.NET provides a very simple way to import, read and export .CSV files.

Now I will create an ASP.Net application where I will bind a grid with the imported .CSV file.

Then you can also export the displayed data in CSV file format.

Step 1

In Visual Studio 2013 first create a simple web application and add a web form just like “Default.aspx”.

default

Step 2

Add a folder like “upload” for storing the imported .CSV file.

Step 3

Prepare a .CSV file for import in the following format.

id

Step 4

Add the following controls to the Deafult.aspx file.

  1. <%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
  3. <!DOCTYPE html>
  5. <html xmlns="http://www.w3.org/1999/xhtml">
  6. <head runat="server">
  7. <title>Import/Export/Read CSV file</title>
  8. </head>
  9. <body>
  10. <form id="form1" runat="server">
  11. <div>
  12. <div id="dvforgeneratingexcel">
  13. <div>
  14. <asp:GridView ID="wdgList" runat="server" Height="410px" AutoGenerateColumns="False"
  15. Style="width: 99.8%;">
  16. <Columns>
  17. <asp:BoundField DataField="ID" HeaderText="ID"></asp:BoundField>
  18. <asp:BoundField DataField="Name" HeaderText="Name"></asp:BoundField>
  19. </Columns>
  21. </asp:GridView>
  22. </div>
  23. <div class="pull-right">
  24. <asp:Button runat="server" ID="btnExport" Text="Export" OnClick="btnExport_OnClick" />
  25. </div>
  26. </div>
  27. <div id="dvforexcelimport">
  28. <asp:FileUpload Width="300" ID="FileUpload1" CssClass="form-control" runat="server" />
  29. <asp:Button ID="btn_import" runat="server" CssClass="btn btn-default" Text="Upload Excel sheet" OnClick="btn_import_Click" />
  30. </div>
  32. </div>
  33. </form>
  34. </body>
  35. </html>
Step 5
  1. using System;
  2. using System.Collections.Generic;
  3. using System.Data;
  4. using System.Data.OleDb;
  5. using System.IO;
  6. using System.Linq;
  7. using System.Text;
  8. using System.Web;
  9. using System.Web.UI;
  10. using System.Web.UI.WebControls;
  12. public partial class _Default : System.Web.UI.Page
  13. {
  14. DataTable dt = new DataTable();
  15. DataTable CSVTable = new DataTable();
  16. protected void Page_Load(object sender, EventArgs e)
  17. {
  18. }
  19. /// <summary>
  20. /// Exporting of the .CSV file.
  21. /// </summary>
  22. /// <param name="sender"></param>
  23. /// <param name="e"></param>
  24. protected void btnExport_OnClick(object sender, EventArgs e)
  25. {
  26. try
  27. {
  28. Response.Clear();
  29. Response.ClearContent();
  30. StringBuilder sb = new StringBuilder();
  31. sb.AppendLine("ID,Name");
  32. Response.ContentType = "application/x-msexcel";
  34. Response.AddHeader("content-disposition", "attachment; filename=ManageList.csv");
  35. Response.Write(sb.ToString());
  36. if (ViewState["CSVTable"] != "")
  37. {
  38. dt = ViewState["CSVTable"] as DataTable;
  39. if ((dt != null) && (dt.Rows.Count > 0))
  40. {
  41. foreach (DataRow row in dt.Rows)
  42. {
  43. sb = new StringBuilder((string)row[0]);
  44. for (int i = 1; i < dt.Columns.Count; i++)
  45. {
  46. if (row[i] is DBNull)
  47. sb.Append(",NULL");
  48. else if (i == 2)
  49. sb.Append("," + new DateTime((long)row[i]).ToString("G"));
  50. else
  51. sb.Append("," + row[i].ToString());
  53. }
  54. sb.AppendLine();
  55. Response.Write(sb.ToString());
  56. }
  57. }
  58. }
  59. Response.Flush();
  60. Response.Close();
  61. Response.End();
  62. }
  63. catch (Exception ex) { }
  65. }
  66. /// <summary>
  67. /// Importing of .CSV file.
  68. /// </summary>
  69. /// <param name="sender"></param>
  70. /// <param name="e"></param>
  71. protected void btn_import_Click(object sender, EventArgs e)
  72. {
  73. try
  74. {
  75. if (FileUpload1.HasFile)
  76. {
  77. int flag = 0;
  78. string FileName = Path.GetFileName(FileUpload1.PostedFile.FileName);
  79. string RandomName = DateTime.Now.ToFileTime().ToString();
  80. string Extension = Path.GetExtension(FileUpload1.PostedFile.FileName);
  81. string FolderPath ="~/upload/";
  83. string FilePath = Server.MapPath(FolderPath + RandomName + FileName);
  85. string[] filenames = Directory.GetFiles(Server.MapPath("~/upload"));
  87. if (filenames.Length > 0)
  88. { foreach (string filename in filenames)
  89. {
  90. if (FilePath == filename)
  91. {
  93. flag = 1;
  94. break;
  95. }
  96. }
  98. if (flag == 0)
  99. {
  100. FileUpload1.SaveAs(FilePath);
  101. ReadCSVFile(FilePath);
  102. }
  104. }
  105. else
  106. {
  107. FileUpload1.SaveAs(FilePath);
  108. ReadCSVFile(FilePath);
  109. }
  110. }
  111. else
  112. {
  113. String msg = "Select a file then try to import";
  114. }
  115. }
  117. catch (Exception ex)
  118. {
  119. throw ex;
  120. }
  121. }
  122. /// <summary>
  123. /// Reading of the .CSV file.
  124. /// </summary>
  125. /// <param name="fileName"></param>
  126. public void ReadCSVFile(string fileName)
  127. {
  128. try {
  129. string connection = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source={0}\\;Extended Properties='Text;HDR=Yes;FMT=CSVDelimited'";
  131. connection = String.Format(connection, Path.GetDirectoryName(fileName));
  134. OleDbDataAdapter csvAdapter;
  135. csvAdapter = new OleDbDataAdapter("SELECT * FROM [" + Path.GetFileName(fileName) + "]", connection);
  137. if (File.Exists(fileName) && new FileInfo(fileName).Length > 0)
  138. {
  139. try
  140. { csvAdapter.Fill(CSVTable);
  141. if ((CSVTable != null) && (CSVTable.Rows.Count > 0))
  142. {
  143. ViewState["CSVTable"] = CSVTable;
  144. wdgList.DataSource = CSVTable;
  145. wdgList.DataBind();
  146. }
  147. else
  148. {
  149. String msg = "No records found";
  150. }
  151. }
  152. catch (Exception ex)
  153. {
  154. throw new Exception(String.Format("Error reading Table {0}.\n{1}", Path.GetFileName(fileName), ex.Message));
  155. }
  156. }
  157. }
  158. catch (Exception ex) { }
  159. }
  160. }
Thanks.