为甚么下面代码在listview内显示不了数据库内容！各位大仙帮帮忙啊？

Question

        public Form1()
        {
            SqlCommand sqlCommand;
            SqlConnection sqlConnection;            string cn = "Server=ELVIS-PC;Initial Catalog=学生管理数据库; User ID=sa; Password=12345";
            sqlConnection=new   SqlConnection(cn); 
            string   sql= "select   *   from  学生表 "; 
            sqlCommand=new   SqlCommand(sql,sqlConnection);
             sqlConnection.Open();
           
            DataSet ds = new DataSet();
            SqlDataAdapter da = new SqlDataAdapter(sql, sqlConnection);
            SqlCommandBuilder cb = new SqlCommandBuilder(da);
            da.Fill(ds);
            try
            {
                         // ListViewItem[] l = new ListViewItem[ds.Tables[0].Rows.Count];
            ListViewItem l = null;
           
                foreach (DataRow row in ds.Tables[0].Rows)
                {
                    l = new ListViewItem(row["学号"].ToString());
                    l.SubItems.Add(row["姓名"].ToString());                    l.SubItems.Add(row["性别"].ToString());
                    l.SubItems.Add(row["年龄"].ToString());
                    l.SubItems.Add(row["系别"].ToString());
                    l.SubItems.Add(row["班级"].ToString());
                    listView1.Items.Add(l);                }
            }
            catch
            {
            }
        
           
           
           
           
           
            InitializeComponent();        }       
        
       
    }
}

Answer 1

把try去掉，这里没必要加
你catch里什么都没有，光try等于把错误都屏蔽了
估计是tostring报错了

Answer 2

把try，catch去掉了，结果：  错误：未将对象引用设置到对象的实例。 listView1.Items.Add(l);
那怎么改?

Answer 3

我试过了 private static DataTable Array2ConvertDataTable(string[] ColumnNames, string[,] array2)
        {
            DataTable dt = new DataTable();
            for (int i = 0; i < ColumnNames.Length; i++)
            {
                dt.Columns.Add(ColumnNames[i]);
            }            for (int i = 0; i < array2.GetLength(0); i++)
            {
                DataRow dr = dt.NewRow();
                for (int j = 0; j < ColumnNames.Length; j++)
                {
                    dr[j] = array2[i, j].ToString();
                }
                dt.Rows.Add(dr);
            }
            return dt;
        }
  private void button2_Click(object sender, EventArgs e)
        {
            string[,] array3D = {    
                                { "1", "数组转DataTable 1", "0"},    
                                { "2", "数组转DataTable 2", "1"},    
                                { "3", "数组转DataTable 3", "1"},    
                                { "4", "数组转DataTable 4", "2"},    
                                { "5", "数组转DataTable 5", "2"},    
                                { "6", "数组转DataTable 6", "5"},    
                                };
            DataTable dt = Array2ConvertDataTable(new string[] { "Column1", "Column2", "Column3" }, array3D);
            dataGridView1.DataSource = Array2ConvertDataTable(new string[] { "Column1", "Column2", "Column3" }, array3D);
            ListViewItem l = null;
            foreach (DataRow row in dt.Rows)
            {
                l = new ListViewItem(row[0].ToString());
                l.SubItems.Add(row["Column1"].ToString());                l.SubItems.Add(row["Column2"].ToString());                l.SubItems.Add(row["Column3"].ToString());
                listView1.Items.Add(l);
            }
        }至少可以显示第一列
那估计是你没读出数据？

Answer 4

看dataTable有没有数据啊？Count是不是为0，为0则没有数据，大于0就读取了

Answer 5

ADO.NET：以针对“server=ELVIS-PC...."执行命令文本"Select *from .."是不是说读取数据成功了

Answer 6

ADO.NET：以针对“server=ELVIS-PC...."执行命令文本"Select *from .."是不是说读取数据成功了

Answer 7

datatable有数据！读取数据成功了，估计还是tostring

Answer 8

这哪看得出啊。你之间看DataTable。Rows。Count的值

Answer 9

如果只是读，可以这样
 public Form1()
  {
  SqlCommand sqlCommand;
  SqlConnection sqlConnection;  string cn = "Server=ELVIS-PC;Initial Catalog=学生管理数据库; User ID=sa; Password=12345";
  sqlConnection=new SqlConnection(cn);  
  string sql= "select * from 学生表 ";  
  sqlCommand=new SqlCommand(sql,sqlConnection);
  sqlConnection.Open();
 SqlDataReader jr = sqlCommand.ExecuteReader();
              while (jr.Read() == true)
{
                  item = listView1.Items.Add(jr[0].ToString());
             
                  item.SubItems.Add(jr[1].ToString());
                  item.SubItems.Add(jr[2].ToString());
                  item.SubItems.Add(jr[3].ToString());
                 item.SubItems.Add(jr[4].ToString());
                 item.SubItems.Add(jr[5].ToString());
 }
              jr.Close();
              sqlConnection.Close();

Answer 10

数据已经加载到dataset上了，在如何显示到listview上？之前已经设好头行了。

Answer 11

还是用Datareader搞出来了！private void Form1_Load(object sender, EventArgs e)
        {
            SqlCommand sqlCommand;
            SqlConnection sqlConnection;            string cn = "Server=ELVIS-PC;Initial Catalog=学生管理数据库; User ID=sa; Password=12345";
            sqlConnection = new SqlConnection(cn);
            string sql = "select   *   from  学生表 ";
            sqlCommand = new SqlCommand(sql, sqlConnection);
            sqlConnection.Open();           SqlDataReader read;
            read=sqlCommand.ExecuteReader();
            if(!read.HasRows)
            {
                MessageBox.Show("没有查询到数据");
            }
            while(read.Read())
            
            {  ListViewItem lvi = new ListViewItem(read["学号"].ToString());
            
            lvi.SubItems.AddRange(new string[] { read["姓名"].ToString(), 
                read["性别"].ToString(),
                read["年龄"].ToString(),
                read["系别"].ToString(),
                read["班级"].ToString()});
            listView1.Items.Add(lvi);
                
            
            }
            read.Close();
            sqlConnection.Close();
                    ;