DBNull.Value not supportet?

[Zero-G.]

Hey

I use dotConnect for mySQL with the following code:

Code: Select all

Dim Groesse As Object = IIf(cmbGrösse.Value Is Nothing, DBNull.Value, cmbGrösse.Value)
            Dim Farbe As Object = IIf(cmbFarbe.Value Is Nothing, DBNull.Value, cmbFarbe.Value)
            Dim qArtikel = (From Query In LinqProvider.GetProvider.Artikelstamms _
                           Where Query.Invnr = Convert.ToString(cmbInvNr.Value) And _
                           Query.Lieferant = Convert.ToInt64(cmbLieferant.Value) And _
                           Query.Artikelnr = Convert.ToString(cmbArtNummer.Value) And _
                           Query.Groesse = Groesse And _
                           Query.Farbe = Farbe).Single

When either cmbFarbe.Value or cmbGroesse.Value = NOTHING, then I get an error, that

Method 'CompareObjectEqual' has no supported translation to SQL.

I also tried to set cmbGroesse.Value to "" when it is nothing, but "" is not equal to NULL

Any tip do this?

[AndreyR]

The IIf operator is not supported yet. I will let you know as soon as it is implemented.

[Zero-G.]

That wasn't the problem
I found out this moment.
Using this code:

Dim Groesse As Object = IIf(cmbGrösse.Value Is Nothing, DBNull.Value, cmbGrösse.Value)
Dim Farbe As Object = IIf(cmbFarbe.Value Is Nothing, DBNull.Value, cmbFarbe.Value)
Dim qArtikel = (From Query In LinqProvider.GetProvider.Artikelstamms _
Where Query.Invnr = Convert.ToString(cmbInvNr.Value) And _
Query.Lieferant = Convert.ToInt64(cmbLieferant.Value) And _
Query.Artikelnr = Convert.ToString(cmbArtNummer.Value) And _
Query.Groesse.Equals(Groesse) And _
Query.Farbe.Equals(Farbe)).Single

is working as I want