C#中Excel的导入和导出的几种基本方式

在上一篇（http://www.cnblogs.com/fengchengjushi/p/3369386.html）介绍过，Excel也是数据持久化的一种实现方式。在C#中。我们常常会与Excel文件打交到。那么今天就讲讲在C#程序中操作Excel的问题。这里主要是导入和导出。

在页面中常常会遇到点击按钮实现GridView等控件的展示信息的下载，那么在程序中是如何实现数据下载的呢？其实简单的办法就是将这组规整的数据以Excel的方式保存到本地文件系统。我姑且称这种方式为"程序的方式"吧。

下面看具体代码实现:

 /// <summary>
        /// 程序的方式 
        /// </summary>
        /// <param name="ctl"></param>
        /// <param name="fileName"></param>
        public static void ExportByApplication(System.Web.UI.Control ctl, string fileName)
        {
            string style = @"<style> .text { mso-number-format:@; } </script> ";

            HttpContext.Current.Response.Charset = "UTF-8";

            HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.Default;

            HttpContext.Current.Response.ContentType = "application/ms-excel";

            HttpContext.Current.Response.AppendHeader("Content-Disposition", "attachment;filename=" + "" + HttpUtility.UrlEncode(fileName, System.Text.Encoding.Default) + ".xls");

            ctl.Page.EnableViewState = false;

            System.IO.StringWriter tw = new System.IO.StringWriter();

            System.Web.UI.HtmlTextWriter hw = new System.Web.UI.HtmlTextWriter(tw);

            ctl.RenderControl(hw);

            HttpContext.Current.Response.Write(style);

            HttpContext.Current.Response.Write(tw.ToString());

            HttpContext.Current.Response.End();

        }

当我们把这个方法在Button点击按钮下调用的时候，我们运行页面会惊奇的发现，如下场景:

看到这里你是不是”惊呆了"也。呵呵，明明我的控件Gridview是放在了具有runat=server的form表单中的呀？其实你只需要重写VerifyRenderingInServerForm事件。代码如下:

 public override void VerifyRenderingInServerForm(Control control)
        {
            // Confirms that an HtmlForm control is rendered for
        }

这里介绍一种与到类似的解决办法，无需重写上面的事件，方法如下:

 /// <summary>
        /// 程序的方式
        /// </summary>
        /// <param name="page"></param>
        /// <param name="table"></param>
        /// <param name="FileName"></param>
        public static void ExportByApplication(System.Web.UI.Page page, System.Data.DataTable table, string FileName)//整个GRIDVIEW导出到EXCEL.xls
        {
            FileName = HttpUtility.UrlEncode(FileName, System.Text.Encoding.UTF8);//解决导出时文件名汉字显示乱码的问题

            HttpResponse resp;
            resp = page.Response;
            resp.ContentEncoding = System.Text.Encoding.GetEncoding("GB2312");
            resp.AppendHeader("Content-Disposition", "attachment;filename=" + FileName);
            string colHeaders = "", ls_item = "";

            //定义表对象与行对象，同时用DataSet对其值进行初始化
            System.Data.DataRow[] myRow = table.Select();//可以类似dt.Select("id>10")之形式达到数据筛选目的
            int i = 0;
            int cl = table.Columns.Count;

            //取得数据表各列标题，各标题之间以t分割，最后一个列标题后加回车符
            for (i = 0; i < cl; i++)
            {
                if (i == (cl - 1))//最后一列，加n
                {
                    colHeaders += table.Columns[i].Caption.ToString() + "
";
                }
                else
                {
                    colHeaders += table.Columns[i].Caption.ToString() + "	";
                }

            }
            resp.Write(colHeaders);
            //向HTTP输出流中写入取得的数据信息

            //逐行处理数据  
            foreach (DataRow row in myRow)
            {
                //当前行数据写入HTTP输出流，并且置空ls_item以便下行数据    
                for (i = 0; i < cl; i++)
                {
                    if (i == (cl - 1))//最后一列，加n
                    {
                        ls_item += row[i].ToString() + "
";
                    }
                    else
                    {
                        ls_item += row[i].ToString() + "	";
                    }

                }
                resp.Write(ls_item);
                ls_item = "";

            }
            resp.End();
        }

这两个种方式(当然类似的方法很多)都是通过写入HTTP 响应输出流的方式写入到本地文件系统。

我们知道Excel本来就是小型的数据库模型，我姑且称之为"Oledb"的方式，因此我们可以考虑通过数据访问的形式来实现上面的效果。首先要引入Microsoft.Office.Interop.Excel;

    /// <summary>
        /// Oledb的方式
        /// </summary>
        /// <param name="fileName">Excel文件名</param>
        /// <param name="table">要导出的DataTable</param>
        /// <param name="AddHeader">是否要增加表头</param>
        public static void ExporExportByOledbtExcel(string fileName, System.Data.DataTable table, bool AddHeader)
        {

            object missing = System.Reflection.Missing.Value;
            Microsoft.Office.Interop.Excel.Application app = new Microsoft.Office.Interop.Excel.Application();
            app.Application.Workbooks.Add(true);
            Microsoft.Office.Interop.Excel.Workbook book = (Microsoft.Office.Interop.Excel.Workbook)app.ActiveWorkbook;
            Microsoft.Office.Interop.Excel.Worksheet sheet = (Microsoft.Office.Interop.Excel.Worksheet)book.ActiveSheet;

            if (AddHeader)
                for (int i = 0; i < table.Columns.Count; i++)
                    sheet.Cells[1, i + 1] = table.Columns[i].ColumnName;

            for (int i = 0, ei = AddHeader ? 2 : 1; i < table.Rows.Count; i++, ei++)
                for (int j = 0; j < table.Columns.Count; j++)
                    sheet.Cells[ei, j + 1] = table.Rows[i][j];


            string path = fileName.Substring(0, fileName.LastIndexOf('\') + 1).Trim('\');
            if (!System.IO.Directory.Exists(path))
                System.IO.Directory.CreateDirectory(path);

            book.SaveCopyAs(fileName);
            //关闭文件
            book.Close(false, missing, missing);
            //退出excel
            app.Quit();
        }

以上是Excl的导出。

再来看Excel的导入

  /// <summary>
        /// 以Oledb的方式导入
        /// </summary>
        /// <param name="fileName">包含excel文件的完整路径</param>
        /// <param name="sheetName">工作表名</param>
        /// <returns></returns>
        public static System.Data.DataTable ImportByOledb(string fileName, string sheetName)
        {
            System.Data.DataTable dt = new System.Data.DataTable();

            using (OleDbConnection con = new OleDbConnection(@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + fileName + ";Extended Properties=Excel 8.0"))
            {
                OleDbCommand cmd = new OleDbCommand("select * from [" + sheetName + "$]", con);

                OleDbDataAdapter oda = new OleDbDataAdapter(cmd);

                oda.Fill(dt);
            }

            return dt;

        }

这里涉及到连接字符串问题，请看:

string strConn = @"Provider=Microsoft.Jet.OleDb.4.0;" + "data source=" + filePath + ";Extended Properties='Excel 8.0; HDR=Yes; IMEX=1'"; //此连接只能操作Excel2007之前(.xls)文件
string strCon = @"Provider=Microsoft.Ace.OleDb.12.0;" + "data source=" + fileName + ";Extended Properties='Excel 12.0; HDR=Yes; IMEX=1'"

对已不同的office版本，连接字符串也不同。

主意，当我们使用程序导出，然后通过Excel "Oledb"的方式导入的时候，会出现如下问题。且看:

这是程序导出时导致的非标准的excel文件的缘故，这个是程序导出的弊端。需要加以适当的处理。在导出的时候，这里由于时间原因，先介绍到这儿。

下面是我的ExcelOperation类:

   /// <summary>
    /// Excelde导入和导出
    /// </summary>
    public class ExcelOperation
    {
        #region 导出到Excel
        /// <summary>
        /// 程序的方式 
        /// </summary>
        /// <param name="ctl"></param>
        /// <param name="fileName"></param>
        public static void ExportByApplication(System.Web.UI.Control ctl, string fileName)
        {
            string style = @"<style> .text { mso-number-format:@; } </script> ";

            HttpContext.Current.Response.Charset = "UTF-8";

            HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.Default;

            HttpContext.Current.Response.ContentType = "application/ms-excel";

            HttpContext.Current.Response.AppendHeader("Content-Disposition", "attachment;filename=" + "" + HttpUtility.UrlEncode(fileName, System.Text.Encoding.Default) + ".xls");

            ctl.Page.EnableViewState = false;

            System.IO.StringWriter tw = new System.IO.StringWriter();

            System.Web.UI.HtmlTextWriter hw = new System.Web.UI.HtmlTextWriter(tw);

            ctl.RenderControl(hw);

            HttpContext.Current.Response.Write(style);

            HttpContext.Current.Response.Write(tw.ToString());

            HttpContext.Current.Response.End();

        }

        /// <summary>
        /// 程序的方式
        /// </summary>
        /// <param name="page"></param>
        /// <param name="table"></param>
        /// <param name="FileName"></param>
        public static void ExportByApplication(System.Web.UI.Page page, System.Data.DataTable table, string FileName)//整个GRIDVIEW导出到EXCEL.xls
        {
            FileName = HttpUtility.UrlEncode(FileName, System.Text.Encoding.UTF8);//解决导出时文件名汉字显示乱码的问题

            HttpResponse resp;
            resp = page.Response;
            resp.ContentEncoding = System.Text.Encoding.GetEncoding("GB2312");
            resp.AppendHeader("Content-Disposition", "attachment;filename=" + FileName);
            string colHeaders = "", ls_item = "";

            //定义表对象与行对象，同时用DataSet对其值进行初始化
            System.Data.DataRow[] myRow = table.Select();//可以类似dt.Select("id>10")之形式达到数据筛选目的
            int i = 0;
            int cl = table.Columns.Count;

            //取得数据表各列标题，各标题之间以t分割，最后一个列标题后加回车符
            for (i = 0; i < cl; i++)
            {
                if (i == (cl - 1))//最后一列，加n
                {
                    colHeaders += table.Columns[i].Caption.ToString() + "
";
                }
                else
                {
                    colHeaders += table.Columns[i].Caption.ToString() + "	";
                }

            }
            resp.Write(colHeaders);
            //向HTTP输出流中写入取得的数据信息

            //逐行处理数据  
            foreach (DataRow row in myRow)
            {
                //当前行数据写入HTTP输出流，并且置空ls_item以便下行数据    
                for (i = 0; i < cl; i++)
                {
                    if (i == (cl - 1))//最后一列，加n
                    {
                        ls_item += row[i].ToString() + "
";
                    }
                    else
                    {
                        ls_item += row[i].ToString() + "	";
                    }

                }
                resp.Write(ls_item);
                ls_item = "";

            }
            resp.End();
        }

        //////////////////////////////////鉴于程序的方是比较多我就介绍两个，其目的最终都是将数据集导出


        /// <summary>
        /// Oledb的方式
        /// </summary>
        /// <param name="fileName">Excel文件名</param>
        /// <param name="table">要导出的DataTable</param>
        /// <param name="AddHeader">是否要增加表头</param>
        public static void ExporExportByOledbtExcel(string fileName, System.Data.DataTable table, bool AddHeader)
        {

            object missing = System.Reflection.Missing.Value;
            Microsoft.Office.Interop.Excel.Application app = new Microsoft.Office.Interop.Excel.Application();
            app.Application.Workbooks.Add(true);
            Microsoft.Office.Interop.Excel.Workbook book = (Microsoft.Office.Interop.Excel.Workbook)app.ActiveWorkbook;
            Microsoft.Office.Interop.Excel.Worksheet sheet = (Microsoft.Office.Interop.Excel.Worksheet)book.ActiveSheet;

            if (AddHeader)
                for (int i = 0; i < table.Columns.Count; i++)
                    sheet.Cells[1, i + 1] = table.Columns[i].ColumnName;

            for (int i = 0, ei = AddHeader ? 2 : 1; i < table.Rows.Count; i++, ei++)
                for (int j = 0; j < table.Columns.Count; j++)
                    sheet.Cells[ei, j + 1] = table.Rows[i][j];


            string path = fileName.Substring(0, fileName.LastIndexOf('\') + 1).Trim('\');
            if (!System.IO.Directory.Exists(path))
                System.IO.Directory.CreateDirectory(path);

            book.SaveCopyAs(fileName);
            //关闭文件
            book.Close(false, missing, missing);
            //退出excel
            app.Quit();
        }

        #endregion


        #region 从Excel导入
        /// <summary>
        /// 以Oledb的方式导入
        /// </summary>
        /// <param name="fileName">包含excel文件的完整路径</param>
        /// <param name="sheetName">工作表名</param>
        /// <returns></returns>
        public static System.Data.DataTable ImportByOledb(string fileName, string sheetName)
        {
            System.Data.DataTable dt = new System.Data.DataTable();

            using (OleDbConnection con = new OleDbConnection(@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + fileName + ";Extended Properties=Excel 8.0"))
            {
                OleDbCommand cmd = new OleDbCommand("select * from [" + sheetName + "$]", con);

                OleDbDataAdapter oda = new OleDbDataAdapter(cmd);

                oda.Fill(dt);
            }

            return dt;

        }
        #endregion
    }

哈哈，时间有点晚了，菜鸟的我要睡觉了。准备明天悲哀的生活了。2012.10.16晚。