Fixed height radListBox

[FrancoP]

Good morning.

    I want to programmatically add a fixed height radListBox in the Form_Load. The height should be calculated accordingly to the number of items in the listbox. But the GetItemHeight method returns zero in the Form_Load. If I add a test button, and in the Click event perform the GetItemHeight, the result is 16, ok. Another problem is that I have to add 2 (magic number?) to the total height, otherwise the vertical scrollbar will appear. How can I solve these 2 problems?

 

Thank you

[Victor]

Hi FrancoP,

Thank you for the questions.
 

You can go around the first issue by calculating the height in the Shown event of your form. I am afraid that you will have to make do with the magic number for now. We have plans to improve the virtualization of RadListBox in a future release, which will cause some glitches in the layout to disappear.

Please write again if you have other questions.
 

Best wishes,
Victor
the Telerik team

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[FrancoP]

Thank you for your answer, but I can't use the shown event. I have to calculate the height of the item before the listbox be display. Is there a method to do so?

[Victor]

Hello FrancoP,

GetItemHeight() method always returns 16 in the Form load event handler when I am testing it. Are you sure your items are added to the list box? If they are, please post a support ticket and attach a sample application so that I can debug it and provide a direct answer; this could be a potential issue. I am looking forward to your reply.

Kind regards,
Victor
the Telerik team

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[FrancoP]

Hello Victor,

I tried with a code like this (VB):

 

Imports Telerik.WinControls.UI

 

Public Class Form1

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

    Dim rlb As New RadListBox

 

    Dim rlbi As New RadListBoxItem("Item1")

    rlb.Items.Add(rlbi)

    Dim h As Integer = rlb.GetItemHeight(0)

 

    Controls.Add(rlb)

 

  End Sub

End Class

 

and the value of ‘h’ is 0. If I calculate h after the ‘Controls.Add(rlb)’ I get 16 as expected.

Is there a method to get the item height before adding the radListBox to the controls of the form?

 

Kind regards

[Victor]

Hi FrancoP,

You need to add the RadListBox object to the Controls collection before calling the GetItemHeight() method. Simply move your Controls.Add(rlb) call to just before the Dim h As Integer  = rlb.GetItemHeight(0) statement.

Please write again if you need further assistance.

Best wishes,
Victor
the Telerik team

Instantly find answers to your questions on the new Telerik Support Portal.
Watch a video on how to optimize your support resource searches and check out more tips on the blogs.