/// <summary>
/// Creates a new dialog window that allows a user to edit a specific inventory item.
/// </summary>
/// <param name="item">The inventory item being edited.</param>
public void ModifyItem(BaseInventoryModel item)
{
// Get the type of view model we are creating.
Type viewModelType;
// Get the type of model we need.
if (item is MovieModel)
{
viewModelType = typeof(MovieModel);
}
else if (item is BookModel)
{
viewModelType = typeof(BookModel);
}
else if (item is VideoGameModel)
{
viewModelType = typeof(VideoGameModel);
}
else
{
throw new ArgumentOutOfRangeException(nameof(viewModelType), @"Unknown type for inventory model");
}
// Resolve (create) the view model.
if (!(App.ServiceProvider.GetService(viewModelType) is BaseInventoryModel viewModel))
{
return;
}
// Copy the item's properties into the new model.
viewModel.CopyFrom(item);
// Create a new button to save changes to the item.
UICommand saveChangesCommand = new UICommand()
{
Caption = "Save",
IsDefault = true,
// Only allow the user to save their changes if there are no errors in the data entry.
Command = new DelegateCommand(
() => { },
() => string.IsNullOrEmpty(viewModel.Error)
)
};
// Create a new button that cancels and closes the dialog window for modifying an item.
UICommand cancelCommand = new UICommand()
{
Caption = "Cancel",
IsCancel = true,
};
// Display the dialog window.
UICommand result = AddOrModifyItemDialogService?.ShowDialog(
dialogCommands: new[] { saveChangesCommand, cancelCommand },
title: "Modify an Item",
viewModel: viewModel
);
// Check if the user executed the save command (clicked the save button).
if (result != saveChangesCommand)
{
return;
}
// Copy the properties from the item we modified back into the original inventory item.
item.CopyFrom(viewModel);
}
// NOTE: The DevExpress POCO mechanism generates commands for all public methods without parameters or with a single parameter by convention.
// Corresponding delegate command properties are created using the names of public methods with the suffix "Command".
/// <summary>
/// Creates a new dialog window that allows the user to add an item.
/// </summary>
/// <param name="itemType">The type of item is bound to the the tab the user is on (i.e adding from the movie tab creates a new movie).</param>
public void AddItem(InventoryItemType itemType)
{
// Get the type of view model we are creating.
Type viewModelType;
switch (itemType)
{
case InventoryItemType.Book:
viewModelType = typeof(BookModel);
break;
case InventoryItemType.Movie:
viewModelType = typeof(MovieModel);
break;
case InventoryItemType.VideoGame:
viewModelType = typeof(VideoGameModel);
break;
// Throw an exception if our item type does not match any of the models.
default:
throw new ArgumentOutOfRangeException();
}
// Resolve (create) the view model.
if (!(App.ServiceProvider.GetService(viewModelType) is BaseInventoryModel viewModel))
{
return;
}
// Create a new button that adds the item.
UICommand addItemCommand = new UICommand()
{
Caption = "Add",
IsDefault = true,
// Only allow the user to add the item if there are no errors with the data entry.
Command = new DelegateCommand(
() => { },
() => string.IsNullOrEmpty(viewModel.Error)
)
};
// Create a new button that cancels and closes the dialog window for adding an item.
UICommand cancelCommand = new UICommand()
{
Caption = "Cancel",
IsCancel = true,
};
// Display the dialog window.
UICommand result = AddOrModifyItemDialogService?.ShowDialog(
dialogCommands: new[] { addItemCommand, cancelCommand },
title: "Add a New Item",
viewModel: viewModel
);
// Check if the user executed the add command (clicked the add button).
if (result != addItemCommand)
{
return;
}
// Add the new model based on the type of item we are adding.
switch (itemType)
{
case InventoryItemType.Book:
BookModels.Add(viewModel as BookModel);
break;
case InventoryItemType.Movie:
MovieModels.Add(viewModel as MovieModel);
break;
case InventoryItemType.VideoGame:
VideoGameModels.Add(viewModel as VideoGameModel);
break;
// Throw an exception if our item type does not match any of the models.
default:
throw new ArgumentOutOfRangeException();
}
// Highlight the newly added item.
FocusedItemModel = viewModel;
}