dfDropdown.OpenPopup C# (CSharp) Method

    public void OpenPopup()
    {
        if( popup != null || items.Length == 0 )
            return;

        var popupSize = calculatePopupSize();

        // Create the popup list and set all necessary properties
        popup = GetManager().AddControl<dfListbox>();
        popup.name = this.name + " - Dropdown List";
        popup.gameObject.hideFlags = HideFlags.DontSave;
        popup.Atlas = this.Atlas;
        popup.Anchor = dfAnchorStyle.Left | dfAnchorStyle.Top;
        popup.Color = this.Color;
        popup.Font = this.Font;
        popup.Pivot = dfPivotPoint.TopLeft;
        popup.Size = popupSize;
        popup.Font = this.Font;
        popup.ItemHeight = this.ItemHeight;
        popup.ItemHighlight = this.ItemHighlight;
        popup.ItemHover = this.ItemHover;
        popup.ItemPadding = this.TextFieldPadding;
        popup.ItemTextColor = this.TextColor;
        popup.ItemTextScale = this.TextScale;
        popup.Items = this.Items;
        popup.ListPadding = this.ListPadding;
        popup.BackgroundSprite = this.ListBackground;
        popup.Shadow = this.Shadow;
        popup.ShadowColor = this.ShadowColor;
        popup.ShadowOffset = this.ShadowOffset;
        popup.BringToFront();

        // If there is a modal control/window up that displays this dropdown,
        // need to ensure that it is able to receive input
        if( dfGUIManager.GetModalControl() != null )
        {
            dfGUIManager.PushModal( popup );
        }

        if( popupSize.y >= MaxListHeight && listScrollbar != null )
        {

            var scrollGO = GameObject.Instantiate( listScrollbar.gameObject ) as GameObject;
            var activeScrollbar = scrollGO.GetComponent<dfScrollbar>();

            var p2u = PixelsToUnits();
            var right = popup.transform.TransformDirection( Vector3.right );
            var scrollbarPosition = popup.transform.position + right * ( popupSize.x - activeScrollbar.Width ) * p2u;

            popup.AddControl( activeScrollbar );
            popup.Width -= activeScrollbar.Width;
            popup.Scrollbar = activeScrollbar;

            popup.SizeChanged += ( control, size ) =>
            {
                activeScrollbar.Height = control.Height;
            };

            activeScrollbar.transform.parent = popup.transform;
            activeScrollbar.transform.position = scrollbarPosition;

            activeScrollbar.Anchor = dfAnchorStyle.Top | dfAnchorStyle.Bottom;
            activeScrollbar.Height = popup.Height;

        }

        // Position the dropdown and set its rotation to the same world rotation
        // as this control
        var popupPosition = calculatePopupPosition( (int)popup.Size.y );
        popup.transform.position = popupPosition;
        popup.transform.rotation = this.transform.rotation;

        // Attach important events
        popup.SelectedIndexChanged += popup_SelectedIndexChanged;
        popup.LeaveFocus += popup_LostFocus;
        popup.ItemClicked += popup_ItemClicked;
        popup.KeyDown += popup_KeyDown;

        // Make sure that the selected item is visible
        popup.SelectedIndex = Mathf.Max( 0, this.SelectedIndex );
        popup.EnsureVisible( popup.SelectedIndex );

        // Make sure that the popup has input focus
        popup.Focus();

        // Notify any listeners that the popup has been displayed
        if( DropdownOpen != null )
        {
            bool overridden = false;
            DropdownOpen( this, popup, ref overridden );
        }
        Signal( "OnDropdownOpen", this, popup );
    }