Question

asp.net 关于关闭 DataReader 的问题

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.OleDb;

public partial class reg : System.Web.UI.Page
{

protected void Page_Load(object sender, EventArgs e)
{

}
protected void Button2_Click(object sender, EventArgs e)
{
name.Text = "";
password.Text = "";
password2.Text = "";
}
protected void Button1_Click(object sender, EventArgs e)
{
if(name.Text == "" || password.Text == "" || password2.Text =="" )
{
Response.Write("<script>alert('这里的信息都要填写！');history.go(-1)</script>");
}
else
{
string strConnection = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + Server.MapPath("~/App_Data/no1.mdb");
OleDbConnection myConn = new OleDbConnection(strConnection);
myConn.Open();
String sq = "select * from [user] where userid='" + name.Text + "'";
OleDbCommand cmd = new OleDbCommand(sq, myConn);
OleDbDataReader da = cmd.ExecuteReader();

if (da.Read())
{
Response.Write("<script>alert('用户已经存在');history.go(-1)</script>");
}
else if (password.Text != password2.Text)
{
Response.Write("<script>alert('两次密码不相同');history.go(-1)</script>");
}
else
{
String sq2 = "insert into [user] (userid,password) values ('" + name.Text + "','" + password.Text + "')";
cmd.CommandText = sq2;
cmd.ExecuteNonQuery();
Response.Write("<script>alert('注册成功');window.window.location.href='Default.aspx';</script>");
}
myConn.Close();
}
}
}
错误提示： System.InvalidOperationException: 已有打开的与此命令相关联的 DataReader，必须首先将它关闭。

行 51: String sq2 = "insert into [user] (userid,password) values ('" + name.Text + "','" + password.Text + "')";
行 52: cmd.CommandText = sq2;
行 53: cmd.ExecuteNonQuery();
行 54: Response.Write("<script>alert('注册成功');window.window.location.href='Default.aspx';</script>");
行 55: }
53行出错
请高手解答...

Answer 1

if (da.Read())
{
Response.Write("<script>alert('用户已经存在');history.go(-1)</script>");
}
else if (password.Text != password2.Text)
{
Response.Write("<script>alert('两次密码不相同');history.go(-1)</script>");
}
else
{
改成

if (da.Read())
{
myConn.Close();

Response.Write("<script>alert('用户已经存在');history.go(-1)</script>");
}
else if (password.Text != password2.Text)
{
myConn.Close();

Response.Write("<script>alert('两次密码不相同');history.go(-1)</script>");
}
else
{
myConn.Close();

Answer 2

第52和53行改为
OleDbCommand cmd2 = new OleDbCommand(sq2, myConn);
cmd2.ExecuteNonQuery();