Checkpoints in functions VB.NET - vb.net

Question

I have a function that check validity of inserted data of a form, and in this function I have to ask some confirmation from user, and this confirmation need to be asked outside of the function, so if I hit one of this confirmations, I create the message and send out the validation function, user confirms or not and the function would called again
so here is the problem: I need to put some checkpoints in my function so when I call the validation function I jump to that checkpoint with the selected confirmation from user and run the validation function from that checkpoint
1: is this possible at all?
2: any ideas to do this?
Edit 1: I'm doing this validation in my business layer and can not show any message boxes from there, I just create the message and return it to the UI layer and the answer get from the user and function call again with this answer but I don't want to run the function from beginning and need to run it from where I left
Public Class BL
Private Queue As Queue(Of String)
Public Sub New()
Dim checkpoints = New String(){"CheckPoint1","CheckPoint2","CheckPoint3"}
checkpoints.ToList.ForEach(Function(item) <b>Queue.Enqueue(item)</b>)
End Sub
Public Function Func(ByVal res As Response,ParamArray ByVal params As String()) As Response
Dim response As Response
Dim chk = Queue.Dequeue()
GoTo chk
CheckPoint1:
'Do some stuff
response = New Response(Response.ResponseType.Message,"Are you sure you wanna do this?")
Return response
CheckPoint2:
If(res.Type = Response.ResponseType.ResponseBack)
Dim r As DialogResult = Convert.ChangeType([Enum].Parse(GetType(DialogResult),res.Message),GetType(DialogResult))
If (r= DialogResult.OK)
'Do stuffs on DialogResult.Yes
Else
'Do stuffs on DialogResult.No
End If
'Do other stuffs with database
End If
' Do other stuff
response = New Response(Response.ResponseType.Message,"You should do this!!OK?")
Return response
CheckPoint3:
'Do stuff like CheckPoint1
End Function
End Class
Public Class Response
Friend Enum ResponseType
Message
Result
ResponseBack
None
End Enum
Friend Message As String
Friend Type As ResponseType
Friend Sub New(ByVal type As ResponseType,msg As String)
Message=msg
Type= type
End Sub
End Class
Public Class Form1
Public Sub New()
' This call is required by the designer.
InitializeComponent()
Dim BL As New BL()
' Add any initialization after the InitializeComponent() call.
Dim rese As Response
Do
rese =BL.Func(Nothing)
BL.Func(new Response(Response.ResponseType.ResponseBack,if(MessageBox.Show(rese.Message).ToString())))
Loop Until rese.Type <> Response.ResponseType.Result
MessageBox.Show(if(rese.Message="True","OK","ERROR"))
End Sub
End Class

Answer 1

This is not an objective answer but could help. You need some sort of class that contains question and answers. Your validation class would return a list of question (are you sure?).
Class ValidationOutput
ValidationId
Message
Result
End Class
After calling your validation function, you get a list of validation that need extra information from the user. This can be handle outside of the validation function. When you get the extra information, call the validation again and pass the same list as parameter. When validating, look at the list to see if all the extra information needed is there.

Answer 2

I believe your business logic should not deal with user interactions and split to two parts.
However, if you prefer this way, you can use callbacks. Define a delegate parameter for your validation/business method and call that delegate when you need confirmation. According to return value continue to save operation or not.
You can check link below for delegate passing to a method.
https://learn.microsoft.com/en-us/dotnet/visual-basic/programming-guide/language-features/delegates/how-to-pass-procedures-to-another-procedure

Answer 3

This should work for you:
Public Class BL
Private Queue As Queue(Of String)
Private _checkpoints As Dictionary(Of String, Func(Of Response, Response)) = New Dictionary(Of String, Func(Of Response, Response)) From
{
{ "CheckPoint1", Function (res) New Response(Response.ResponseType.Message, "Are you sure you wanna do this?") },
{ "CheckPoint2", Function (res)
If (res.Type = Response.ResponseType.ResponseBack)
Dim r As DialogResult = CType(Convert.ChangeType([Enum].Parse(GetType(DialogResult), res.Message), GetType(DialogResult)), DialogResult)
If (r = DialogResult.OK)
'Do stuffs on DialogResult.Yes
Else
'Do stuffs on DialogResult.No
End If
'Do other stuffs with database
End If
' Do other stuff
Return New Response(Response.ResponseType.Message, "You should do this!!OK?")
End Function
},
{ "CheckPoint3", Function (r) New Response(Response.ResponseType.Message, "Are you sure you wanna do this?") }
}
Public Sub New()
_checkpoints.ToList().ForEach(Sub(item) Queue.Enqueue(item.Key))
End Sub
Public Function Func(ByVal res As Response, ParamArray ByVal params As String()) As Response
Dim chk = Queue.Dequeue()
Return _checkpoints(chk).Invoke(res)
End Function
End Class
Basically this creates a Dictionary(Of String, Func(Of Response, Response)) that maps a String to a Func(Of Response, Response) that returns the Response that you want.
There would be a couple of variations on this that might suit you better, but perhaps you could let me know if this does the job or not for you and I could suggest other options if need be.