dice:

InvalidCastException: Object must implement IConvertible.]
System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream) +723
System.Data.SqlClient.SqlCommand.ExecuteNonQuery() +195
HPG.HP.garage.ProdDB.UpdateProdotti(Int32 productId, String ModelNumber, String ModelName, String ProductImage, String ThumbImage, Decimal UnitCost, Decimal netto, String description, Int32 Disponibilita, Int32 news, Int32 promo, Int32 CategoryId, Int32 IdFornitore, Int32 IdSubCat, Int32 iva)

come devo passare i campi?
ora sono così non li posso passare?
(TxtID.Text, _
CStr(Server.HtmlEncode(TxtCod.Text.Trim)), _
CStr(Server.HtmlEncode(TxtMod.Text.Trim)), _
CStr(Server.HtmlEncode(TxtImg.Text.Trim)), _
TxtThumb.Text.Trim, _
TxtRPrice.Text, _
TxtDprice.Text, _
TxtDesc.Text.Trim, _
TxtDispo.Text, _
ChkNews.Checked = 1, _
ChkPromo.Checked = 1, _
ddlcat.SelectedValue, _
DdlFor.SelectedValue, _
ddlsub.SelectedValue, _
DdlIva.SelectedValue)

ciao grz