control Excel.Application

            Excel.Application oXL = new Excel.Application();

            oXL.Visible = true;
            Excel._Workbook output_Xl=(Excel._Workbook)oXL.Workbooks.Open(@"f:\date.xls",
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value
                );
            Excel._Workbook input_Xl = (Excel._Workbook)oXL.Workbooks.Open(@"f:\test.xls",
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value                
                );
            Excel.Worksheet input_sheet = (Excel.Worksheet)input_Xl.ActiveSheet;
            Excel.Worksheet output_sheet = (Excel.Worksheet)output_Xl.Sheets[1];
            Excel.Range input_Rng = input_sheet.get_Range("B2", "C" + input_sheet.UsedRange.Rows.Count.ToString());
            Excel.Range output_Rng = output_sheet.get_Range("A2", Missing.Value);

            Excel.Range rng1 = input_sheet.get_Range("B2", Missing.Value);
            Excel.Range rng2 = input_sheet.get_Range("C2", Missing.Value);
            Excel.Range rng0 = input_sheet.get_Range("A2", Missing.Value);

            DateTime[,] edt = new DateTime[input_sheet.UsedRange.Rows.Count, 2];
            TimeSpan[] ts = new TimeSpan[input_sheet.UsedRange.Rows.Count];

            for (int i = 0; i < input_sheet.UsedRange.Rows.Count - 1; i++)
            {
                edt[i, 0] = ConvertExcelDateToDate(rng1.Value2.ToString());
                edt[i, 1] = ConvertExcelDateToDate(rng2.Value2.ToString());

                ts[i] = edt[i, 1] - edt[i, 0];

                float start_X = (float)(((edt[i, 0].Day - 1) * 30 + 50)/1.333);
                float start_Y = (float)((i * 18 + 27)/1.333);
                float end_X = (float)(((edt[i, 1].Day) * 30 + 50)/1.333);

                Excel.Shape line = output_sheet.Shapes.AddLine(start_X, start_Y, end_X, start_Y);// 1.333  侨既苞 inch券魂
                
                //line style
                //line.Line.BeginArrowheadStyle = Microsoft.Office.Core.MsoArrowheadStyle.msoArrowheadOval;
                //line.Line.EndArrowheadStyle = Microsoft.Office.Core.MsoArrowheadStyle.msoArrowheadOpen;
                //line.Line.DashStyle = Microsoft.Office.Core.MsoLineDashStyle.msoLineLongDash;
                line.Line.Weight = (float)1.5;
                
                output_Rng.Value2 = rng0.Value2;
                //
                Excel.Shape start_circle = output_sheet.Shapes.AddShape(Microsoft.Office.Core.MsoAutoShapeType.msoShapeOval, (float)(start_X-2/1.333), (float)(start_Y-1.6/1.333), (float)3, (float)3);
                Excel.Shape end_circle = output_sheet.Shapes.AddShape(Microsoft.Office.Core.MsoAutoShapeType.msoShapeOval, (float)(end_X-2/1.333), (float)(start_Y - 1.6 / 1.333), (float)3, (float)3);
               // circle.Fill.Visible = Microsoft.Office.Core.MsoTriState.msoFalse;
                
                //add top of line's Text
                Excel.Shape text = output_sheet.Shapes.AddTextbox(Microsoft.Office.Core.MsoTextOrientation.msoTextOrientationHorizontal,0,0,0,0);
                text.Line.Visible = Microsoft.Office.Core.MsoTriState.msoFalse;
                text.Fill.Visible = Microsoft.Office.Core.MsoTriState.msoFalse;
                text.TextFrame.Characters(Missing.Value, Missing.Value).Text = rng0.Value2.ToString();
                text.TextFrame.AutoSize = true;
                text.TextFrame.Characters(Missing.Value, Missing.Value).Font.Size = "7";

                text.Left = (float)(start_X + (end_X - start_X) / 2.0 - text.Width / 2.0);
                text.Top = (float)(start_Y - 10);

                //add arc 
                //Excel.Shape arc = DateSheet.Shapes.AddShape(Microsoft.Office.Core.MsoAutoShapeType.msoShapeArc, (float)20, (float)20, (float)20, (float)20);
                //arc.Flip(Microsoft.Office.Core.MsoFlipCmd.msoFlipHorizontal);
                //arc.Line.Style = Microsoft.Office.Core.MsoLineStyle.msoLineStyleMixed;
                

                //MessageBox.Show(ts[i].Days.ToString());
                
                rng1 = rng1.get_Range("A2", Missing.Value);
                rng2 = rng2.get_Range("A2", Missing.Value);
                rng0 = rng0.get_Range("A2", Missing.Value);
                output_Rng = output_Rng.get_Range("A2", Missing.Value);
            }
            //DateSheet.Shapes.SelectAll();

            
            output_sheet.SaveAs(@"f:\date2.xls",
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value,
                Missing.Value
                );
            oXL.Quit();