WPF - FindName Returns null when it should not

Question

FindName is broken for me :(

The object I am looking for is there. I have proof.

Here is the scenario:

ToggleButton button = (ToggleButton)s         


        

Answer 1

I would suggest to avoid using FindName function, based on my experience, expecially problematic when you try to find something in the DataTemplate applied to some control. Instead , if it possible (based on your software architecture) declare Popup in XAML and refer to it like resource or use Binding to set some Model property to it's reference. Good luck.

Answer 2

I have meet the same question now, but i use the method like below:

    #region Override - OnApplyTemplate

    public override void OnApplyTemplate()
    {
        base.OnApplyTemplate();

        this.PART_ListViewLeft      = GetTemplateChild(cPART_ListViewLeft)      as ListView;
        this.PART_ListViewCenter    = GetTemplateChild(cPART_ListViewCenter)    as ListView;
        this.PART_ListViewRight     = GetTemplateChild(cPART_ListViewRight)     as ListView;

        this.PART_GridViewLeft      = GetTemplateChild(cPART_GridViewLeft)      as DsxGridView;
        this.PART_GridViewCenter    = GetTemplateChild(cPART_GridViewCenter)    as DsxGridView;
        this.PART_GridViewRight     = GetTemplateChild(cPART_GridViewRight)     as DsxGridView;
        if(this.PART_ListViewLeft!=null)
            this.PART_ListViewLeft      .AlternationCount = this.AlternatingRowBrushes.Count;
        if(this.PART_ListViewCenter!=null)
            this.PART_ListViewCenter    .AlternationCount = this.AlternatingRowBrushes.Count;
        if(this.PART_ListViewRight!=null)
            this.PART_ListViewRight     .AlternationCount = this.AlternatingRowBrushes.Count;
      //  ApplyTempleted = true;
        CreateColumnLayout();
    }
    #endregion

if the Control is dynamic create and of which or whose container the 'Visibility' is set to hide or Collapsed ,then the code "this.PART_ListViewLeft = GetTemplateChild(cPART_ListViewLeft) as ListView;" will return null always, the reason is clearly: the datatemplete has not yet been applied before OnApplyTemplate being called!!!!!!! so your question should be the same one!! good luck!