[RESOLVED] how to set the text property on a checkedlistbox collection

[Marraco]

I had read on pages like this

that when adding objects to a CheckedListBox, it takes the .ToString() function of each added object as the text string.

I added instances of SortedDictionary as this

Friend Class MySortedDictionary
    inherits SortedDictionary(Of string, something)

    Public Overrides Function ToString() as string
        return "I want to show this"
    end Function
end Class
...
CheckedListBox1.Items.Add(new MySortedDictionary)
...

So, lets say, I want the text shown near each checkbox to be "I want to show this"
But instead, I are seeing

(Collection)

How is the right way?

(the overriden function ToString() as is never called)

[dglienna]

Nope. Read this:

http://www.c-sharpcorner.com/UploadF...arySample.aspx

[Marraco]

Nope. Read this:

http://www.c-sharpcorner.com/UploadF...arySample.aspx

I don't get it.

I don't want to add the sorted dictionary as the Item Collection of CheckedListBox1.

I want to add objects. One by one.

Since casually those object are SortedDictionary, the .ToString() function does not works, even when I override that function.

[Marraco]

Up to date, I used imported VB6 checked list box (from automatically updated VB6 code). They used a VB6 data structure, but now I want to leave all that legacy code, and going totally .NET way.

But I don't found how CheckedListBox is supossed to manage the shown string.
since two days ago, I are revolving the MS documentation, and found little.

In google I found things like

Me.CheckedListBox2.GetItemText

that property, simply don't exist. Also InteliSense don't show a SetItemText method, so I supposed that the object added should incorporate the String to be displayed.

then I found that It displays the .ToString function, but it looks like a clumsy solution, since many objects (like sortedDictionaries), can't be overridden ToString (it compiles, but does no effect as CheckedListBox matters, as if it acces the base class property instead of the overrided ToString() )

[dglienna]

Why can't you override it?

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        lstEmployees.Items.Add(New Employee("A", "B", DateTime.Now))
        lstEmployees.Items.Add(New Employee("C", "D", DateTime.Now))
        lstEmployees.Items.Add(New Employee("E", "F", DateTime.Now))

    End Sub
End Class

Public Class Employee
    Public FirstName As String
    Public LastName As String
    Public BirthDate As Date

    Public Sub New()
    End Sub

    Public Sub New(ByVal firstName, ByVal lastName, ByVal birthDate)
        Me.FirstName = firstName
        Me.LastName = lastName
        Me.BirthDate = birthDate
    End Sub

    Public Overrides Function ToString() As String
        Return FirstName & " " & LastName
    End Function
End Class

[Marraco]

Why can't you override it?

When employee Inherits from SortedDictionary, overriding Function ToString(), compiles without problem, but the CheckedListBox control uses the base class SortedDictionary.ToString instead of the Employee.ToString overrided one.

  ...
Public Class Employee
    Inherits SortedDictionary

  ...
    Public Overrides Function ToString() As String
        Return FirstName & " " & LastName
    End Function
End Class

[dglienna]

You need to add KEY and VALUE combos to a DICTIONARY

[jmedved]

(the overriden function ToString() as is never called)

There is always possibility of making "envelope" class like

Friend Class XXX

    Public Sub New()
        Me._dictionary = New MySortedDictionary()
    End Sub

    Private _dictionary As MySortedDictionary
    Public ReadOnly Property Dictionary() As MySortedDictionary
        Get
            Return Me._dictionary
        End Get
    End Property

    Public Overrides Function ToString() As String
        Return "I want to show this"
    End Function

End Class

and then adding it to list with

        CheckedListBox1.Items.Add(New XXX())

P.S. Using ToString usually works perfectly with this. I think that this behavior has something to do with inner working of CheckedListBox since if MyBase.ToString() was used, you would see something like:

System.Collections.Generic.SortedDictionary'2[System.String,something]

[Marraco]

You need to add KEY and VALUE combos to a DICTIONARY

In this case Values are dictionaries each one.

[Marraco]

There is always possibility of making "envelope" class like
...

I did that, although is weird from Microsoft to use a property which may not work on undocumented cases. It should implement a specific interface with support for key, checkedstate and on the fly changes.

It looks like it is a step back from VB6 version. So I searched for a .NET solution, but it looks like it don't exist.

[WRS_Darren]

Just spent hours working this out myself, thought I'd join and post as fairly recent thread...

You shouldn't override the tostring method - you just need to use the DisplayMember property of checklistbox (N.B It does NOT come up in intellisense!).

For example create a class like this:

Private Class CheckedListItem
Private myId As Long
Private myTextToDisplay As String

Public Sub New(ByVal Id As Long, ByVal TextToDisplay As String)
myId = Id
myTextToDisplay = TextToDisplay
End Sub

Public ReadOnly Property Id()
Get
Return myId
End Get
End Property

Public ReadOnly Property TextToDisplay()
Get
Return myTextToDisplay
End Get
End Property

End Class


...Then make sure you set the 'DisplayMember' as shown in following....

Private Sub loadUsersList()
Dim oUser As User
Dim oListItem As CheckedListItem

myUsersCol.loadAllUsers()

' Does not show up in intellisense!...
Me.ckLstUsers.DisplayMember = "TextToDisplay"

Me.ckLstUsers.Items.Clear()

oListItem = New CheckedListItem(0, "<All Users>")
Me.ckLstUsers.Items.Add(oListItem, True)

For Each oUser In myUsersCol
oListItem = New CheckedListItem(oUser.Id, oUser.UserFullName)
Me.ckLstUsers.Items.Add(oListItem, True)
Next
End Sub

(For ref: The displaymember property is inherited from ListControl so will be use-able with un-checked listboxes as well).

Hope that helps!

[Marraco]

Just spent hours...
Hope that helps!

It certainly helps!
Thanks Darren!