How to check for a row and remove it based on a commandfield click

Ok, I am not sure how I can undo my creation of rows based on the user clicking my image button.

So far, what works, is when the user clicks on the commandfield control below in my GridView, the images changes to a minus (hence collapses the gridview row to reveal it's detailed row which is newly created by my CreateRow method below)

<asp:commandfield  buttontype="Image" selectimageurl="/images/plus.gif" showselectbutton="True" />

When the user clicks the control again, the image goes back to plus.  I am not sure how to:

a) capture if the user has expanded or collapsed since there is no ID attribute on a commandfield that I can grab onto to maybe do something like a check on the image to determine that
b) How to check if the CreateRow created a row before and undo it if it has...hence collapse

I am new to commandfield so bare with me.  Here's the function that actually creates the row, underneath the current row that the user has selected (selected mean by clicking on the commandfield image which changes form a plus to minus icon or vice versa when clicked)

    Private Sub CreateRow(ByVal table As Table, ByVal index As Integer)
        Dim row As GridViewRow = New GridViewRow(-1, -1, DataControlRowType.DataRow, DataControlRowState.Normal)
        Dim selectedrow As GridViewRow = SearchResults.Rows(index)
        Dim StfID As Integer = SearchResults.DataKeys(index).Value
        row.Cells.Add(CreateColumn(StfID, index))
        table.Rows.AddAt(index + 2, row)
    End Sub

so how do I do the opposite?  How can I check to even see if the CreateRow is even there.  It's a bit tricky and not sure how to attack this