xwt/Xwt.WPF/Xwt.WPFBackend/DropDownButton.cs

113 строки
3.1 KiB
C#

//
// DropDownButton.cs
//
// Author:
// Eric Maupin <ermau@xamarin.com>
//
// Copyright (c) 2012 Xamarin, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
using System;
using System.Linq;
using System.Windows;
using System.Windows.Controls.Primitives;
using SWC = System.Windows.Controls;
namespace Xwt.WPFBackend
{
public class DropDownButton
: SWC.Primitives.ToggleButton, IWpfWidget
{
public DropDownButton()
{
Checked += OnChecked;
}
public event EventHandler<MenuOpeningEventArgs> MenuOpening;
public WidgetBackend Backend
{
get;
set;
}
protected override System.Windows.Size MeasureOverride (System.Windows.Size constraint)
{
// HACK: This is a hack to fix a size calculation issue with buttons.
// For some reason, base.MeasureOverride doesn't return the correct size
// when using infinite,infinite as constraint, unless a previous call with
// concrete numbers has been made.
base.MeasureOverride (new System.Windows.Size (0, 0));
var s = base.MeasureOverride (constraint);
return Backend.MeasureOverride (constraint, s);
}
private void OnChecked (object sender, RoutedEventArgs routedEventArgs)
{
if (!IsChecked.HasValue || !IsChecked.Value)
return;
var args = new MenuOpeningEventArgs ();
var opening = this.MenuOpening;
if (opening != null)
opening (this, args);
var menu = args.ContextMenu;
if (menu == null) {
IsChecked = false;
return;
}
string text = Content as string;
if (!String.IsNullOrWhiteSpace (text)) {
SWC.MenuItem selected = menu.Items.OfType<SWC.MenuItem>().FirstOrDefault (i => i.Header as string == text);
if (selected != null)
selected.IsChecked = true;
}
menu.Closed += OnMenuClosed;
menu.PlacementTarget = this;
menu.Placement = PlacementMode.Bottom;
menu.IsOpen = true;
}
private void OnMenuClosed (object sender, RoutedEventArgs e)
{
var menu = sender as SWC.ContextMenu;
if (menu != null)
menu.Closed -= OnMenuClosed;
IsChecked = false;
}
public class MenuOpeningEventArgs
: EventArgs
{
public SWC.ContextMenu ContextMenu
{
get;
set;
}
}
}
}