Question

MVC和Stackoverflow的新手很抱歉没有足够的声誉发布图片......

尝试使用预先选择的值

呈现ListBox

我的SQL数据库： http://i.imgur.com/bcdXyqE.png

我的实体框架 http://i.imgur.com/wYWXuAq.png

我的控制器

public ActionResult AccessRights(int id)
    {
        var user = db.User.Find(id);

        var roles = db.Role;

        var newList = new List<SelectListItem>();

        foreach (var role in roles)
        {
            newList.Add(
                new SelectListItem()
                {
                    Value = role.Id.ToString(),
                    Text = role.RoleName,
                    Selected = user.Role.Contains(role)
                }
            );
        }

        ViewBag.x = new SelectList(newList, "Value", "Text");

        ViewBag.Roles = new SelectList(db.Role, "Id", "RoleName", user.Role);

        return View(user);
    }

我的观点

<p>try1:</p>
@Html.ListBox("Roles", null, new { @class = "form-control", @size = 6, @style = "height: initial" })
<p>try2:</p>
@Html.ListBox("x", null, new { @size = 6, @style = "height: initial" })

使用预先选择的值渲染2次尝试中的非？

Answer 1

让它发挥作用。

public ActionResult AccessRights(int id)
    {
        var user = db.User.Find(id);

        IEnumerable<SelectListItem> roles = db.Role.Select(c => new SelectListItem{ Value = c.Id.ToString(), Text = c.RoleName, Selected = true});
        var rolesSelected = new int[user.Role.Count];
        var i = 0;
        foreach (var role in user.Role)
        {
            rolesSelected[i] = role.Id;
            i++;
        }

        ViewBag.Roles = roles.ToList();
        ViewBag.RolesSelected = rolesSelected;

        return View(user);
    }

@Html.ListBox("RolesSelect", new MultiSelectList(ViewBag.Roles, "Value", "Text", ViewBag.RolesSelected), new { @class = "form-control", @size = 6, @style = "height: initial" })

MVC ListBox选择的值

1 个答案: