C# Excel表格读取，数据表为空

string strConn;
            strConn = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + fileDialog.FileName + ";Extended Properties='Excel 8.0;HDR=False;IMEX=1'";
            OleDbConnection Oleconn = new OleDbConnection(strConn);
            string strExcel = "";
            OleDbDataAdapter excelCommand = null;
            DataSet excel_ds = new DataSet();
            strExcel = "select * from [sheet1$]";
            try
            {
                Oleconn.Open();
                excelCommand = new OleDbDataAdapter(strExcel, Oleconn);
                excelCommand.Fill(excel_ds, "sheet1");//得到dataset
            }
            catch (System.Exception ex)
            {
                MessageBox.Show("导入出错：" + ex, "错误信息");
            }

这是我写的一个读取Excel表格然后我做数据读取的时候，读取的表格为空。。大家帮我看看我是不是我写的读取语句有问题

补充：                DataSet _DS = new DataSet();
                if (_DS.Tables["sheet1$"] != null)
                {
                    int RowCount = _DS.Tables["sheet1$"].Rows.Count;
                    int ColumnCount = _DS.Tables["sheet1$"].Columns.Count;
                    textBox1.Text = _DS.Tables["sheet1$"].Rows[2][2].ToString();

                    //循环每一行
                    for (int i = 0; i < RowCount; i++)
                    {
                        string itemName = _DS.Tables["sheet1$"].Rows[i][0].ToString();
                        ListViewItem item = new ListViewItem(itemName, i);

                        //循环每一列
                        for (int j = 1; j < ColumnCount; j++)
                        {
                            item.SubItems.Add(_DS.Tables["sheet1$"].Rows[i][j].ToString());
                        }
                        bool IsChecked = false;
                        //根据数据表中的flag字段来表识该行是否被选中
                        string _Flag = _DS.Tables["sheet1$"].Rows[i][3].ToString();
                        if (_Flag.Equals("0"))
                        {
                            IsChecked = false;
                        }
                        else
                        {
                            IsChecked = true;
                        }
                        item.Checked = IsChecked;
                        //将整理好的item加入到listview
                        listView1.Items.Add(item);
                        Oleconn.Close();
                        Oleconn.Dispose();
                    }

                }
                else
                {
                    MessageBox.Show("表格为空");
                }
        }

追问：是的。我可能没说清。后面写绑定数据到listview 空间的时候。读取表格为空。没有数据显示