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on the ITodoItemService interface, which will return true or false
depending on whether the update succeeded:
var successful = await _todoItemService.MarkDoneAsync(id);
if (!successful)
{
return BadRequest("Could not mark item as done.");
}
Finally, if everything looks good, the browser is redirected to the
/Todo/Index action and the page is refreshed.
With the view and controller updated, all that's left is adding the missing
service method.
Add a service method
First, add MarkDoneAsync to the interface definition:
Services/ITodoItemService.cs
Task<bool> MarkDoneAsync(Guid id);
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Then, add the concrete implementation to the TodoItemService :
Services/TodoItemService.cs
public async Task<bool> MarkDoneAsync(Guid id)
{
var item = await _context.Items
.Where(x => x.Id == id)
.SingleOrDefaultAsync();
if (item == null) return false;
item.IsDone = true;
var saveResult = await _context.SaveChangesAsync();
return saveResult == 1; // One entity should have been updated
}
This method uses Entity Framework Core and Where() to find an item
by ID in the database. The SingleOrDefaultAsync() method will either
return the item or null if it couldn't be found.
Once you're sure that item isn't null, it's a simple matter of setting the
IsDone property:
item.IsDone = true;
Changing the property only affects the local copy of the item until
SaveChangesAsync() is called to persist the change back to the database.
SaveChangesAsync() returns a number that indicates how many entities
were updated during the save operation. In this case, it'll either be 1 (the
item was updated) or 0 (something went wrong).
Try it out
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Run the application and try checking some items off the list. Refresh the
page and they'll disappear completely, because of the Where() filter in
the GetIncompleteItemsAsync() method.
Right now, the application contains a single, shared to-do list. It'd be
even more useful if it kept track of individual to-do lists for each user. In
the next chapter, you'll add login and security features to the project.
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