An unhandled exception of type 'System.Data.SqlClient.SqlExc

Enzo Enzo

9y1.1k

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.Windows.Forms;

using System.Data.SqlClient;

namespace test

{

public partial class Form1 : Form

{

public Form1()

{

InitializeComponent();

}

private void button1_Click(object sender, EventArgs e)

{

SqlConnection cn = new SqlConnection("server = localhost; user id = root; password=admin1234; database = test");

cn.Open();

SqlCommand cmd = new SqlCommand("SELECT * FROM users where username = '" + txtusername.Text + "', and passw =' " + txtpassword.Text + "'", cn);

SqlDataReader dr;

dr = cmd.ExecuteReader();

int count = 0;

while (dr.Read())

{

count += 1;

}

if (count == 1)

{

MessageBox.Show("OK");

Form2 f2 = new Form2();

f2.Show();

}

else if (count > 0)

{

MessageBox.Show("Duplicate username and password");

}

{

MessageBox.Show("username or password note correct");

}

txtusername.Clear();

txtpassword.Clear();

}

9 Replies

Know the answer? Post it — somebody with the same question will find it here.

Amit Gupta9y ago
@Enzo
It would have been much better, if you could ask another question on a seperate thread and closes this thread by marking the correct answer.

Anyway, generally windows do not allow to write directly on root drive (C:), unless your program runs as an administrator. I prefer you to use C:\ProgramData path.
Enzo Enzo9y ago
StreamWriter
Chetan Ranpariya9y ago
Did you read the article shared by me and Amit? The solution is available. You just need to apply.
Enzo Enzo9y ago
anyone can fix existing code above? I'm using mysql 5.7.

I don't know how to apply the connection.
Thanks
Amit Gupta9y ago
As per enclosed image of connection string, the type is MySql. The class you used is for MS Sql server that having different approach to connect the database.

Refer below link
https://www.codeproject.com/Articles/43438/Connect-C-to-MySQL
Chetan Ranpariya9y ago
https://www.codeproject.com/Articles/43438/Connect-C-to-MySQL this is a nice article about how use mysql with c#.net
Chetan Ranpariya9y ago
Your db server is mysql ? And you are trying to connect to it using sqlconnection class? That simply won't work.Use appreciate connection classes for mysql db operations.
Enzo Enzo9y ago
Thank you for your reply!

This is my connection

with this code.

SqlConnection cn = new SqlConnection("server = localhost; user id = root; password=admin1234; database = test");
cn.Open();
Amit Gupta9y ago
As per the exception, it seems that your connection string is having a problem.

Recheck all the fields such as server, userid etc.