当我尝试保存此模型时,该menu.Roles
字段始终为null
,并且保存更改方法不会更改该Roles
字段
表是Menu
,RoleMenu
并且Role
所以,我有一对多 2 多模型:
菜单有一个Roles
字段
角色有一个Menus
字段
动作方法:
[HttpPost]
public ActionResult Edit(Menu menu, IEnumerable<int> RoleIDs)
{
if (ModelState.IsValid)
{
var roles = _db.UserRoles.Where(rl => RoleIDs.Contains(rl.Id)).ToList();
menu.Roles = new List<UserRole>();
menu.Roles.AddRange(roles);
_db.Entry(menu).State = EntityState.Modified;
_db.SaveChanges();
return RedirectToAction("Index");
}
ViewBag.ParentMenuId = new SelectList(_db.Menus, "Id", "Name", menu.ParentMenuId);
ViewBag.RoleIDs = new SelectList(_db.UserRoles.ToList(), "Id", "Name");
return View(menu);
}
看法:
//...other VS auto generated fields...
<div class="editor-label">
@Html.LabelFor(model => model.Roles, "Roles")
</div>
<div class="editor-field">
@Html.ListBox("RoleIDs")
@Html.ValidationMessageFor(model => model.Roles)
</div>
<p>
<input type="submit" value="Save" />
</p>
映射:
modelBuilder.Entity<Role>()
.HasMany(role => role.Menus)
.WithMany(menu => menu.Roles)
.Map(m =>
m.MapLeftKey("RoleId").
MapRightKey("MenuId").
ToTable("RoleMenu"));