HOW TO DELETE THE SYMBOL'S USING VB-API

HI EVERYONE,

I AM FACING FEW ISSUES WHILE I AM TRYING TO DELETE THE SYMBOL INSTANCES FROM CREO DRAWING TEMPLATE.

I WILL EXPLAIN IT BRIEFLY:

I HAVE A CREO DRAWING TEMPLATE WHICH IS HAVING MANY SYMBOLS FOR Eg: REVISION BALLOON, SURFACE FINISH etc.WHAT I WANT TO DO IS I WANT TO DELETE SOME SPECIFIC SYMBOL INSTANCES FROM THE DRAWING LIKE.

1. I HAVE SURFACE FINISH SYMBOLS FROM Ra0.6 TO Ra1.8 IN MY DRAWING BUT I WANT TO DELETE ONLY Ra1.8 FROM MY DRAWING.

2.SIMILARLY I HAVE REVISION BALLOON FROM A TO Z HERE TOO I WANT TO DELETE ONLY A SPECIFIC INSTANCE WHICH USER IS GONNA SELECT.

WITH THE HELP OF Mr Parthiban Kannan‌ I HAVE ALMOST REACHED THE LAST STAGE, BUT NOW I AM FACING ISSUE IN SELECTING THE INSTANCE OF THE SYMBOL.

BELOW GIVEN IS THE CODE:

Public Sub findsymbol(ByRef session As IpfcSession, _

                                   ByVal symbolname As String, _

                                   ByRef TextBox1 As String)

        Try

            Dim model As IpfcModel

            Dim drawing As IpfcModel2D

            Dim symInstructions As IpfcDetailSymbolInstInstructions

            Dim symItem As IpfcDetailSymbolInstItem

            model = session.CurrentModel

            drawing = CType(model, IpfcModel2D)

            Dim i As Long

            Dim TotalSheets As Long

            TotalSheets = drawing.NumberOfSheets

            i = drawing.CurrentSheetNumber

            For i = 1 To TotalSheets

                Dim owner As IpfcDetailItemOwner = CType(drawing, IpfcDetailItemOwner)

                Dim symbol As IpfcDetailSymbolDefItem = owner.RetrieveSymbolDefinition(symbolname, Nothing, Nothing, False)

                MessageBox.Show(symbol.GetInstructions.FullPath)

                symInstructions = symbol.ListDetailItems(EpfcDetailType.EpfcDETAIL_SYM_INSTANCE)

                symInstructions.TextValues = TextBox1                 (GETTING ERROR IN THIS LINE)

                symItem = symInstructions.TextValues

                symItem.Remove()

            Next

        Catch ex As Exception

            MsgBox(ex.Message.ToString + Chr(13) + ex.StackTrace.ToString)

        End Try

    End Sub

THIS IS HOW MY FORM LOOKS :

a) FIRST BOX IS FOR SYMBOL NAME

b) SECOND ONE IS FOR SYMBOL INSTANCE WHICH I WANT TO DELETE

ERROR WHAT I AM GETTING :

With Regards

Aghil.M