Get/Set Values for Managed MetaData Field

Get Terms from the Field:

TaxonomyField commodityGrpFld = (TaxonomyField)web.Fields[“FieldName”];

       // get the Term Store ID from the field

       Guid commodityGrptermStoreId = commodityGrpFld.SspId;

       // Open a taxonomysession and get the correct termstore

       TaxonomySession session = new TaxonomySession(oSite);

       TermStore termStore = session.TermStores[commodityGrptermStoreId];               

       #region get terms from commodity termset

       try

       {

           TermSet termSetCommodity = termStore.GetTermSet(commodityGrpFld.TermSetId);                   

           if (termSetCommodity != null)

           {

               TermCollection CommodityTermColl = termSetCommodity.Terms;

               ArrayList commodityList = new ArrayList();

               foreach (Term commTerm in CommodityTermColl)

               {

                   commodityList.Add(commTerm.Name);

               }

//binding to listbox

               lbCommodityGrp.DataSource = commodityList;

               lbCommodityGrp.DataBind();

            }

        }

        catch (Exception)

        { }

        #endregion

Update the Item value for Managed Metadata field:

TaxonomyField taxoField_Commodity =spfile.Item.Fields[[“FieldName”] as TaxonomyField;

        TaxonomySession taxoSession = new TaxonomySession(oSite);

        TermStore store = taxoSession.TermStores[taxoField_Commodity.SspId];

        TermSet termSet = store.GetTermSet(taxoField_Commodity.TermSetId);

        if (taxoField_Commodity.AllowMultipleValues)

        {                                           

          TermCollection terms = termSet.GetAllTerms();

          List<string> taxonomyValueList = new List<string>();

          foreach (ListItem item in lbCommodityGrp.Items)

          {

            if (item.Selected)

            {

              taxonomyValueList.Add(item.Value);

            }

          }

          TaxonomyFieldValueCollection fieldValues = new TaxonomyFieldValueCollection(taxoField_Commodity);

          foreach (Term term in terms)

          {

             if (taxonomyValueList.Contains(term.Name))

             {

                TaxonomyFieldValue fieldValue = new TaxonomyFieldValue(taxoField_Commodity);

                fieldValue.TermGuid = term.Id.ToString();

                fieldValue.Label = term.Name;

                fieldValues.Add(fieldValue);

             }

          }

          taxoField_Commodity.SetFieldValue(spfile.Item, fieldValues);

       }

Get the Item value for Managed Metadata field:

                We need to convert the item value to TaxonomyFieldValueCollection