我想从表中读取所有数据(包含3行),并将所有数据添加到通用集合中.从集合我wana绑定到gridview.
下面显示的代码可以工作,但最后一行在gridview中显示3次.可以帮助我.一个初学者
protected void Page_Load(object sender,EventArgs e)
{
List<Student> listid = new List<Student>();
Student stud = new Student();
sqlConnection con = new sqlConnection("........");
string sql = "select * from StudentInfo";
con.Open();
sqlCommand cmd = new sqlCommand(sql,con);
sqlDataReader dr = cmd.ExecuteReader();
while (dr.Read())
{
stud.Studid = Convert.ToInt32(dr["StudId"]);
stud.StudName = dr["StudName"].ToString();
stud.StudentDept = dr["StudentDept"].ToString();
listid.Add(stud);
}
GridView1.DataSource = listid;
GridView1.DataBind();
}
public class Student
{
private int studid;
public int Studid
{
get { return studid; }
set { studid = value; }
}
private string studName;
public string StudName
{
get { return studName; }
set { studName = value; }
}
private string studentDept;
public string StudentDept
{
get { return studentDept; }
set { studentDept = value; }
}
输出如下：
解决方法
你需要在循环中实例化你的对象
否则,您将收集相同的数据
所以代码应该是
否则,您将收集相同的数据
所以代码应该是
protected void Page_Load(object sender,EventArgs e)
{
List<Student> listid = new List<Student>();
sqlConnection con = new sqlConnection("........");
string sql = "select * from StudentInfo";
con.Open();
sqlCommand cmd = new sqlCommand(sql,con);
sqlDataReader dr = cmd.ExecuteReader();
while (dr.Read())
{
Student stud = new Student();
stud.Studid = Convert.ToInt32(dr["StudId"]);
stud.StudName = dr["StudName"].ToString();
stud.StudentDept = dr["StudentDept"].ToString();
listid.Add(stud);
}
GridView1.DataSource = listid;
GridView1.DataBind();
}
此外,使用数据读取器或直接打开连接不是一个好习惯
你应该使用using语句.
using(sqlConnection con = new sqlConnection("connection string")) { con.Open(); using(sqlCommand cmd = new sqlCommand("SELECT * FROM SoMetable",connection)) { using (sqlDataReader reader = cmd.ExecuteReader()) { if (reader != null) { while (reader.Read()) { //do something } } } // reader closed and disposed up here } // command disposed here } //connection closed and disposed here
