private void ValidateParentsAreParentless(Category category)
{
// There is no parent
if (category.ParentCategoryId == null)
return;
// The parent has a parent
Category parentCategory = _applicationDbContext.Categories.Find(category.ParentCategoryId);
if (parentCategory.ParentCategoryId != null)
throw new InvalidOperationException("You cannot nest this category more than two levels deep.");
// The parent does NOT have a parent, but the category being nested has children
int numberOfChildren = _applicationDbContext.Categories.Count(c => c.ParentCategoryId == category.Id);
if (numberOfChildren > 0)
throw new InvalidOperationException("You cannot nest this category's children more than two levels deep.");
}
private List<Category> GetListOfNodes()
{
List<Category> sourceCategories = _applicationDbContext.Categories.ToList();
List<Category> categories = new List<Category>();
foreach (Category sourceCategory in sourceCategories)
{
Category c = new Category();
c.Id = sourceCategory.Id;
c.CategoryName = sourceCategory.CategoryName;
if (sourceCategory.ParentCategoryId != null)
{
c.Parent = new Category();
c.Parent.Id = (int)sourceCategory.ParentCategoryId;
}
categories.Add(c);
}
return categories;
}
private string EnumerateNodes(Category parent)
{
// Init an empty string
string content = String.Empty;
// Add <li> category name
content += "<li class=\"treenode\">";
content += parent.CategoryName;
content += String.Format("<a href=\"/Categories/Edit/{0}\" class=\"btn btn-primary btn-xs treenodeeditbutton\">Edit</a>", parent.Id);
content += String.Format("<a href=\"/Categories/Delete/{0}\" class=\"btn btn-danger btn-xs treenodedeletebutton\">Delete</a>", parent.Id);
// If there are no children, end the </li>
if (parent.Children.Count == 0)
content += "</li>";
else // If there are children, start a <ul>
content += "<ul>";
// Loop one past the number of children
int numberOfChildren = parent.Children.Count;
for (int i = 0; i <= numberOfChildren; i++)
{
// If this iteration's index points to a child,
// call this function recursively
if (numberOfChildren > 0 && i < numberOfChildren)
{
Category child = parent.Children[i];
content += EnumerateNodes(child);
}
// If this iteration's index points past the children, end the </ul>
if (numberOfChildren > 0 && i == numberOfChildren)
content += "</ul>";
}
// Return the content
return content;
}
public async Task<ActionResult> Edit([Bind(Include = "Id,ParentCategoryId,CategoryName")] CategoryViewModel categoryViewModel)
{
if (ModelState.IsValid)
{
// Unwind back to a Category
Category editedCategory = new Category();
try
{
editedCategory.Id = categoryViewModel.Id;
editedCategory.ParentCategoryId = categoryViewModel.ParentCategoryId;
editedCategory.CategoryName = categoryViewModel.CategoryName;
ValidateParentsAreParentless(editedCategory);
}
catch (Exception ex)
{
ModelState.AddModelError("", ex.Message);
ViewBag.ParentCategoryIdSelectList = PopulateParentCategorySelectList(categoryViewModel.Id);
return View("Edit", categoryViewModel);
}
_applicationDbContext.Entry(editedCategory).State = EntityState.Modified;
await _applicationDbContext.SaveChangesAsync();
return RedirectToAction("Index");
}
ViewBag.ParentCategoryIdSelectList = PopulateParentCategorySelectList(categoryViewModel.Id);
return View(categoryViewModel);
}