check if username exists in database with vb net
In this video we will discuss how to check if username exists in database using vb.net and sql server.
As we type in the the username in the username textbox and then click check availability button we want to check in the database table if that username is already in use.
If the username is already taken, then we want to display a message stating username already taken.
If the username is not taken yet, then we want to display a message stating username available.
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the code is as under:
Imports System.Data
Imports System.Data.SqlClient
Public Class frmavailability
Dim con As SqlConnection
Dim cmd As SqlCommand
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
Timer1.Enabled = True
Timer1.Interval = 1000
PictureBox1.Image = My.Resources.ResourceManager.GetObject("progress")
PictureBox1.Visible = True
End Sub
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
If Timer1.Interval = 2000 Then
con = New SqlConnection("server=localhost;data source=compaq-pc;database=youtube;integrated security=SSPI")
Dim query As String = "select username from login where username=@username"
con.Open()
cmd = New SqlCommand(query, con)
cmd.Parameters.AddWithValue("@username", usernameTextBox.Text)
Dim dr As SqlDataReader
dr = cmd.ExecuteReader()
While dr.Read
Label3.BackColor = Color.Red
Label3.ForeColor = Color.White
PictureBox1.Visible = False
Label3.Text = "already taken"
con.Close()
Exit Sub
End While
Label3.Text = "available"
Label3.BackColor = Color.Green
Label3.ForeColor = Color.White
PictureBox1.Visible = False
con.Close()
End If
Timer1.Interval += 1000
End Sub
Private Sub usernameTextBox_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles usernameTextBox.TextChanged
Label3.Text = ""
End Sub
End Class