CurrentMainNav.IsSelected = true;
SubNavig[0].IsSelected = true;
}
/// <summary>
/// Instanciate the ApplicationViewModel. All registred ViewModels are injected into the param mainViewModels
/// </summary>
/// <param name="mainViewModels">An array of the application's ViewModels (injected)</param>
/// <param name="loadingVm">The ViewModel representing the loading (injected)</param>
/// <param name="authVm">The ViewModel representing the authentication (injected)</param>
/// <param name="navConfs">An array containing the navigation configuration (injected)</param>
public ApplicationViewModel(ViewModelFoundation[] mainViewModels, ViewModelFoundation loadingVm, ViewModelFoundation authVm, NavigConfig[] navConfs) {
// Set the callback when the CurrentUser object has finished loading
CurrentUser.AsyncLoadingFinished += (s, a) => {
LoadNavigation(mainViewModels);
RaisePropertyChanged("MainNavig");
};
CurrentViewModel = authVm; // Display the authentication view
CurrentUser.AsyncLogin(); // Asynchronously log the user in
loadingViewModel = loadingVm;
// Load custom navigation informations
NavigAttribute.RegisterConfigurations(navConfs);
changeMainCmd = new Lazy<ICommand>(() =>
new RelayCommand<NavigConfig>(nc => CurrentMainNav = nc));
changeViewCmd = new Lazy<ICommand>(() =>
new RelayCommand<ViewModelFoundation>(vm => CurrentViewModel = vm));
}
/// <summary>
/// Sets the view as a loading one and execute asynchronously the PreLoad method of IPreLoadable.
/// Once loaded, it replaces the loading view by the freshly loaded ViewModel
/// </summary>
/// <param name="vm"></param>
private async void AsyncLoadViewModel(IPreLoadable vm) {
vm.IsPreLoadNeeded = false; // This ViewModel doesn't need loading anymore
nowLoadingViewModel = currentViewModel; // Set the currently loading ViewModel
currentViewModel = loadingViewModel; // Display the loading view
vm.IsCurrentlyLoading = true;
await Task.Factory.StartNew(vm.PreLoad); // Launch the preloading in another task
vm.IsCurrentlyLoading = false;
// Check if the view is a ILoadingViewModel and if it's currently in a loading state
if(nowLoadingViewModel != null && !(nowLoadingViewModel as IPreLoadable).IsCurrentlyLoading) {
currentViewModel = nowLoadingViewModel; // Replace the loading by the freshly loaded ViewModel
nowLoadingViewModel = null;
RaiseViewModelDisplayed(currentViewModel);
RaisePropertyChanged("CurrentViewModel");
}
}
/// <summary>
/// Raise a ViewModelDisplayed event to alert the subscribers that a new ViewModel
/// has been loaded into the application
/// </summary>
/// <param name="sender">The ViewModel that will be displayed</param>
protected virtual void RaiseViewModelDisplayed(ViewModelFoundation sender)
{
EventHandler handler = sender.ViewModelDisplayed;
if(handler != null)
handler(sender, EventArgs.Empty);
}