Solution 1 - Using recursive control search
I have done something similar with a dynamically generated form with a variable number of controls (textboxes, dropdowns, and checkboxes) and control state being data driven. I would not be looking to tie into the events of the generated controls (would require a jerky postback) but have a "Save" button and from that event do a recursive GetChildControls function that starts from the container holding your dynamic controls. Have a convention when assigning an id for each dynamic control so when you later loop back through them you can know which control is related to which record.
The recursive function:
Public Class ControlUtils
Shared Function GetChildControls(ByVal ctrl As Control, Optional ByVal ctrlType As Type = Nothing) As Control()
Dim controls As New ArrayList()
For Each c As Control In ctrl.Controls
' add this control and all its nested controls
If ctrlType Is Nothing OrElse ctrlType.IsAssignableFrom(c.GetType()) Then
controls.Add(c)
controls.AddRange(GetChildControls(c))
End If
Next
' return the result as an array of Controls
Return DirectCast(controls.ToArray(GetType(Control)), Control())
End Function
End Class
Basic idea with a contrived dynamic form...
A class to represent the database info:
Public Class Location
Public Property ID As Integer
Public Property Name As String
Public Property StartDate As Date
Public Property EndDate As Date
Shared Function GetSampleLocations() As List(Of Location)
Dim sample As New List(Of Location)
Dim loc As Location
For j = 1 To 5
loc = New Location
loc.ID = j
loc.Name = "Location " & j
loc.StartDate = Date.Today
loc.EndDate = Date.Today.AddDays(6 - j)
sample.Add(loc)
Next
Return sample
End Function
End Class
The class that has the methods to build the "form" and save its data:
Public Class LocationsDynamicForm
Dim _Locations As IEnumerable(Of Location)
Sub New(locations As IEnumerable(Of Location))
_Locations = locations
End Sub
Sub InsertEditForm(plc As PlaceHolder, setUserInput As Boolean)
'build and add controls to placeholder
Dim tbl As New Table
Dim r As TableRow
Dim c As TableCell
For Each loc As Location In _Locations
r = New TableRow
'add cell for location name
c = New TableCell
c.Controls.Add(New LiteralControl(loc.Name)) 'add plain text through literal control
r.Cells.Add(c)
'add cell for each day in the date range for current location
Dim currentDate As Date = loc.StartDate
Do Until currentDate > loc.EndDate
c = New TableCell
Dim chk As New CheckBox
chk.ID = "chkLocationDate_" & loc.ID & "_" & currentDate.Ticks
chk.Text = currentDate.ToShortDateString
If setUserInput Then
'set the check state based on current database value
Dim pretendValueCameFromDB As Boolean = True
chk.Checked = pretendValueCameFromDB
End If
c.Controls.Add(chk)
r.Cells.Add(c)
currentDate = currentDate.AddDays(1)
Loop
tbl.Rows.Add(r)
Next
plc.Controls.Add(tbl)
End Sub
Sub SaveForm(ByVal plc As PlaceHolder)
Dim ctl As Control
Dim controlIDParts() As String
Dim drp As DropDownList
Dim txt As TextBox
Dim chk As CheckBox
For Each ctl In ControlUtils.GetChildControls(plc, GetType(Control))
If ctl.GetType Is GetType(DropDownList) Then
drp = CType(ctl, DropDownList)
If drp.ID Like "drpIT_*" Then
controlIDParts = drp.ID.Split("_")
'update record...
End If
ElseIf ctl.GetType Is GetType(TextBox) Then
txt = CType(ctl, TextBox)
If txt.ID Like "txtIT_*" Then
controlIDParts = txt.ID.Split("_")
'update record...
End If
ElseIf ctl.GetType Is GetType(CheckBox) Then
chk = CType(ctl, CheckBox)
If chk.ID Like "chkLocationDate_*" Then
controlIDParts = chk.ID.Split("_")
Dim locationID = controlIDParts(1)
Dim ticks As Long = Val(controlIDParts(2))
Dim d As New Date(ticks)
'update record...
End If
End If
Next
'commit record changes...
End Sub
End Class
And its use inside the webform (assuming you have a save button and placeholder control):
Dim _Locations As List(Of Location)
Dim _LocationsForm As LocationsDynamicForm
Protected Sub Page_Init(sender As Object, e As EventArgs) Handles Me.Init
_Locations = Location.GetSampleLocations()
_LocationsForm = New LocationsDynamicForm(_Locations)
_LocationsForm.InsertEditForm(plcLocations, Not Me.IsPostBack)
End Sub
Protected Sub btnSave_Click(sender As Object, e As EventArgs) Handles btnSave.Click
_LocationsForm.SaveForm(plcLocations)
End Sub
Solution 2 - Use AddHandler with Dynamically added controls
This is closer to what you want, but requires a postback on each checkbox change. In your BindDays routine add these lines when you are adding the checkbox.
cbAvailible.AutoPostBack = True
AddHandler cbAvailible.CheckedChanged, AddressOf Insert_Click
You should trim the Handles keyword at the end of your sub Insert_Click signature. The Handles is nice when you have foreknowledge of the control(s) you will be handling but the controls don't exist at design time.
Private Sub Insert_Click(sender As Object, e As EventArgs)
' I want to get here al the checkbox id and insert the values to a databse
Dim chk As CheckBox = CType(sender, CheckBox)
Label1.Text = "ID = " & chk.ID & ", Checked = " & chk.Checked
End Sub
I'm not sure how you are persisting your 'LocationData' across postbacks or adding it to the web page but I was able to get a modified version of your code working.