confirm message box before deleting

When clicking on a button (BtnDelete) on my mypage.aspx, I want to show a messagebox to confirme before deleting. I tried with the code below but nothing happens and the information is deleted from the database without any message box appearing. can you add the appropriate code to the code below so that it will work. Thanks.

 Private Sub BtnDelete_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnDelete.Click

        'Shows a confirmation box when button delete is clicked
        BtnDelete.Attributes.Add("onclick", "return confirm('are you sure you want to delete? ');")

        'Declare objects and create a connection
        Dim myConnection As OdbcConnection = New OdbcConnection(ConfigurationSettings.AppSettings("connectionString"))
        Dim CmdString As String = "Delete From Kunder Where (ordernr = ? )"

        Dim myCommand As New OdbcCommand

            'Get parameter values from admin_kund.aspx
            Dim strOrdernr As String
            strOrdernr = Request.QueryString("ID")
            'Add parameters
            myCommand.Parameters.Add("ordernr", CStr(strOrdernr))


            myCommand.Connection = myConnection
            myCommand.CommandText = CmdString
        Catch ex As Exception
            End If
        End Try
    End Sub
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TimCotteeConnect With a Mentor Commented:
Hi viktor999,

Way to late to set the attribute! If you set it in the event handler for the button itself it has already been clicked and the form has already been posted back. You should set the onlick attribute in the page load event handler as you want it to apply to the button as it is rendered to the page initially.

Tim Cottee
Brainbench MVP for Visual Basic
You need this line in Page_Load event :


        'Shows a confirmation box when button delete is clicked
        BtnDelete.Attributes.Add("onclick", "return confirm('are you sure you want to delete? ');")


Even if you put the confirm() function in the onclick attribute in Page_Load, if you were to say No to the delete, the server-side code will still fire unless you explicitly cancel the event.  But there is a way to handle this strictly server-side:

1) Put a label control beneath your button but sets its Visible property to false.  Name it lblConfirm.
2) Set the CommandArgument property of your button to "Confirm" (u can use any string, but "Confirm" will do for this example).
3) In your server-side click event, do this:

Dim btn As Button = CType(sender, Button)
If btn.CommandArgument = "Complete" Then
     lblConfirm.Text = "Click Delete button again to confirm delete."
     lblConfirm.Visible = True
     btn.CommandArgument = "Delete"

Else If btn.CommandArgument = "Delete"
     ' execute your delete code here.

     lblConfirm.Text = ""
     lblConfirm.Visible = False
     btn.CommandArgument = "Confirm"

End If

You are using the label as a message box of sorts and the CommandArgument of the button to tell the click event whether you need to confrm or have confirmed.

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