[rdxdz]

@User_Name = ?????

---

مثال
Dim result As Decimal = total - Convert.ToDecimal(inputValue)

command.Parameters.AddWithValue("@result", result)

---

Login ?

كود :

Private Sub btnLogin_Click(sender As Object, e As EventArgs) Handles btnLogin.Click
       Dim username As String = txtUsername.Text
       Dim password As String = txtPassword.Text
       Dim connectionString As String = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=yourdatabase.accdb;"
       Dim query As String = "SELECT COUNT(*) FROM Users WHERE Username = @username AND Password = @password"

       Using connection As New OleDbConnection(connectionString)
           Using command As New OleDbCommand(query, connection)
               command.Parameters.AddWithValue("@username", username)
               command.Parameters.AddWithValue("@password", password)

               connection.Open()
               Dim result As Integer = Convert.ToInt32(command.ExecuteScalar())

               If result > 0 Then
                   MessageBox.Show("Login successful!")
               Else
                   MessageBox.Show("Invalid username or password.")
               End If
           End Using
       End Using
   End Sub