public SPField TryGetField(SPFieldCollection siteColumns, Guid fieldID)
        {
            siteColumns.RequireNotNull("siteColumns");
            fieldID.Require(Guid.Empty != fieldID, "fieldID");

            return siteColumns.Contains(fieldID) ? siteColumns[fieldID] : null;
        }
        public static SPFeature ActivateFeatureIfNecessary(SPWeb web, Guid featureGuid)
        {
            web.RequireNotNull("web");
            featureGuid.Require(Guid.Empty != featureGuid, "featureGuid");

            SPFeature feature = web.Features[featureGuid];
            if (null == feature)
            {
                feature = web.Features.Add(featureGuid);
            }

            return feature;
        }
        public static SPFeature ActivateFeatureIfNecessary(SPSite site, Guid featureGuid)
        {
            site.RequireNotNull("site");
            featureGuid.Require(Guid.Empty != featureGuid, "featureGuid");

            SPFeature feature = site.Features[featureGuid];
            if (null == feature)
            {
                feature = site.Features.Add(featureGuid);
            }

            return feature;
        }
        public static SPFeature ActivateFeatureIfNecessary(SPWeb web, Guid featureGuid, bool force, SPFeatureDefinitionScope sPFeatureDefinitionScope)
        {
            web.RequireNotNull("web");
            featureGuid.Require(Guid.Empty != featureGuid, "featureGuid");

            SPFeature feature = web.Features[featureGuid];
            if (null == feature || force)
            {
                feature = web.Features.Add(featureGuid, force, sPFeatureDefinitionScope);
            }

            return feature;
        }