ASP.Net動的にExcelファイルを読み込む最も簡単な方法

注意:各ページは、FileUpload、Button 1、Label 1、GridViewコントロールをドラッグし、新しいUploadedExcelフォルダを作成します.
Default.aspx.csコード:

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.OleDb;
using System.IO;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace WebApplication2
{
  public partial class WebForm1 : System.Web.UI.Page
  {
    protected void Page_Load(object sender, EventArgs e)
    {
       delete();
    }

    protected void Button1_Click(object sender, EventArgs e)
    {
      OleDbConnection conn = new OleDbConnection();
      OleDbCommand cmd = new OleDbCommand();
      OleDbDataAdapter da = new OleDbDataAdapter();
      DataSet ds = new DataSet();
      string query = null;
      string connString = "";
      string strFileName = DateTime.Now.ToString("ddMMyyyy_HHmmss");
      //string strFileName = Path.GetFileNameWithoutExtension(FileUpload1.PostedFile.FileName);
      string strFileType = Path.GetExtension(FileUpload1.FileName).ToString().ToLower();
      if (strFileType == ".xls" || strFileType == ".xlsx")
      {
        FileUpload1.SaveAs(Server.MapPath("~/UploadedExcel/" + strFileName + strFileType));
      }
      else
      {
        return;
      }
      string strNewPath = Server.MapPath("~/UploadedExcel/" + strFileName + strFileType);
      if (strFileType.Trim() == ".xls")
      {
        connString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + strNewPath + ";Extended Properties=\"Excel 8.0;HDR=Yes;IMEX=2\"";
      }
      else if (strFileType.Trim() == ".xlsx")
      {
        connString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + strNewPath + ";Extended Properties=\"Excel 12.0;HDR=Yes;IMEX=2\"";
      }
      query = "SELECT * FROM [Sheet1$]";
      conn = new OleDbConnection(connString);
      if (conn.State == ConnectionState.Closed)
      {
        conn.Open();
      }
      try
      {
        cmd = new OleDbCommand(query, conn);
        da = new OleDbDataAdapter(cmd);
        ds = new DataSet();
        da.Fill(ds);
        GridView1.DataSource = ds.Tables[0];
        GridView1.DataBind();
        Label1.Text = "    ";
      }
      catch (Exception ex)
      {
        Label1.Text = "    ";
        Response.Write(ex);
      }
      finally
      {
        da.Dispose();
        conn.Close();
        conn.Dispose();
      }
    }
    //    
    private void delete()
    {
      DirectoryInfo di = new DirectoryInfo(Server.MapPath("/UploadedExcel/"));
      FileInfo[] fi = di.GetFiles("*." + "*");
      DateTime dtNow = DateTime.Now;
      foreach (FileInfo tmpfi in fi)
      {
        TimeSpan ts = dtNow.Subtract(tmpfi.LastWriteTime);
        if (ts.Milliseconds > 100)
        {
          tmpfi.Attributes = FileAttributes.Normal;
          tmpfi.Delete();
        }
      }
    }
  }
}

注意:FileUploadコントロールはファイルの絶対パス(IE 6以下を除く)を直接取得することはできません.サーバにアップロードしてからデータのロードを行い、削除するしかありません.