Question

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 WindowsFormsApplication5
{
public partial class Form5 : Form
{

public Form5()
{
InitializeComponent();
}
SqlConnection conn;

private void Form5_Load(object sender, EventArgs e)
{
}
private void button1_Click(object sender, EventArgs e)
{
conn = new SqlConnection("server=.;database=db_15;uid=sa;pwd=");
SqlCommand cmd = new SqlCommand("select*from tb_command", conn);
SqlDataAdapter sda = new SqlDataAdater();
sda.SelectCommand = cmd;
DataSet ds = new DataSet();
sda.Fill(ds, "cs");
dataGridView1.DataSourse = ds.Tables[0];
}
}
}
请教各位大侠，上一段程序中，我已经调用了using System.Data.SqlClient;为什么 SqlDataAdapter sda = new SqlDataAdater();和SqlCommand两个地方都显示缺少using指令或程序集引用

Answer 1

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

就是引用了以上四个名称空间。
引用的这几个名称空间都是.NET框架中的基础类库，用于实现一些基本的类。