登入框连接数据库问题.望高手解决下.

[lpqss1]

本人用的是SqlClient方式连接sql 2000
程序能正确运行.但是不论密码与账户输入
对或错.都执行请输入正确的用户名和密码.
不知道为什么.已经弄了很久了,
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;

namespace sqlconnection
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

private void button1_Click(object sender, EventArgs e)
{
if (namatext.Text.Trim() == "" || pswtext.Text.Trim() == "")
MessageBox.Show("请输入用户名和密码", "提示");
else
{
string Afile = "server=LAIPAN-B0559C3A;uid=sa;pwd=123;database=user";
SqlConnection AconnStr = new SqlConnection(Afile);
AconnStr.Open();

string sql="select USER from UU where USER='"+ namatext.Text.Trim()+ "'and PSW='"+ pswtext.Text.Trim() +"'";
SqlCommand cmd=new SqlCommand(sql,AconnStr);

SqlDataReader myReader = null;
try
{
myReader = cmd.ExecuteReader();
}
catch (Exception ex)
{ if(ex!=null) Console.Write("执行错误");}
if(myReader.Read())
{
this.Visible=false;
Form2 form2=new Form2();
form2.Show();
}

else
{
MessageBox.Show("用户名或者密码错误", "警告");
namatext.Text = "";
pswtext.Text="";
namatext.Focus();
}
}
}

private void button2_Click(object sender, EventArgs e)
{
this.Close();
}


}
}

[TkingCN]

把调试点设在private void button1_Click(object sender, EventArgs e) 旁边
debug单步调试 → F11 观察你的pswtext.Text和namatext.Text的值

[TkingCN]

仔细看勒下你的代码 貌似格式有问题 你的 private void button1_Click(object sender, EventArgs e)
{
if (namatext.Text.Trim() == "" || pswtext.Text.Trim() == "")
MessageBox.Show("请输入用户名和密码", "提示"); 这个后面没有“{”


你的else前面为什么没有“}”

[TkingCN]

if (namatext.Text.Trim() == "" || pswtext.Text.Trim() == "")★
MessageBox.Show("请输入用户名和密码", "提示");
■else
{
string Afile = "server=LAIPAN-B0559C3A;uid=sa;pwd=123;database=user";
SqlConnection AconnStr = new SqlConnection(Afile);
AconnStr.Open();
(★位置)IF后面为什么没有“{”
(■位置)else前面为什么没有"}"

[lpqss1]

因为if语句后面只有一句话,不需要{}

[PandaIT]

using System; 
using System.Collections.Generic; 
using System.ComponentModel; 
using System.Data; 
using System.Drawing; 
using System.Text; 
using System.Windows.Forms; 
using System.Data.SqlClient; 

namespace sqlconnection 
{ 
    public partial class Form1 : Form 
    { 
        public Form1() 
        { 
            InitializeComponent(); 
        } 

        private void button1_Click(object sender, EventArgs e) 
        { 
            if (namatext.Text.Trim() == "" || pswtext.Text.Trim() == "") 
                MessageBox.Show("请输入用户名和密码", "提示"); 
        else 
        { 
            string Afile = "server=LAIPAN-B0559C3A;uid=sa;pwd=123;database=user"; 
            SqlConnection AconnStr = new SqlConnection(Afile); 
            AconnStr.Open(); 
            //你sql这里就有问题
            string sql="select count(*) from UU where USER='"+ namatext.Text.Trim()+ "'and PSW='"+ pswtext.Text.Trim() +"'"; 
            SqlCommand cmd=new SqlCommand(sql,AconnStr); 
            
            int count=0;
            count=(int)cmd.ExecuteScalar();//执行查询语句

            if(count==1){
			    MessageBox.Show("成功!")
				this.Visible=false; 
                Form2 form2=new Form2(); 
                form2.Show(); 
			}
			 else 
            { 
              MessageBox.Show("用户名或者密码错误", "警告"); 
              namatext.Text = ""; 
                pswtext.Text=""; 
                namatext.Focus(); 
            } 
            catch (Exception ex) 
            { 
				MessageBox.Show("出错!")
			} 
        } 
        } 

        private void button2_Click(object sender, EventArgs e) 
        { 
            this.Close(); 
        } 
    } 
}

[聖少俊]

先F9设置断点，F5运行，然后按F10一步一步来测试，就能发现问题了

[lpqss1]

数据库我看了很多次了,没问题啊,我也感觉奇怪了.连access都没问题的,我晕了

[lpqss1]

大家顶起来,太奇怪了,搞不懂

[caorenlong]

myReader = cmd.ExecuteReader();

你跟踪到这句,
如果用户密码正确,应该是1
错误,是 -1

[lpqss1]

算了,看来是没办法了.

[lpqss1]

还是一样,肯定就sql这个地方错的,但是怎么也找不出.
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;

namespace sqlconnection
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

private void button1_Click(object sender, EventArgs e)
{
if (namatext.Text.Trim() == "" || pswtext.Text.Trim() == "")
MessageBox.Show("请输入用户名和密码", "提示");
else
{
string Afile = "server=LAIPAN-B0559C3A;uid=sa;pwd=123;database=user";
SqlConnection AconnStr = new SqlConnection(Afile);
AconnStr.Open();

string sql = "select * from UU where USER='" + namatext.Text.Trim() + "'and PSW='" + pswtext.Text.Trim() + "'";
SqlCommand cmd = new SqlCommand(sql, AconnStr);

cmd.CommandText = sql;

if (null!=cmd.ExecuteReader())//如果这里的if语句里这样写的话,密码错误也能连上数据库.但如果这样写if(null!=ExecuteDScalar())不管密码对错都连 不上数据库
{
this.Visible = false;
Form2 form2 = new Form2();
form2.Show();
}

else
{
MessageBox.Show("用户名或者密码错误", "警告");
namatext.Text = "";
pswtext.Text = "";
namatext.Focus();
}
}
}

private void button2_Click(object sender, EventArgs e)
{
this.Close();
}


}
}

[lpqss1]

up

[这个还能被注册？]

数据库有问题吧？有这条记录没？

[yjvjom]

try
{
myReader = cmd.ExecuteReader(); //你要在此加入一个判断，如下
if (!reader.Read())
MessageBox.Show("用户名或者密码错误", "警告");
}
catch (Exception ex)
{
if(ex!=null) Console.Write("执行错误");}
if(myReader.Read()) //这个判断有问题，因为如果报错则myReader肯定是==null
{
this.Visible=false;
Form2 form2=new Form2();
form2.Show();
}
else
{
MessageBox.Show("用户名或者密码错误", "警告");
namatext.Text = "";
pswtext.Text="";
namatext.Focus();
}
}

但总的来看应该是你的数据联接字符串有问题（登录到SQL的密码错误或其他）

[lpqss1]

up

[IamHandsomeman]

楼主，好像数据库的数据表不给有这个名字的吧

user

你换一个数据表名字看看！

[马少华]

namatext,pwstext肯定是这两个控件关联的是别的控件。而不是你要检测的控件。

[h2325124]

有可能是你的SQL语句有问题,user在SQL中是关键字,你用中括号括起来试试
string sql="select [USER] from UU where USER='"+ namatext.Text.Trim()+ "'and PSW='"+ pswtext.Text.Trim() +"'";

[PandaIT]

 string sql="select count(*) from UU where USER='"+ namatext.Text.Trim()+ "'and PSW='"+ pswtext.Text.Trim() +"'"; 

//用占位符来

 string sql=string.Format("select count(*) from UU where USER='{0}' and PSW='{1}'",namatext.Text.Trim(),pswtext.Text.Trim()); 

[lpqss1]

谢谢你们的帮助,虽然问题没解决,但肯定是我自己的问题.可能是数据库建表的问题吧