C#中Excel的導入和導出的幾種基本方式

在上一篇（http://www.cnblogs.com/fengchengjushi/p/3369386.html）介紹過，Excel也是數據持久化的一種實現方式。在C#中。我們常常會與Excel文件打交到。那么今天就講講在C#程序中操作Excel的問題。這里主要是導入和導出。

在頁面中常常會遇到點擊按鈕實現GridView等控件的展示信息的下載，那么在程序中是如何實現數據下載的呢？其實簡單的辦法就是將這組規整的數據以Excel的方式保存到本地文件系統。我姑且稱這種方式為"程序的方式"吧。

下面看具體代碼實現:

 /// <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();

        }

當我們把這個方法在Button點擊按鈕下調用的時候，我們運行頁面會驚奇的發現，如下場景:

看到這里你是不是”驚呆了"也。呵呵，明明我的控件Gridview是放在了具有runat=server的form表單中的呀？其實你只需要重寫VerifyRenderingInServerForm事件。代碼如下:

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

這里介紹一種與到類似的解決辦法，無需重寫上面的事件，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)//整個GRIDVIEW導出到EXCEL.xls
        {
            FileName = HttpUtility.UrlEncode(FileName, System.Text.Encoding.UTF8);//解決導出時文件名漢字顯示亂碼的問題

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

            //定義表對象與行對象，同時用DataSet對其值進行初始化
            System.Data.DataRow[] myRow = table.Select();//可以類似dt.Select("id>10")之形式達到數據篩選目的
            int i = 0;
            int cl = table.Columns.Count;

            //取得數據表各列標題，各標題之間以t分割，最后一個列標題后加回車符
            for (i = 0; i < cl; i++)
            {
                if (i == (cl - 1))//最后一列，加n
                {
                    colHeaders += table.Columns[i].Caption.ToString() + "\n";
                }
                else
                {
                    colHeaders += table.Columns[i].Caption.ToString() + "\t";
                }

            }
            resp.Write(colHeaders);
            //向HTTP輸出流中寫入取得的數據信息

            //逐行處理數據  
            foreach (DataRow row in myRow)
            {
                //當前行數據寫入HTTP輸出流，並且置空ls_item以便下行數據    
                for (i = 0; i < cl; i++)
                {
                    if (i == (cl - 1))//最后一列，加n
                    {
                        ls_item += row[i].ToString() + "\n";
                    }
                    else
                    {
                        ls_item += row[i].ToString() + "\t";
                    }

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

            }
            resp.End();
        }

這兩個種方式(當然類似的方法很多)都是通過寫入HTTP 響應輸出流的方式寫入到本地文件系統。

我們知道Excel本來就是小型的數據庫模型，我姑且稱之為"Oledb"的方式，因此我們可以考慮通過數據訪問的形式來實現上面的效果。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">要導出的DataTable</param>
        /// <param name="AddHeader">是否要增加表頭</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);
            //關閉文件
            book.Close(false, missing, missing);
            //退出excel
            app.Quit();
        }

以上是Excl的導出。

再來看Excel的導入

  /// <summary>
        /// 以Oledb的方式導入
        /// </summary>
        /// <param name="fileName">包含excel文件的完整路徑</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;

        }

這里涉及到連接字符串問題，請看:

string strConn = @"Provider=Microsoft.Jet.OleDb.4.0;" + "data source=" + filePath + ";Extended Properties='Excel 8.0; HDR=Yes; IMEX=1'"; //此連接只能操作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'"

對已不同的office版本，連接字符串也不同。

主意，當我們使用程序導出，然后通過Excel "Oledb"的方式導入的時候，會出現如下問題。且看:

這是程序導出時導致的非標准的excel文件的緣故，這個是程序導出的弊端。需要加以適當的處理。在導出的時候，這里由於時間原因，先介紹到這兒。

下面是我的ExcelOperation類:

   /// <summary>
    /// Excelde導入和導出
    /// </summary>
    public class ExcelOperation
    {
        #region 導出到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)//整個GRIDVIEW導出到EXCEL.xls
        {
            FileName = HttpUtility.UrlEncode(FileName, System.Text.Encoding.UTF8);//解決導出時文件名漢字顯示亂碼的問題

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

            //定義表對象與行對象，同時用DataSet對其值進行初始化
            System.Data.DataRow[] myRow = table.Select();//可以類似dt.Select("id>10")之形式達到數據篩選目的
            int i = 0;
            int cl = table.Columns.Count;

            //取得數據表各列標題，各標題之間以t分割，最后一個列標題后加回車符
            for (i = 0; i < cl; i++)
            {
                if (i == (cl - 1))//最后一列，加n
                {
                    colHeaders += table.Columns[i].Caption.ToString() + "\n";
                }
                else
                {
                    colHeaders += table.Columns[i].Caption.ToString() + "\t";
                }

            }
            resp.Write(colHeaders);
            //向HTTP輸出流中寫入取得的數據信息

            //逐行處理數據  
            foreach (DataRow row in myRow)
            {
                //當前行數據寫入HTTP輸出流，並且置空ls_item以便下行數據    
                for (i = 0; i < cl; i++)
                {
                    if (i == (cl - 1))//最后一列，加n
                    {
                        ls_item += row[i].ToString() + "\n";
                    }
                    else
                    {
                        ls_item += row[i].ToString() + "\t";
                    }

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

            }
            resp.End();
        }

        //////////////////////////////////鑒於程序的方是比較多我就介紹兩個，其目的最終都是將數據集導出


        /// <summary>
        /// Oledb的方式
        /// </summary>
        /// <param name="fileName">Excel文件名</param>
        /// <param name="table">要導出的DataTable</param>
        /// <param name="AddHeader">是否要增加表頭</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);
            //關閉文件
            book.Close(false, missing, missing);
            //退出excel
            app.Quit();
        }

        #endregion


        #region 從Excel導入
        /// <summary>
        /// 以Oledb的方式導入
        /// </summary>
        /// <param name="fileName">包含excel文件的完整路徑</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，時間有點晚了，菜鳥的我要睡覺了。准備明天悲哀的生活了。2012.10.16晚。