使用 OleDbConnection 连接

我正在尝试连接到具有两个表的数据库。但是，当我尝试登录后，出现错误。该错误表明零点处没有行。我认为这是因为我的联系：

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

namespace Project3
{

public partial class _Default : System.Web.UI.Page
{

    protected void Page_Load(object sender, EventArgs e)
    {

    }

    protected void login_Click(object sender, EventArgs e)
    {
        OleDbConnection connect = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\\Users\\parodeghero\\Documents\\Visual Studio 2010\\Projects\\Project3\\Project3\\App_Data\\QA.mdb;Persist Security Info=True");
        //set up connection string
        OleDbCommand command = new OleDbCommand("select * from Employee where Login=@login", connect);
        OleDbParameter param0 = new OleDbParameter("@login", OleDbType.VarChar);

        param0.Value = employeeID.Text;
        command.Parameters.Add(param0);

        //middle tier to run connect
        OleDbDataAdapter da = new OleDbDataAdapter(command);

        DataSet dset = new DataSet();

        da.Fill(dset);

        //problem line
       if (dset.Tables[0].Rows[0]["Password"].ToString().Equals(password.Text))
        {

您需要打开连接

protected void login_Click(object sender, EventArgs e)
{
    string pathToYourFileMDB = @"C:\yourPathHere\File.mdb";
    
    try
    {
        OleDbConnection connect = new OleDbConnection($"Provider=Microsoft.Jet.OLEDB.4.0;Data Source={pathToYourFileMDB};Persist Security Info=True");
        
        //set up connection string
        OleDbCommand command = new OleDbCommand("select * from Employee where Login=@login", connect);
        OleDbParameter param0 = new OleDbParameter("@login", OleDbType.VarChar);

        param0.Value = employeeID.Text;
        command.Parameters.Add(param0);
        
        //open connection
        connect.Open();
        
        //middle tier to run connect
        OleDbDataAdapter da = new OleDbDataAdapter(command);
        DataSet dset = new DataSet();
        da.Fill(dset);
    }
    catch(Exception err)
    { 
        Debug.WriteLine(err.Message);
    }
}