Asp.Net核心标识中的德语字符错误

Usermanager通过检查允许的字符列表中是否包含任何字符来验证用户名。您可以更改该列表：

services.Configure<IdentityOptions>(options =>
{
     // The list of allowed characters in the username used to validate user names 
     // you can add German characters here
     options.User.AllowedUserNameCharacters 
        = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-._@+";
});

services.AddIdentity<ApplicationUser, IdentityRole>()
       .AddEntityFrameworkStores<ApplicationDbContext>()
       .AddDefaultTokenProviders();