GroupShape groupShape = presentation.Slides[0].Shapes[0] as GroupShape;
presentation.Slides[0].Ungroup(groupShape);

Placeholder placeholder = presentation.Slides[1].Shapes[0].Placeholder;
IShape[] shapes = presentation.Slides[1].GetPlaceholderShapes(placeholder);
for (int i = 0; i < shapes.Length; i++)
{
        if (shapes[i] is IAutoShape)
        {
            IAutoShape autoShape = shapes[i] as IAutoShape;
            if (autoShape.TextFrame != null)
            {
                Console.WriteLine(autoShape.TextFrame.Text);
            }
        }
} 

ArrayList groupShapeList = new ArrayList();
groupShapeList.Add(shape1);
groupShapeList.Add(shape2);
groupShapeList.Add(shape3);
GroupShape groupshape = ppt.Slides[0].GroupShapes(groupShapeList);

pt.PivotFields["OnHand"].RepeatItemLabels = true;

int width = 399;
int height = 159;
BarcodeSettings bs = new BarcodeSettings();
bs.Type = BarCodeType.UPCA;
bs.Unit = GraphicsUnit.Pixel;
bs.WideNarrowRatio = 0.5f;            
bs.TextFont = new Font("Arial", 20, FontStyle.Regular);            
string data = "602318275035";
bs.Data2D = data;
bs.Data = data;
bs.ShowTextOnBottom = true;            
bs.TopText = data;
bs.ShowTopText = true;
bs.TextAlignment = StringAlignment.Center;
bs.TopTextAligment = StringAlignment.Center;
bs.TopTextFont = new Font("Arial", 20, FontStyle.Regular);            
bs.AutoResize = false;            
bs.X = 3.0f;            
bs.BarHeight = height * 0.6f;            
bs.ImageWidth = width;
bs.ImageHeight = height;            
BarCodeGenerator generator = new BarCodeGenerator(bs);
Image barImage = generator.GenerateImage();            
barImage.Save(outputFile_img, ImageFormat.Png);

BarcodeSettings barsetting = new BarcodeSettings();
barsetting.Type=BarCodeType.EAN13;
barsetting.BackColor = Color.WhiteSmoke;
String data = "6901234567892";
barsetting.Data=data;
barsetting.Data2D=data;barsetting.TopText="EAN13";
barsetting.TopTextFont=new Font("Arial", 20, FontStyle.Regular);
barsetting.TopTextColor=Color.Red;
barsetting.ShowTopText=true;
barsetting.ShowTextOnBottom=true;
barsetting.TopTextAligment=StringAlignment.Center;
barsetting.BottomText="EAN";
barsetting.BottomTextFont=new Font("fangsong", 25, FontStyle.Bold);
barsetting.BottomTextColor=Color.Black;
barsetting.ShowBottomText=true;
barsetting.BottomTextAligment=StringAlignment.Far;
BarCodeGenerator generator = new BarCodeGenerator(barsetting);
Image barcode = generator.GenerateImage(); 
barcode.Save(outputFile_img);