Question

I have added my table “tblFile” to my .dbml , but it’s type is “EntitySet tblFiles

But for another table with the same Association, its type is “tblDocTranstoCon”
So I have problem in the below linq query “w” is not IEnumerable but “z” is “IEnumerable”

z = document.tblTransmittalls.Select(dp => dp.tblDocTranstoCons),
w = document.tblTransmittalls.Select(dx => dx.tblFiles)

How I can solve this problem for producing IEnumerable.

[Association(Name="tblTransmittall_tblFile", Storage="_tblFiles", ThisKey="DocID,TransId", OtherKey="DocId,TransId")]
public EntitySet<tblFile> tblFiles
{
    get
    {
        return this._tblFiles;
    }
    set
    {
        this._tblFiles.Assign(value);
    }
}

[Association(Name="tblTransmittall_tblDocTranstoCon", Storage="_tblDocTranstoCons", ThisKey="DocID,TransId", OtherKey="Docid,Transid", IsUnique=true, IsForeignKey=false)]
public tblDocTranstoCon tblDocTranstoCons
{
    get
    {
        return this._tblDocTranstoCons.Entity;
    }

Answer 1

You should try this

w = document.tblTransmittalls.SelectMany(dx => dx.tblFiles);

because tblFiles has return type EntitySet<tblFile> (which is a Collection) whereas tblDocTranstoCons has return type tblDocTranstoCon

or you should change its association in dbml designer.