[MySQL VB.Net] How to Show messagebox if a fields is blank

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Hi guys, im having trouble with my code here. I want to show messagebox if the user missed a textbox field blank.

Here's my code:

VB

Private Sub btnSave_Click(sender As System.Object, e As System.EventArgs) Handles btnSave.Click
        MySqlConn = New MySqlConnection
        MySqlConn.ConnectionString =
            "server=localhost;userid=root;password=ianp;database=database"
        Dim READER As MySqlDataReader

        

        Try
            MySqlConn.Open()
            Dim Query As String
            Query = "insert into database.appointment (AppointmentID, FirstName, MiddleName, LastName, Date, Time) values ('" & txtAppointmentID.Text & "','" & txtFNAppointment.Text & "', '" & txtMNAppointment.Text & "', '" & txtLNAppointment.Text & "', '" & dtDate.Text & "', '" & dtTime.Text & "')"
            COMMAND = New MySqlCommand(Query, MySqlConn)
            READER = COMMAND.ExecuteReader

            If txtFNAppointment.Text & txtMNAppointment.Text & txtLNAppointment.Text ="" Then
                MessageBox.Show("Please fill-up all the required fields !")

            Else
                MessageBox.Show("Successfully Saved Record")
autogenerate_id()
            End If

            MySqlConn.Close()

        Catch ex As MySqlException
            MessageBox.Show(ex.Message)
        Finally
            MySqlConn.Dispose()

        End Try

I have problems: When i left a field blank. It Shows the MessageBox "Please fill-up all the required fields !" but it saves in the mysql database. I want for it to abort the save until all the fields are filled-up. Any help will be appreciated. Thanks

Posted 13-Sep-15 17:47pm

Member 11981458

Updated 13-Sep-15 18:10pm

Wendelius

v2

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2 solutions

Solution 1

It's best to check each field separately. Also you need to exit the sub. So instead of

VB

If txtFNAppointment.Text & txtMNAppointment.Text & txtLNAppointment.Text ="" Then
MessageBox.Show("Please fill-up all the required fields !")

try

VB

If txtFNAppointment.Text = "" Or txtMNAppointment.Text = "" Or txtLNAppointment.Text ="" Then
   MessageBox.Show("Please fill-up all the required fields !")
   Return
End If

And what comes to your query, never concatenate values directly into the SQL statement. This leaves you open to SQL injections. Instead, use SqlParameter[^]. For more discussion, see Properly executing database operations, version 3, parameters[^]

Posted 13-Sep-15 18:07pm

Wendelius

Updated 13-Sep-15 18:11pm

v3

Comments

Member 11981458 14-Sep-15 0:34am

I tried both of them but even if you leave the fields blank, it always saves in the database. I would love for it to just show the messagebox. It will only save if all of the fields are filled-up

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DamithSL · Accepted Answer · 2015-09-13T18:19:00

Solution 2

validate and show message if any filed is missing, otherwise do the insert

VB

If String.IsNullOrWhiteSpace(txtFNAppointment.Text) or String.IsNullOrWhiteSpace(txtMNAppointment.Text) or String.IsNullOrWhiteSpace(txtLNAppointment.Text) Then
  MessageBox.Show("Please fill-up all the required fields !")
Else
   COMMAND = New MySqlCommand(Query, MySqlConn)
   COMMAND.ExcuteNonQuery()
End If

Posted 13-Sep-15 18:19pm

DamithSL

Comments

Member 11981458 14-Sep-15 0:31am

I tried both of them but even if you leave the fields blank, it always saves in the database. I would love for it to just show the messagebox. It will only save if all of the fields are filled-up

DamithSL 14-Sep-15 0:42am

can you show the code you tried?

Member 11981458 14-Sep-15 0:48am

I already got it to work sir Thanks a lot for your help. I just deleted the Code:
COMMAND = New MySqlCommand(Query, MySqlConn)
READER = COMMAND.ExecuteReader
Seems that this is the code that saves the database and not basing it on the IfElse statement.

DamithSL 14-Sep-15 0:58am

You are welcome!