关于C#读excel的例子，看不懂

关于C#读excel的例子，看不懂，请教高手
Excel.Application excel = null;
   Excel.Workbooks wbs = null;
   Excel.Workbook wb = null;
   Excel.Worksheet ws = null;
   Excel.Range range1 = null;
   object Nothing = System.Reflection.Missing.Value;
     
   try
   {
    excel = new Excel.Application();
    excel.UserControl = true;
    excel.DisplayAlerts = false;
                     
    excel.Application.Workbooks.Open(this.FilePath,Nothing,Nothing,Nothing,Nothing,Nothing,Nothing,Nothing,Nothing,Nothing,Nothing,Nothing,Nothing ) ;
     
    wbs = excel.Workbooks;
    wb = wbs[1];
    ws = (Excel.Worksheet)wb.Worksheets["Sheet2"];
     
          
    int rowCount = ws.UsedRange.Rows.Count;
    int colCount = ws.UsedRange.Columns.Count;
    if (rowCount <= 0)
     throw new InvalidFormatException("文件中没有数据记录");
    if (colCount < 4 ) 
     throw new InvalidFormatException("字段个数不对");
     
    for (int i = 0;i    {

     this.rowNo = i + 1;
     object[] row = new object[4];
     for (int j = 0;j<4;j++)
     {
      range1 = ws.get_Range(ws.Cells[i+2,j+1],ws.Cells[i+2,j+1]);
      row[j] = range1.Value;

      if (row[0] == null)
      {
       this.isNullRecord++;
       break;
      }
     }
                    
     if (this.isNullRecord > 0)
      continue;

     DataRow dataRow = this.readExcel(row);

     if (this.isNullRecord == 1)
      continue;
   
     if (this.verifyData(dataRow) == false)
      errFlag++;
   
     this.updateTableCurr(dataRow);
    }
     
   }
   finally
   {
    if (excel != null)
    {
     if (wbs != null)
     {
      if (wb != null)
      {
       if (ws != null)

       {
        if (range1 != null)
        {
         System.Runtime.InteropServices.Marshal.ReleaseComObject(range1);
         range1 = null;
        }
        System.Runtime.InteropServices.Marshal.ReleaseComObject(ws);
        ws = null;
       }
       wb.Close(false,Nothing,Nothing); 
       System.Runtime.InteropServices.Marshal.ReleaseComObject(wb);
       wb = null;
      }
      wbs.Close();
      System.Runtime.InteropServices.Marshal.ReleaseComObject(wbs);
      wbs = null;
     }
     excel.Application.Workbooks.Close();
     excel.Quit();
     System.Runtime.InteropServices.Marshal.ReleaseComObject(excel);
     excel = null;
     GC.Collect();
    }
   }
在网上看到一段代码，其中throw new InvalidFormatException("");
this.isNullRecord
(this.verifyData(dataRow) == false)
这几句什么意思 c# excel
[解决办法]
这是用InterOP操作Excel。
[解决办法]
你需要引入微软提供的关于excel的dll
[解决办法]
throw new InvalidFormatException  捕获错误记录并抛出
isNullRecord   空格数据的个数
verifyData  通过将指定的签名数据与为指定数据计算的签名进行比较来验证指定的签名数据。
[解决办法]