the method readmultiple

Here is an example which includes ItemNo and VariantCode filters:

ItemVariant itemVariant = new ItemVariant();
ItemVariant_Binding itemVariantBind = new ItemVariant_Binding();
NAVConn.PrepVrntBinding(ref itemVariantBind);
List<ItemVariant_Filter> filterArray = new List<ItemVariant_Filter>();
ItemVariant_Filter itemFilter = new ItemVariant_Filter();
ItemVariant_Filter variantFilter = new ItemVariant_Filter();

itemFilter.Field = ItemVariant_Fields.Item_No;
itemFilter.Criteria = itemNo;
filterArray.Add(itemFilter);

if (variantCode != null)
{
variantFilter.Field = ItemVariant_Fields.Code;
variantFilter.Criteria = variantCode;
filterArray.Add(variantFilter);
}

return itemVariantBind.ReadMultiple(filterArray.ToArray(), null, 0);