how to retrieve data from mysql database and display it into textbox in c#

[nehpets]

this is the code that i tried to make but its not working..nothing happen to the output..i need some help..please..i am a beginner in c#....thanks!!!

private void button1_Click(object sender, EventArgs e)
{
string input = textBox3.Text;
connectdatabase();
string wow = "SELECT `CustomerName` FROM `CustomerInfo`";
MySqlCommand wowcmd = new MySqlCommand(wow, connection);
MySqlDataReader Reader;
Reader = wowcmd.ExecuteReader();
while (Reader.Read())
{
if (input == Convert.ToString(Reader))
{
textBox5.Text = Convert.ToString(Reader);
}
}


}

[arvindps]

what is connectdatabase() ?. is it a function that passes a connection string ?

in normal practise

MySqlConnection mys = new MySqlConnection("connect_string");

where connect string contains server,username,password,database

[arie]

You may find this two pages usefull:

http://www.geekpedia.com/tutorial228...ctororNet.html

http://www.geekpedia.com/tutorial139...-and-ODBC.html

The first one uses connector, and when you install and reference it in your project, you will have MySqlConnection class (the one arvindps mentioned) avaliable.

The second approach requires that the end-user has ODBC drivers installed.

You should also pay attention to exceptions. Use try{}catch(){} statements or using{} statements with connections, commands and readers (I personally like the the using{} statement more, because it takes care of closing thing s instead of me:)

I also noticed that in your code you compare the customernames you get with the text in your textbox3. This way, if there are more than one customers with the same name, you'll get only the last one.

And about MySqlDataReader class. I'm not sure if you can use it like that. Can you really just Convert it to string? I'd rather do this:

Reader.GetString(<index of the column in the output you want to read, in your case: 0>)
 

[adriancs]

Option 1:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using MySql.Data.MySqlClient;
 
namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
 
        private void button1_Click(object sender, EventArgs e)
        {
            string input = textBox1.Text.Trim();
            string conn = "server=localhost;user=root;password=qwerty;database=customer;";
            MySqlConnection myconn = new MySqlConnection(conn);
            string sql = "SELECT `CustomerName` FROM `CustomerInfo` WHERE `CustomerName` = '" + input + "';";
            MySqlDataAdapter da = new MySqlDataAdapter(sql, myconn);
            DataTable dt = new DataTable();
            da.Fill(dt);
 
            if (dt.Rows.Count == 0)
            {
                MessageBox.Show(input + " is not exist.", "Not Exists");
            }
            else
            {
                textBox2.Text = dt.Rows[0][0] + "";
            }
        }
    }
}

Option 2:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using MySql.Data.MySqlClient;
 
namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
 
        private void button1_Click(object sender, EventArgs e)
        {
            string input = textBox1.Text.Trim();
            string conn = "server=localhost;user=root;password=qwerty;database=customer;";
            MySqlConnection myconn = new MySqlConnection(conn);
            string sql = "SELECT `CustomerName` FROM `CustomerInfo`;";
            MySqlDataAdapter da = new MySqlDataAdapter(sql, myconn);
            DataTable dt = new DataTable();
            da.Fill(dt);
 
            if (dt.Rows.Count == 0)
            {
                MessageBox.Show("No data found.", "No Data");
            }
            else
            {
                foreach (DataRow dr in dt.Rows)
                {
                    if (dr[0] + "" == input)
                    {
                        textBox2.Text = dr[0] + "";
                        break;
                    }
                }
            }
        }
    }
}