Question

i have a mapped-class like this:

[Table("MyTable")]
class MyClass         
{   
        //properties; id, name, etc...

        private string _queuedToWHTime = string.Empty;
        [Column("QueuedToWHTime")]
        public string QueuedToWHTime
        {
            get { return _queuedToWHTime; }
            set { _queuedToWHTime = value; }
        }

        public DateTime? QueuedToWHTime_DateTime
        {
            get
            {
                if (!string.IsNullOrWhiteSpace(_queuedToWHTime))
                {
                    return Convert.ToDateTime(_queuedToWHTime);
                }
                return null;
            }
        }
}

and a table (MyTable):

CREATE TABLE webnews_in
(
Id                INT NOT NULL auto_increment,
QueuedToWHTime    VARCHAR (50) NULL
...
PRIMARY KEY (Id)
);

when i trying to query like this:

var searchRslt=(from m in queryableNews
    orderby m.QueuedToWHTime_DateTime descending
    select m).ToList();

I got a NotSupportedException:The specified type member ‘QueuedToWHTime_DateTime’ is not supported in LINQ to Entities. Only initializers, entity members, and entity navigation properties are supported.

Answer 1

You cannot query with EF on custom properties. The custom property cannot be translated in SQL.

You can do this to force the orderby to be done ‘in-memory’.

var searchRslt = queryableNews
    .AsEnumerable()
    .OrderBy(m => m.QueuedToWHTime_DateTime)
    .ToList();