I have a model that i created it bu EF6:
public partial class Comment
{
[DisplayName("شناسه نظر")]
public int Id { get; set; }
[Required(ErrorMessage = "متن نظر را وارد کنید")]
[DisplayName("متن نظر")]
public string CommentText { get; set; }
[DisplayName("تعداد پسندیدن ")]
public long LikeCount { get; set; }
[DisplayName("تعداد نپسندیدن")]
public long DisLikeCount { get; set; }
[DisplayName("تاریخ انتشار ")]
public System.DateTime PublishDate { get; set; }
[DisplayName("وضعیت نمایش ")]
public string Visible { get; set; }
[DisplayName("نام کاربری ")]
public Nullable<string> AutherUserName { get; set; }
[DisplayName("شناسه نظراصلی")]
public Nullable<int> CommentFKId { get; set; }
[DisplayName("شناسه کاربر")]
public Nullable<int> StudentId { get; set; }
[DisplayName("شناسه محتوا ")]
public Nullable<int> ContentId { get; set; }
public virtual Comment Comments { get; set; }
public virtual Comment Comment1 { get; set; }
public virtual Student Student { get; set; }
public virtual Content Content { get; set; }
}
As you can see i have several Nullable int columns in my model ,But i can't set a string column to null :
public Nullable<string> AutherUserName { get; set; }
And I got this error :
The type 'string' must be a non-nullable value type in order to use it as parameter 'T' in the generic type or method 'System.Nullable'
I am working with MVC4
Strings are reference types, so are already "nullable". Only value types (such as int) can be nullable as they can't otherwise be null.
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