/// <summary>
/// Populates and displays a custom popup.
/// </summary>
/// <example>
/// <code language="csharp"><![CDATA[
/// public static TValue MyCustomPopup<TValue>(
/// Rect position,
/// GUIContent valueLabel,
/// TValue value,
/// CustomPopupPopulateDelegate<TValue> populatePopupDelegate)
/// {
/// int popupControlID = GUIUtility.GetControlID(FocusType.Passive);
/// if (EditorGUI.DropdownButton(position, valueLabel, FocusType.Keyboard)) {
/// CustomPopupGUI.DisplayPopup(position, popupControlID, value, populatePopupDelegate);
/// }
/// return CustomPopupGUI.HandlePopupValueSelection(popupControlID, value);
/// }
/// ]]></code>
/// </example>
/// <typeparam name="TValue">The type of value that is being selected.</typeparam>
/// <param name="position">Absolute position of control on the GUI.</param>
/// <param name="popupControlID">Control ID of the popup.</param>
/// <param name="value">Current value selection.</param>
/// <param name="populatePopupDelegate">Delegate that populates popup menu.</param>
/// <seealso cref="HandlePopupValueSelection{TValue}(int, TValue)"/>
public static void DisplayPopup <TValue>(Rect position, int popupControlID, TValue value, CustomPopupPopulateDelegate <TValue> populatePopupDelegate)
{
SetActivePopupControl(popupControlID, value);
var popup = new CustomPopup <TValue>();
var context = new PopupContext <TValue>(popup, value);
populatePopupDelegate.Invoke(context);
popup.ShowAsDropdown(position);
}
public PopupContext(CustomPopup <TValue> popup, TValue currentValue)
{
this.Popup = popup;
this.CurrentValue = currentValue;
}