问C#表单中的SQL搜索

EN

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;

namespace USER_Lookup
{
    public partial class Search : Form
    {
        DataSet ds = new DataSet();
        SqlConnection cs = new SqlConnection("Data Source=PC01; Initial Catalog=DB01; Integrated Security=TRUE");
        SqlDataAdapter da = new SqlDataAdapter();

        public Search()
        {
            InitializeComponent();
                    }

        private void button_Search_Click(object sender, EventArgs e)
        {
            string badgeCode = textBox_badgeCode.Text.Trim();
            da.SelectCommand = new SqlCommand
                ("SELECT db01.dbo.staff.lastname AS 'Last Name', db01.dbo.staff.firstname AS 'First Name', db01.dbo.staff.badgecode AS 'User ID', db01.dbo.staffrole.name AS 'Role' FROM db01.dbo.staff, db01.dbo.staffrole, db01.dbo.staff_staffrole WHERE db01.dbo.staff.badgecode =" + badgeCode + "AND db01.dbo.staff.id = db01.dbo.staff_staffrole.staff_id AND db01.dbo.staff_staffrole.staffrole_id = db01.dbo.staffrole.id", cs);
            ds.Clear();
            da.Fill(ds);

            dg.DataSource = ds.Tables[0];
        }
    }
}