using System;
using System.Data;
using System.Data.OleDb;
using System.Collections.Generic;
using System.Linq;
using System.Text;


namespace DataSet
{
    class Program
    {
        static void Main(string[] args)
        {  // Creat conection object for Microsoft Access OLE DB Provider;
            //note @ sign prefacing string literal so backslashes in path name;
            //work
            OleDbConnection thisConnection = new OleDbConnection(
                @"provider=Microsoft.Jet.OLEDB.4.0;Data Source=G:\c#教程\协和医院.mdb");
            // Creat DataAdapter object
            OleDbDataAdapter thisAdapter = new OleDbDataAdapter(
                "SELECT ID, 字段1,字段2,字段3,字段4,字段5,字段6,字段7,字段8  FROM Sheet1", thisConnection);
            // Create DataSet to contain related data tables,rows and columns
            System.Data.DataSet thisDataSet = new System.Data.DataSet();
            //Fill DataSet using query defined previously for DataAdapter
            thisAdapter.Fill(thisDataSet, "Sheet1" );
            foreach (DataRow theRow in thisDataSet.Tables["Sheet1 "].Rows)
            {
                Console.WriteLine(theRow["ID"] + "\t" + theRow["字段1"] + "\t" +
                    theRow[" 字段2"] + "\t" + theRow["字段3"] + "\t" +
                    theRow["字段4"] + "\t" +
                    theRow[" 字段5"] + "\t" +
                    theRow[" 字段6"] + "\t" +
                    theRow[" 字段7"] + "\t" +
                    theRow[" 字段8"]);
            }
            thisConnection.Close();
            Console.Write("Program finished,press Enter /Return to continue:");
            Console.ReadLine();
        }

        }
    }



这句thisDataSet.Tables["Sheet1 "].Rows  未将对象引用设置到对象的实例，不知道怎么改，希望大家帮忙啊，谢谢

thisAdapter.Fill(thisDataSet, "Sheet1" );，这里面这个表的名称是"Sheet1"，
而thisDataSet.Tables["Sheet1 "]，表的名称后面多加了一个空格？
您把空格去掉一下，看一下是不是这个原因导致的。

支持ls
也就是没有这个表名.