Dataset中的表的名字是什么呢??

Question

DataSet ds = new DataSet("dt");
        void loaddata()
        {
            SqlConnection cn = new SqlConnection(cnstr);
            if (cn.State == ConnectionState.Closed) cn.Open();
            string sel = "select invcode,invname,invspec,invunit from inventory";
            SqlCommand cmd = new SqlCommand(sel, cn);
            SqlDataReader dr = cmd.ExecuteReader();
            DataTable dt= new DataTable();
            dt.Columns.Add("a", typeof(string));
            dt.Columns.Add("b", typeof(string));        
            while (dr.Read())
            {
                DataRow r = dt.NewRow();
                r["a"] = dr[0].ToString();
                r["b"] = dr[1].ToString();
                dt.Rows.Add(r);
                Thread.Sleep(100);
            }
            cn.Dispose();
            ds.Tables.Add(dt);//把这个表加入Dataset中
        }
        void addlistviewData(ListView lv)
        {
            DataTable dx = new DataTable();
            dx=ds.Tables["名字是什么呢?"];            
            for (int i = 0; i < dx.Rows.Count; i++)
            {
                ListViewItem lvv = new ListViewItem(dx.Rows[i][0].ToString());
                lvv.SubItems.Add(dx.Rows[i][1].ToString());
                lv.Items.Insert(lv.Items.Count, lvv);
                //Thread.Sleep(5);
            }
        }

Answer 1

DataSet ds = new DataSet("dt");
你这是全局的么

Answer 2

dx=ds.Tables[0];
或者
dx=ds.Tables["dt"];

Answer 3

我发现下面的代码没有把表加入到Dataset中呢??DataSet ds = new DataSet("dt");
        void loaddata()
        {
            SqlConnection cn = new SqlConnection(cnstr);
            if (cn.State == ConnectionState.Closed) cn.Open();
            string sel = "select invcode,invname,invspec,invunit from inventory";
            SqlCommand cmd = new SqlCommand(sel, cn);
            SqlDataReader dr = cmd.ExecuteReader();
            DataTable dt= new DataTable();
            dt.Columns.Add("a", typeof(string));
            dt.Columns.Add("b", typeof(string));        
            while (dr.Read())
            {
                DataRow r = dt.NewRow();
                r["a"] = dr[0].ToString();
                r["b"] = dr[1].ToString();
                dt.Rows.Add(r);
                Thread.Sleep(100);
            }
            cn.Dispose();
            ds.Tables.Add(dt);//把这个表加入Dataset中
        }
我是用
ds.Tables.Count.ToString();
发现结果为0

Answer 4

DataSet ds = new DataSet();
        Thread th = null;
        void loaddata()
        {
            SqlConnection cn = new SqlConnection(cnstr);
            if (cn.State == ConnectionState.Closed) cn.Open();
            string sel = "select invcode,invname,invspec,invunit from inventory";
            SqlCommand cmd = new SqlCommand(sel, cn);
            SqlDataReader dr = cmd.ExecuteReader();
            DataTable dt = new DataTable("zjh");
            dt.Columns.Add("a", typeof(string));
            dt.Columns.Add("b", typeof(string));
            dt.PrimaryKey = new DataColumn[] { dt.Columns["a"] };            while (dr.Read())
            {
                DataRow r = dt.NewRow();
                r["a"] = dr[0].ToString();
                r["b"] = dr[1].ToString();
                dt.Rows.Add(r);
                Thread.Sleep(1);
            }
            cn.Dispose();
            ds.Tables.Add(dt);      
        }
        void addlistviewData(ListView lv)
        {
            DataTable dx = new DataTable();
            dx = ds.Tables["zjh"];   //这里Ds没有表,用ds.Tables.Count.ToString();  值为0
            for (int i = 0; i < dx.Rows.Count; i++)
            {
                ListViewItem lvv = new ListViewItem(dx.Rows[i][0].ToString());
                lvv.SubItems.Add(dx.Rows[i][1].ToString());
                lv.Items.Insert(lv.Items.Count, lvv);
            }
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            listView1.View = View.Details;
            listView1.FullRowSelect = true;
            listView1.GridLines = true;
            listView1.Columns.Add("aa", 100, HorizontalAlignment.Left);
            listView1.Columns.Add("aa", 100, HorizontalAlignment.Left);
            listView1.Columns.Add("aa", 100, HorizontalAlignment.Left);
            listView1.Columns.Add("aa", 100, HorizontalAlignment.Left);
        }
        private void button1_Click(object sender, EventArgs e)
        {         
            //为什么用线程就不能给变量DS(DataSet)加入表呢??
            th = new Thread(new ThreadStart(dosome));
            timer1.Enabled = false;
            textBox2.Text = "this is ok";            
            addlistviewData(listView1);
        }
        private void dosome()
        {
            this.Invoke(new Action(loaddata));
        }

Answer 5

首先看看数据有没有填到DataSet中.

Answer 6

DataSet ds = new DataSet("dt");
        void loaddata()
        {
            SqlConnection cn = new SqlConnection(cnstr);
            if (cn.State == ConnectionState.Closed) cn.Open();
            string sel = "select invcode,invname,invspec,invunit from inventory";
            SqlCommand cmd = new SqlCommand(sel, cn);
            SqlDataReader dr = cmd.ExecuteReader();
            DataTable dt= new DataTable();
            dt.Columns.Add("a", typeof(string));
            dt.Columns.Add("b", typeof(string));   
            DataRow r ;//放循环外面试试
     
            while (dr.Read())
            {
                r=dt.NewRow();
                r["a"] = dr[0].ToString();
                r["b"] = dr[1].ToString();
                dt.Rows.Add(r);
                Thread.Sleep(100);
            }
            cn.Dispose();
            ds.Tables.Add(dt);//把这个表加入Dataset中
        }

Answer 7

还是不行呢??
//为什么用线程就不能给变量DS(DataSet)加入表呢??
            //直接调用loaddata()后,再用addlistviewData(listView1);却是可以的

Answer 8

 Thread thread = new Thread(new ThreadStart()); 
 thread.Start();