Question

i，实际上想要显示角色名称来代替角色ID 所以我这样做这些是我的模特

    [Table("User")]
public class User
{
    [Key]
    [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
    public int UserId { get; set; }
    [Required(ErrorMessage = "Please Provide Fullname", AllowEmptyStrings = false)]
    [Display(Name = "Full Name")]
    public string Full_Name { get; set; }
    [Required(ErrorMessage = "Please Provide Username", AllowEmptyStrings = false)]
    public string Username { get; set; }
    [Required(ErrorMessage = "Please provide password", AllowEmptyStrings = false)]
    [DataType(System.ComponentModel.DataAnnotations.DataType.Password)]
    public string Password { get; set; }
    [Required(ErrorMessage = "Please Select User type", AllowEmptyStrings = false)]
    [Display(Name = "USER TYPE")]
    public int ROLEID { get; set; }
    [Required(ErrorMessage = "Please Select Login Status", AllowEmptyStrings = false)]
    [Display(Name = "Login Status")]
    public string Login_Status { get; set; }
    public List<Role> role { get; set; }
    UserDB db = new UserDB();
    public Role getname(int id) {
        return db.roles.SingleOrDefault(d => d.ROLEID == id);
    }
}
    [Table("ROLE")]
public class Role
{
    public int ROLEID { get; set; }
    public string ROLENAME { get; set; }
}

public class UserRole 
{
    public List<User> Ruser { get; set; }
    public List<Role> Rrole { get; set; }
}

这是我的控制器

        public ActionResult Userlist(int? page)
    {
        UserDB dc = new UserDB();
        List<User> users = dc.users.ToList();
        UserRole userrole = new UserRole();
        userrole.Ruser = users;
        return View(userrole);
    }

这是我的观点

 @model PHARMACY.Models.UserRole  


<table class="table table-striped table-hover ">
    <tr>
        <th>
            @Html.DisplayNameFor(model => model.Ruser.First().Full_Name)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.Ruser.First().Username)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.Ruser.First().Password)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.Rrole.First().ROLENAME)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.Ruser.First().Login_Status)
        </th>
        <th></th>
    </tr>

@foreach (var item in Model.Ruser) {
    <tr>
        <td>
            @Html.DisplayFor(modelItem => item.Full_Name)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.Username)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.Password)
        </td>
        <td>
            @{
            var name = Model.Rrole.Where(i => i.ROLEID == item.ROLEID);
            @Html.DisplayFor(m => m.Rrole.Where(i => i.ROLEID == item.ROLEID).FirstOrDefault());
            }       
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.Login_Status)
        </td>
        <td>
            <p class="label label-info">@Html.ActionLink("Edit", "EditUser", new { id=item.UserId,})</p> |
            <p class="label label-danger">@Html.ActionLink("Delete", "DeleteUser", new { id=item.UserId })</p>
        </td>
    </tr>
}

</table>

但它通过错误“值不能为空。参数名称：source“

Answer 1

如果您的数据库中没有用户，此行将导致错误：

@Html.DisplayNameFor(model => model.Ruser.First().Full_Name)

您没有处理model.Ruser为空的情况。

在视图中显示角色名称时出错

1 个答案: