I have revised your code to make it more efficient. Your code is slow because it uses repeated queries inside of a loop (it also was repeatedly doing a Dim of the Row variable inside the loop as well, which is a big no no. Never do a Dim inside of a loop).I realized that since you are accessing the same SelectionSet for the same parent feature class through the same layer that you do not need to use a queryfilter in the loop to synchronize the reading of the parent feature class and the joined table. To prove that the cursors on the unjoined featureclass and the joined displaytable are running in synch, I substituted reading the parent table ObjectID feilds in the code below. You can revise this code back to replacing the fields with your original fields (again if all you want to do is just read the joined data, just use the display table SelectionSet together with either the ParentTableName.FieldName or JoinTableName.FieldName formats for the fields you want to read).Now ideally this code could be further modified to use an efficient method that would substitute an update cursor for reading through the SelectionSet of the parent feature class instead of using a search cursor. That way the code would allow reading of data from the joined displaytable and writing to the features of the parent FeatureClass in a single pass, with efficiency that is similar to using a FieldCalculator with a VBA or VB Script expression on a joined table.Public Sub GetLayerSelection2()
Dim pMxDoc As IMxDocument
Set pMxDoc = ThisDocument
Dim pFLayer As IFeatureLayer
Set pFLayer = pMxDoc.FocusMap.Layer(0) 'Get first layer
Dim pDisplayTable As IDisplayTable
Set pDisplayTable = pFLayer
If Not TypeOf pDisplayTable.DisplayTable Is IRelQueryTable Then
MsgBox "Feature Layer is not joined! Exiting Sub."
Exit Sub
End If
Dim pSelSet As ISelectionSet
Set pSelSet = pDisplayTable.DisplaySelectionSet
Dim pCount As Long ' Use Integer only if this is VB.Net and not VBA.
pCount = pSelSet.Count
If pCount > 5 Then
MsgBox "Too many features selected. Please select 5 or less." 'Was quite slow, but now probably no longer necessary
Exit Sub
End If
Dim pTableCursor As ICursor
pSelSet.Search Nothing, True, pTableCursor
Dim pRow As IRow
Set pRow = pTableCursor.NextRow
Dim pFSel As IFeatureSelection
Set pFSel = pFLayer
Dim pSelSet2 As ISelectionSet
Set pSelSet2 = pFSel.SelectionSet
Dim pFCursor As IFeatureCursor
pSelSet2.Search Nothing, True, pFCursor
Dim pFeature As IFeature
Set pFeature = pFCursor.NextFeature
Dim pTableIndex As Long
pTableIndex = pDisplayTable.DisplayTable.Fields.FindField("ParentTableName.OBJECTID") ' Substitute the actual ParentTableName or use JoinTableName.FieldName
If pTableIndex = -1 Then
MsgBox "ParentTableName.OBJECTID Field Not Found! Exiting Sub." ' Substitute the appropriate message.
Exit Sub
End If
Dim pFeatureIndex As Long
pFeatureIndex = pFeature.Fields.FindField("OBJECTID")
If pFeatureIndex = -1 Then
MsgBox "OBJECTID Field Not Found! Exiting Sub."
Exit Sub
End If
Do Until pFeature Is Nothing ' Keep your loop as tight as possible and do not do Dim statements inside of it.
Debug.Print pFeature.Value(pFeatureIndex) & " = " & pRow.Value(pTableIndex) ' report value of field in join table
Set pRow = pTableCursor.NextRow
Set pFeature = pFCursor.NextFeature
Loop
End Sub
