Update ArcMap TOC symbology headings from a table

Summary

Steps to develop VBA code to update Table Of Contents (TOC) symbology headings from an INFO table prior to inserting a legend in a map document.

Procedure

1. Get a reference to the map document whose headings are to be changed.
   
   
   Dim pMxDocument As IMxDocument
   Set pMxDocument = ThisDocument
   Dim pMap As IMap
   Set pMap = pMxDocument.FocusMap
   
   
2. Get a list of all feature layers in the TOC.
   
   
   Dim pLayers As IEnumLayer
   Set pLayers = pMap.Layers
   Dim pFeatureLayer As IFeatureLayer
   Set pFeatureLayer = pLayers.Next
   
   
3. Create a pointer to an INFO file workspace.
   
   
   '++ Create a pointer to the data's workspace:
   Dim pWorkspaceFact As IWorkspaceFactory
   Set pWorkspaceFact = New ArcInfoWorkspaceFactory
   Dim pWorkspace As IWorkspace
   Set pWorkspace = pWorkspaceFact.OpenFromFile("c:\geodata\covers", 0)
   Dim pFeatureWorkspace As IFeatureWorkspace
   Set pFeatureWorkspace = pWorkspace
   
   
4. Use IFeatureWorkspace:OpenTable to open the INFO file as an ITable object; then, select all table rows using a Query Filter.
   
   
   Dim pInfoTable As ITable
   Set pInfoTable = pFeatureWorkspace.OpenTable("headings.lut")
   Dim pQueryFilter As IQueryFilter
   Set pQueryFilter = New QueryFilter
   pQueryFilter.WhereClause = "FIELD_OF_HEADING_NAMES <> ''"
   Dim pCursor As ICursor
   Set pCursor = pInfoTable.Search(pQueryFilter, False)
   Dim fieldindex As Long
   fieldindex = pCursor.FindField("field_of_heading_names")
   Dim pRow As IRow
   Set pRow = pCursor.NextRow
   
   
5. Loop through the TOC layers. You must loop through each layer because each layer can have multiple subheadings. Change each heading to the value from the heading field in the INFO table. Advance the cursor to the next table row and advance the loop to the next TOC heading.
   
   

   Code:
     Dim i As Integer
     Dim j As Integer
     Dim pLegendInfo As ILegendInfo
     Dim pLegendGroup As ILegendGroup
     Dim strMyHeading As String
     For i = 0 To pMap.LayerCount - 1
       Set pLegendInfo = pFeatureLayer
         For j = 0 To pLegendInfo.LegendGroupCount - 1
           Set pLegendGroup = pLegendInfo.LegendGroup(j)
           strMyHeading = pRow.Value(fieldindex)
           pLegendGroup.Heading = strMyHeading
           Set pRow = pCursor.NextRow
         Next j
         Set pFeatureLayer = pLayers.Next
     Next i
     pMxDocument.UpdateContents  

   
   
   

   Warning:
   Run this code before you insert a legend from the Insert menu. Since this code does not capture legend properties, running it after inserting the legend would not update the legend graphic and you'd have to be rebuild from scratch.  

   
   
   

   Note:
   This is not ESRI supported code. Use it at your own risk. Make a backup of your data before running this code and carefully check the output. This is just example code with no real error checking. It is meant to be a guide to develop code specific to your data inputs and desired outputs.