var tempItem = (SitecoreIndexableItem)item;
ContentSearchManager.GetIndex("sitecore_products_index").Refresh(tempItem);
<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/">
$(id)$(id) <sitecore>
<contentSearch>
<configuration type="Sitecore.ContentSearch.ContentSearchConfiguration, Sitecore.ContentSearch">
<indexes hint="list:AddIndex">
<index id="sitecore_products_index" type="Sitecore.ContentSearch.LuceneProvider.LuceneIndex, Sitecore.ContentSearch.LuceneProvider">
<param desc="name">$(id)</param>
<param desc="folder">$(id)</param>
<!-- This initializes index property store. Id has to be set to the index id -->
<param desc="propertyStore" ref="contentSearch/indexConfigurations/databasePropertyStore" param1="$(id)" />
<configuration ref="contentSearch/indexConfigurations/defaultLuceneIndexConfiguration">
<indexAllFields>true</indexAllFields>
<fields hint="raw:AddComputedIndexField">
<field fieldName="Back Image" storageType="YES" indexType="TOKENIZED">Service.Lucene.ImageIndexField, Service</field>
<field fieldName="Front Image" storageType="YES" indexType="TOKENIZED">Service.Lucene.ImageIndexField, Service</field>
<field fieldName="ExternalID" storageType="YES" indexType="TOKENIZED">Service.Lucene.TextIndexFieldAddOn, Service</field>
<field fieldName="Brand" storageType="YES" indexType="TOKENIZED">Service.Lucene.TextIndexFieldAddOn, Service</field>
<field fieldName="Region" storageType="YES" indexType="TOKENIZED">Service.Lucene.TextIndexFieldAddOn, Service</field>
<field fieldName="Substrates" storageType="YES" indexType="TOKENIZED">Service.Lucene.TextIndexFieldAddOn, Service</field>
<field fieldName="Categories" storageType="YES" indexType="TOKENIZED">Service.Lucene.TreeListexIndexFieldAddOn, Service</field>
<field fieldName="Certification Icons" storageType="YES" indexType="TOKENIZED" patch:after="field[last()]">Service.Lucene.TreeListexIndexField, Service</field>
<field fieldName="Applications" storageType="YES" indexType="TOKENIZED" patch:after="field[last()]">Service.Lucene.TreeListexIndexField, Service</field>
</fields>
<fieldMap type="Sitecore.ContentSearch.FieldMap, Sitecore.ContentSearch">
<fieldNames hint="raw:AddFieldByFieldName">
<field fieldName="Page Title" storageType="YES" indexType="TOKENIZED" vectorType="YES" boost="1f" type="System.String"
settingType="Sitecore.ContentSearch.LuceneProvider.LuceneSearchFieldConfiguration, Sitecore.ContentSearch.LuceneProvider" />
<field fieldName="Product Number" storageType="YES" indexType="TOKENIZED" vectorType="YES" boost="1f" type="System.String"
settingType="Sitecore.ContentSearch.LuceneProvider.LuceneSearchFieldConfiguration, Sitecore.ContentSearch.LuceneProvider" />
<field fieldName="Short Description" storageType="YES" indexType="TOKENIZED" vectorType="YES" boost="1f" type="System.String"
settingType="Sitecore.ContentSearch.LuceneProvider.LuceneSearchFieldConfiguration, Sitecore.ContentSearch.LuceneProvider" />
<field fieldName="Full Description" storageType="YES" indexType="TOKENIZED" vectorType="YES" boost="1f" type="System.String"
settingType="Sitecore.ContentSearch.LuceneProvider.LuceneSearchFieldConfiguration, Sitecore.ContentSearch.LuceneProvider" />
<field fieldName="Features Description" storageType="YES" indexType="TOKENIZED" vectorType="YES" boost="1f" type="System.String"
settingType="Sitecore.ContentSearch.LuceneProvider.LuceneSearchFieldConfiguration, Sitecore.ContentSearch.LuceneProvider" />
<field fieldName="Patent Numbers" storageType="YES" indexType="TOKENIZED" vectorType="YES" boost="1f" type="System.String"
settingType="Sitecore.ContentSearch.LuceneProvider.LuceneSearchFieldConfiguration, Sitecore.ContentSearch.LuceneProvider" />
<field fieldName="Discontinued" storageType="YES" indexType="TOKENIZED" vectorType="YES" boost="1f" type="System.String"
settingType="Sitecore.ContentSearch.LuceneProvider.LuceneSearchFieldConfiguration, Sitecore.ContentSearch.LuceneProvider" />
<field fieldName="_uniqueid" storageType="YES" indexType="TOKENIZED" vectorType="YES" boost="1f" type="System.String"
settingType="Sitecore.ContentSearch.LuceneProvider.LuceneSearchFieldConfiguration, Sitecore.ContentSearch.LuceneProvider" />
</fieldNames>
</fieldMap>
</configuration>
<strategies hint="list:AddStrategy">
<!-- NOTE: order of these is controls the execution order -->
<strategy ref="contentSearch/indexConfigurations/indexUpdateStrategies/onPublishEndAsync" />
</strategies>
<commitPolicyExecutor type="Sitecore.ContentSearch.CommitPolicyExecutor, Sitecore.ContentSearch">
<policies hint="list:AddCommitPolicy">
<policy type="Sitecore.ContentSearch.TimeIntervalCommitPolicy, Sitecore.ContentSearch" />
</policies>
</commitPolicyExecutor>
<locations hint="list:AddCrawler">
<crawler type="Sitecore.ContentSearch.SitecoreItemCrawler, Sitecore.ContentSearch">
<Database>master</Database>
<Root>/sitecore/content/Products</Root>
</crawler>
</locations>
</index>
</indexes>
</configuration>
</contentSearch>
</sitecore>
</configuration>
