循环遍历角色并获取角色 MVC 6 首字母的控制器代码

Question

这是我的 UserViewModel：

public class UserViewModel
{
    public string UserId { get; set; }
    public string Email { get; set; }
    public string Roles { get; set; }
}

"Roles=RolePrefixes(u.Id)" 行是红色的。我已经尝试了一切来简单地调用 darn 函数。在我的控制器中，如何调用 RolePrefixes(string id) 函数？我说"function"因为我不知道该说什么。

  private List<UserViewModel> GetUsers()
    {

      var UserManager =  _serviceProvider.GetRequiredService<UserManager<ApplicationUser>>();
        var RoleManager = _serviceProvider.GetRequiredService<RoleManager<IdentityRole>>();
        var allRoles = RoleManager.Roles.ToList();
        //var user = UserManager.FindByIdAsync(userID);
        //var usersRoles = UserManager.GetRolesAsync(user);

        return context.Users.Select(u => new UserViewModel
        {
            Email = u.Email,
            UserId = u.Id,

           // THIS WORKS FOR Role Ids but not their Names::: Roles = String.Join("/", u.Roles.Select(r => r.RoleId.First()))


           Roles = RolePrefixes(u.Id) //THIS IS UNDERLINED IN RED.

        }).ToList();

    }


    public async Task<string> RolePrefixes(string id)
    {
        var UserManager = _serviceProvider.GetRequiredService<UserManager<ApplicationUser>>();
        //var RoleManager = _serviceProvider.GetRequiredService<RoleManager<IdentityRole>>();
        //var allRoles = RoleManager.Roles.ToList();
        var user = await UserManager.FindByIdAsync(id);
        var usersRoles = await UserManager.GetRolesAsync(user);

        string strPrefixes = "";
        foreach (var item in usersRoles)
        {
            strPrefixes += item + "/";

        }

        return strPrefixes;

    }

Answer 1

投射角色名称，select 字符串中的第一个字符，并将它们连接在一起。

return context.Users.Select(u => new UserViewModel
{
    Email = u.Email,
    UserId = u.Id,

    Roles = String.Join("/", context.Roles.Where(r => r.Users.Any(u2 => u2.UserId == u.Id)).Select(r => r.Name.First()))

}).ToList();

循环遍历角色并获取角色 MVC 6 首字母的控制器代码

Controller Code to Loop Through Roles and Get First Letter of Role MVC 6

c#

function

asp.net-mvc-5

asp.net-identity-2