异常:System.InvalidOperationException试图验证登录信息 [英] Exception: System.InvalidOperationException Trying to validate a login information
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问题描述
我正在尝试创建一个登录表单.但是数据库有问题.我创建了一个Windows窗体，其中包含用户名和密码以及一个登录按钮.但是我认为声明:
I am trying to create a login Form. But Having Problems with database. I have created a windows form which consists of a user name and password, and a login button. But I think statement :
DataAdapterObject.Fill(DataTableObject)
有一些错误.我正在使用Visual Studio Profesional 2013 Update 4和Sql Server 2014 Enterprise Editon.
has some error. I am using Visual Studio Profesional 2013 Update 4 and Sql Server 2014 Enterprise Editon.
代码如下:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace Society_Accounting_Software
{
public partial class LoginScreen : Form
{
SqlConnection databaseConnect = new SqlConnection();
public LoginScreen()
{
SqlConnection databaseConnect = new SqlConnection();
databaseConnect.ConnectionString = "Data Source=GAURAV-PC;Initial Catalog=SocietyAccountingDatabase;Integrated Security=True";
InitializeComponent();
}
private void label1_Click(object sender, EventArgs e)
{
}
private void Form1_Load(object sender, EventArgs e)
{
SqlConnection databaseConnect = new SqlConnection("Data Source=GAURAV-PC;Initial Catalog=SocietyAccountingDatabase;Integrated Security=True");
databaseConnect.Open();
}
private void textBox1_TextChanged(object sender, EventArgs e)
{
}
private void label2_Click(object sender, EventArgs e)
{
}
private void textBox1_TextChanged_1(object sender, EventArgs e)
{
}
private void button1_Click(object sender, EventArgs e)
{
string queryString = "select UserId,UserPassword from UserAccounts where UserId='gaurav' AND UserPassword='test123'";
SqlConnection databaseConnect = new SqlConnection();
databaseConnect.ConnectionString = "Data Source=GAURAV-PC;Initial Catalog=SocietyAccountingDatabase;Integrated Security=True";
databaseConnect.Open();
string userName = UserNameTextBox.Text;
string Password = PasswordTextBox.Text;
SqlCommand SqlCommandObject = new SqlCommand("select UserId,UserPassword from UserAccounts where UserId='"+userName+"' AND UserPassword='"+Password+"'");
SqlDataAdapter DataAdapterObject = new SqlDataAdapter(SqlCommandObject);
DataTable DataTableObject = new DataTable();
DataAdapterObject.Fill(DataTableObject);
if (DataTableObject.Rows.Count > 0)
{
MessageBox.Show("Login Sucessful");
AdminConsoleForm AdminConsole= new AdminConsoleForm();
this.Hide();
AdminConsole.Show();
}
else
{
MessageBox.Show("Invalid Login Name And Password Please Try Again!");
}
databaseConnect.Close();
//AdminConsoleForm AdminConsole= new AdminConsoleForm();
//this.Hide();
//AdminConsole.Show();
}
}
}
有人可以帮忙吗?
推荐答案
登录表单的简单代码:
namespace Society_Accounting_Software
{
public partial class LoginScreen : Form
{
SqlConnection databaseConnect = new SqlConnection();
public LoginScreen()
{
SqlConnection databaseConnect = new SqlConnection();
databaseConnect.ConnectionString = "Data Source=GAURAV-PC;Initial Catalog=SocietyAccountingDatabase;Integrated Security=True";
InitializeComponent();
}
private void label1_Click(object sender, EventArgs e)
{
}
private void Form1_Load(object sender, EventArgs e)
{
}
private void textBox1_TextChanged(object sender, EventArgs e)
{
}
private void label2_Click(object sender, EventArgs e)
{
}
private void textBox1_TextChanged_1(object sender, EventArgs e)
{
}
private void button1_Click(object sender, EventArgs e)
{
try
{
if (!(UserNameTextBox.Text == string.Empty))
{
if (!(PasswordTextBox.Text== string.Empty))
{
//this represent your connection to database
String str = "Data Source=GAURAV-PC;Initial Catalog=SocietyAccountingDatabase;Integrated Security=True";
String query = "select * from UserAccounts where userid = '"+UserNameTextBox.Text+"'and password = '"+this.PasswordTextBox.Text+"'";
SqlConnection con = new SqlConnection(str);
SqlCommand cmd = new SqlCommand(query, con);
SqlDataReader dbr;
con.Open();
dbr = cmd.ExecuteReader();
int count = 0;
while (dbr.Read())
{
count = count + 1;
}
con.Close();
if (count == 1)
{
AdminConsoleForm objmain = new AdminConsoleForm();
objmain.Show(); //after login Redirect to second window
this.Hide();//after login hide the Login window
}
else if (count > 1)
{
MessageBox.Show("Duplicate username and password", "login page");
}
else
{
MessageBox.Show(" Username and Password Incorrect", "login page");
}
}
else
{
MessageBox.Show(" Password Empty", "login page");
}
}
else
{
MessageBox.Show(" Username Empty", "login page");
}
}
catch (Exception es)
{
MessageBox.Show(es.Message);
}
}
}
我使代码非常简单.如果需要安全性，可以加盐.
I have kept the code really simple. You can do salting if you want security.
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