Devexpress 排序对数据库表中不可用的某列无效

产品：Devexpress-eXpressApp框架

数据库：MSSQL（表示持久对象）

[C#]

表中提供了以下属性：FirstName、MiddleName、LastName
（正在进行排序）

在表中不可用：FullName（排序正常），myCustomProperties（排序不正常）

我想对网格中的所有列进行排序。你能帮我做点什么吗

[DefaultClassOptions]
[DefaultProperty("FullName")]
public class ABCTable : BaseObject
{
    string _firstName;
    string _middleName;
    string _lastName;

    public ABCTable (Session session) : base(session) { }

    [ImmediatePostData]
    [Size(100)]
    public string FirstName
    {
        get { return _firstName; }
        set { SetPropertyValue("FirstName", ref _firstName, value); }
    }

    [ImmediatePostData]
    [Size(100)]
    public string MiddleName
    {
        get { return _middleName; }
        set { SetPropertyValue("MiddleName", ref _middleName, value); }
    }

    [ImmediatePostData]
    [Size(150)]
    public string LastName
    {
        get { return _lastName; }
        set { SetPropertyValue("LastName", ref _lastName, value); }
    }

    [PersistentAlias("ISNULL(FirstName, '') + ' ' + ISNULL(MiddleName,'') + ' ' + ISNULL(LastName,'')")]
    public string FullName
    {
        get
        {
            return string.IsNullOrWhiteSpace(MiddleName) ? string.Format("{0} {1}", FirstName, LastName) : string.Format("{0} {1} {2}", FirstName, MiddleName, LastName);
        }
    }

  public int myCustomProperties
    {
        get { return 5;  }// Here big logic like use join of three tables and cal to count
    }

}