[Uija]

Hello everyone ,
at the beginning of my program you have to register. But what if the username already exists?I already wrote something , but It does nothing 😶 (when I click on the button it says nothing..)
Can someone say me what did I wrong ?

My code :

Imports System.Data.OleDb
Public Class Form1


   Dim boolUsernameExists As Boolean = False

   Private Sub FlatButton1_Click(sender As Object, e As EventArgs) Handles FlatButton1.Click
       Dim strUsername As String = FlatTextBox1.Text
       Try
           If String.IsNullOrEmpty(strUsername) Then
       
               Return
           End If

           Using dbConnection As OleDbConnection = New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|\bin\Debug\Arbeiter.mdb")

               dbConnection.Open()
               Using dbCommand As OleDbCommand = New OleDbCommand("Select Count(*) FROM Arbeiter WHERE Forname LIKE?", dbConnection) ' "Arbeiter" is the name of the table and "Forname" is the username
                   dbCommand.Parameters.AddWithValue("@p1", strUsername)
                   Dim result As Integer = DirectCast(dbCommand.ExecuteScalar(), Integer)
                   If result > 0 Then
                       boolUsernameExists = True
                       MsgBox("Username already exists")
                   Else
                   
                   End If
               End Using
               dbConnection.Close()
           End Using

           If boolUsernameExists Then
               MsgBox("Username already exists")
               Return
           End If

       Catch ex As Exception

       End Try
   End Sub

[aneeshkollam5]

Using dbCommand As OleDbCommand = New OleDbCommand("Select * FROM Arbeiter WHERE Forname ='" & strUsername & "'", dbConnection)

Dim dr As OleDbDataReader = dbCommand.ExecuteReader()
If dr.HasRows Then
boolUsernameExists = True
MsgBox("Username already exists")
Else

End If

[Uija]

Using dbCommand As OleDbCommand = New OleDbCommand("Select * FROM Arbeiter WHERE Forname ='" & strUsername & "'", dbConnection)
               
                  Dim dr As OleDbDataReader = dbCommand.ExecuteReader()
                  If dr.HasRows Then
                      boolUsernameExists = True
                      MsgBox("Username already exists")
                  Else
                 
                  End If

Thank you ! This works 🤗