Excel 读取数据，日期读取

   最近应要求写了一段代码，读取excel数据。excel读取方法有两个，两个各有自己的优势，同时也有各自的缺点。

方法一：采用sqlCommand命令读取方法。

具体实现代码如：               

               //FilePath是路径
                string conn = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source='" + FilePath + ";Extended Properties =Excel 8.0;";
                //Sheet1 是表名
                string sql = "select * from [Sheet1$] where [Rows]=" + 5;
                OleDbCommand cmd = new OleDbCommand(sql, new OleDbConnection(conn));
                OleDbDataAdapter ad = new OleDbDataAdapter(cmd);
                DataSet ds = new DataSet();
                ad.Fill(ds);
                dt = ds.Tables[0];
                dataGridView1.DataSource = ds.Tables[0];

这个方法的最大优点就是像操作数据库一样，能快速地读取数据，将数据保存到列表中。但是正因为跟数据库相似，所以excel数据的格式要统一，不能有标题什么的。因为我做的过程中所读的表固定前五行固定是标题，所以一直报错：在第33行格式不符，气死我了…………。

第二种方式是最传统的excel操作方式：

1，在引用部分添加引用：在com组建部分添加Microsoft Office12.0 object library 和Microsoft Excel 12.0 object library 两个库。

    在文件标头添加

    using Microsoft.Office.Core;
    using Excel;

然后读取的代码是：

  Excel.ApplicationClass app = new ApplicationClass();
            Excel.Application excel = null;
            Excel.Workbooks wbs = null;
            Excel.Workbook wb = null;
            Excel.Worksheet ws = null;
            Excel.Range rang1 = null;
            object Nothing = System.Reflection.Missing.Value;

            excel = new Excel.Application();

            try
            {

                FilePath是路径
                //string conn = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source='" + FilePath + ";Extended Properties =Excel 8.0;";
                Sheet1 是表名
                //string sql = "select * from [Sheet1$] where [Rows]=" + 5;
                //OleDbCommand cmd = new OleDbCommand(sql, new OleDbConnection(conn));
                //OleDbDataAdapter ad = new OleDbDataAdapter(cmd);
                //DataSet ds = new DataSet();
                //ad.Fill(ds);
                //dt = ds.Tables[0];
                //dataGridView1.DataSource = ds.Tables[0];

                excel.UserControl = true;
                excel.DisplayAlerts = false;
                excel.Application.Workbooks.Open(FilePath, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing);
                wbs = excel.Workbooks;
                wb = wbs[1];
                ws = (Excel.Worksheet)wb.Worksheets["Sheet1"];
                int rowCount = ws.UsedRange.Rows.Count;
              
                if (rowCount <= 5)
                {
                    DataCount = 0;
                    return;
                }
                else
                {
                    DataCount = rowCount - 5;
                    for (int i = 5; i <= rowCount; i++)
                    {
                        DataRow row1 = dt.NewRow();
                        rang1 = ws.get_Range(ws.Cells[i, 1], ws.Cells[i, 1]);
                        row1[0] = rang1.Value2;

                        row1[0] = app.WorksheetFunction.Text(rang1.Value2, "yyyy-mm-dd hh:mm:ss");
                        for (int j = 2; j <= 11; j++)
                        {
                            rang1 = ws.get_Range(ws.Cells[i, j], ws.Cells[i, j]);
                            row1[j - 1] = rang1.Value2;
                            //ReadStatus = (i-5)/DataCount ;
                            //SetMyGBar(ReadStatus);
                        }
                        dt.Rows.Add(row1);
                       
                    }
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
                return;
            }
            finally
            {
                if (excel != null)
                {
                    if (wbs != null)
                    {
                        if (wb != null)
                        {
                            if (ws != null) ;
                            {
                                if (rang1 != null)
                                {
                                    System.Runtime.InteropServices.Marshal.ReleaseComObject(rang1);
                                    rang1 = 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);
                    GC.Collect();
                    Read = true;
                }
            }

这个方法是逐行读取，好的地方就在于excel读取方式灵活，不想sqlcommand那么死板，可是最大的痛苦就是一个文件它要消化好久才能全部读取，花费的时间太大，还好我所做的时间可以久点，不知道你们有什么更好的方法，方便的话说出来给我参考参考。

在第二种方法中：我读取的数据中有日期时间，读取出来是39000.00000什么的，试过了很多种C#转换，依然无法如愿，最后考虑到这个事excel的函数，excel那么多函数，那么我们就从excel类中入手。

Excel.ApplicationClass app = new ApplicationClass();//初始化excel函数类。

row1[0] = app.WorksheetFunction.Text(rang1.Value2, "yyyy-mm-dd hh:mm:ss");//将那个数据转换为1990-1-1 12：30：12 ，呵呵……最后就读取excel的数据就ok了。看来简简单单的几句话，再加上zedgraph图像的X显示为事件数据，整整花了我两天的时间。至于zedgraph的内容，稍后更新。这是我第一篇技术文章。请各位博友给我一点点支持，谢谢……