How to possible to find out the number of rows painted in the WinForms TabControlAdv?

public int GetNumOfRows()
{
    float minHeight = 0, currentLineHeight = 0, maxHeight = 0;
    int rows = 1;
    SizeF preferedTabSize = SizeF.Empty;
    SizeF overlappedSize = SizeF.Empty;
    Graphics g = this.CreateGraphics();
    SizeF prefSize = new SizeF(this.ClientRectangle.Width, this.ClientRectangle.Height);
overlappedSize = TabRendererFactory.GetRegisteredExtender
(this.m_tabPanelRenderer.TabPanelData.TabStyle).GetOverlapSize(this.m_tabPanelRenderer.TabPanelData.TabSize);
    overlappedSize.Height += this.m_tabPanelRenderer.TabPanelData.AdjustTopGap;
    float usedUpLineWidth = overlappedSize.Width;
    float availableWidth = prefSize.Width;
    int i=0;
    foreach (ITabRenderer render in this.m_tabPanelRenderer.Renderers)
    {
       preferedTabSize = ((ITabRenderer)this.m_tabPanelRenderer.Renderers[i]).GetPreferredSize(g);
       if (preferedTabSize.Width + usedUpLineWidth <= availableWidth || usedUpLineWidth <= overlappedSize.Width)
       {
           // enough space available in current line
           usedUpLineWidth += preferedTabSize.Width;
       }
       else
       {
           // move to next line
           minHeight += currentLineHeight;
           rows++;
           // This item becomes the first item in the new line
           usedUpLineWidth = overlappedSize.Width + preferedTabSize.Width;
           if (maxHeight < currentLineHeight)
              maxHeight = currentLineHeight;
              currentLineHeight = 0F;
        }
        if (currentLineHeight < preferedTabSize.Height)
           currentLineHeight = preferedTabSize.Height;
           i++;
    }
    return rows;
}
public bool ShouldDrawVisible(ITabData tdata)
{
    return (tdata.TabVisible);
}

Public Function GetNumOfRows() As Integer
    Dim minHeight As Single = 0, currentLineHeight As Single = 0, maxHeight As Single = 0
    Dim rows As Integer = 1
    Dim preferedTabSize As SizeF = SizeF.Empty
    Dim overlappedSize As SizeF = SizeF.Empty
    Dim g As Graphics = Me.CreateGraphics()
    Dim prefSize As SizeF = New SizeF(Me.ClientRectangle.Width, Me.ClientRectangle.Height)
    overlappedSize = TabRendererFactory.GetRegisteredExtender (Me.m_tabPanelRenderer.TabPanelData.TabStyle).GetOverlapSize(Me.m_tabPanelRenderer.TabPanelData.TabSize)
    overlappedSize.Height += Me.m_tabPanelRenderer.TabPanelData.AdjustTopGap
    Dim usedUpLineWidth As Single = overlappedSize.Width
    Dim availableWidth As Single = prefSize.Width
    Dim i As Integer=0
    For Each render As ITabRenderer In Me.m_tabPanelRenderer.Renderers
       preferedTabSize = (CType(Me.m_tabPanelRenderer.Renderers(i), ITabRenderer)).GetPreferredSize(g)
      If preferedTabSize.Width + usedUpLineWidth <= availableWidth OrElse usedUpLineWidth <= overlappedSize.Width
        Then
         '' enough space available in current line
        usedUpLineWidth += preferedTabSize.Width
      Else
        '' move to next line
        minHeight += currentLineHeight
        rows += 1
        '' This item becomes the first item in the new line
        usedUpLineWidth = overlappedSize.Width + preferedTabSize.Width
        If maxHeight < currentLineHeight Then
           maxHeight = currentLineHeight
        End If
        currentLineHeight = 0F
      End If
     If currentLineHeight < preferedTabSize.Height Then
        currentLineHeight = preferedTabSize.Height
     End If
     i += 1
     Next render
   Return rows
End Function
Public Function ShouldDrawVisible(ByVal tdata As ITabData) As Boolean
   Return (tdata.TabVisible)
End Function