I have a 'save' function on my webform that will update an entity which has a byte array property for blob objects.  Everything works fine if I select all entity properties and then saving using this code:

Certification c = new Certification();

c.LoadByPrimaryKey(Convert.ToInt32(ViewState["cId"]));

//fill other properties here

byte[] bytes = new byte[RadUpload1.UploadedFiles[0].InputStream.Length];
RadUpload1.UploadedFiles[0].InputStream.Read(bytes, 0, Convert.ToInt32(RadUpload1.UploadedFiles[0].InputStream.Length));

c.File = bytes;

c.Save();

There is no reason to load the blob from the database if it isn't going to change or if I'm just going to overwrite that property and send the bytes back to the database.  What I'd like to be able to do is this:

Certification c = new Certification();

//load all properties except the blob
esQueryItem qi = new esQueryItem(c.Query, CertificationMetadata.ColumnNames.File, esSystemType.ByteArray);
c.Query.SelectAllExcept(qi).Where(c.Query.Id == Convert.ToInt32(ViewState["cId"]));
c.Query.Load();

//fill other properties here

byte[] bytes = new byte[RadUpload1.UploadedFiles[0].InputStream.Length];
RadUpload1.UploadedFiles[0].InputStream.Read(bytes, 0, Convert.ToInt32(RadUpload1.UploadedFiles[0].InputStream.Length));

c.File = bytes;

c.Save();

Unfortunately, when I try to assign 'bytes' to 'c.File' using my preferred method of using the 'SelectAllExcept' method, the property remains null and does not save.

Am I doing something wrong or is this just not possible for some reason.

Thanks is advance,

Paul

Okay, first we need to rewrite that query. I'm not sure where you got that sample from  as you should never have create esQueryItems like that, take a look at this:

Certification c = new Certification();

//load all properties except the blob
c.Query.SelectAllExcept(c.Query.File).Where(c.Query.Id == Convert.ToInt32(ViewState["cId"]));
c.Query.Load();

That's they way you want to write queries 

Now, as to the problem. The reason why it is failing is you didn't select the "File" column so when you go to access it there is no "File" DataColumn in the underlying DataTable. In 2+ years no one has ever ran into this.

You might try this though .... I used the Employees object from Northwind, it has a photo field, here I create the DataColumn if not present. This code is in my "Custom" class and I overload the Photo property.

namespace BusinessObjects
{
	public partial class Employees : esEmployees
	{
        public override byte[] Photo
        {
            get
            {
                return base.Photo;
            }
            set
            {
                if (this.Row != null)
                {
                    DataTable dt = this.Row.Table;

                    // If the DataColumn isn't present
                    if (!dt.Columns.Contains(EmployeesMetadata.ColumnNames.Photo))
                    {
                        // Create it
                        esColumnMetadata esCol = 
                            this.es.Meta.Columns.FindByColumnName(EmployeesMetadata.ColumnNames.Photo);

                        dt.Columns.Add(esCol.Name, esCol.Type);
                    }
                }

                base.Photo = value;
            }
        }
    }
}