在WPF窗口StateChanging事件 [英] Window StateChanging event in WPF
问题描述
我需要处理的WPF应用程序的权利之前,它会最小化,而不是当它已经存在。 我发现Window对象StateChanged,但它触发时,Window对象是已经在最小化状态,那么一切都太迟了。
I need to handle WPF application right before it goes Minimize, not when it's already there. I found on Window object StateChanged, but it fires when Window object is already in Minimize state, then it's too late.
所以,我需要的东西,如StateChanging事件来处理,而Window对象仍处于previous状态。
So, I need something like "StateChanging" event to handle, while Window object is still in previous state.
是否有可能创造这样的事件?
Is it possible to create such event ?
推荐答案
找到Windows消息呼吁窗口右侧前尽量减少使用间谍++。第一个被称为是WM_WINDOWPOSCHANGING。 我不知道窗户上-32000移动窗口时,最大限度地减少寡妇,这些都是在WM_WINDOWPOSCHANGING的PARAMS -32000定位点。虽然,我已经测试只有在Vista上。 <一href="http://blogs.msdn.com/oldnewthing/archive/2004/10/28/249044.aspx">http://blogs.msdn.com/oldnewthing/archive/2004/10/28/249044.aspx
Found windows messages called on window right before minimize using Spy++. First one that is called is WM_WINDOWPOSCHANGING. I didn't know windows is moving window on -32000, -32000 location point when minimizing widow, and those were the params in WM_WINDOWPOSCHANGING. Though, I have tested is only on Vista. http://blogs.msdn.com/oldnewthing/archive/2004/10/28/249044.aspx
这里使用code被张贴由尼尔<一href="http://stackoverflow.com/questions/386484/how-can-i-only-allow-uniform-resizing-in-a-wpf-window/696266#696266">here
code used here was posted by Nir here
下面是示例code
XAML
<Window x:Class="WindowStateTest2.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Window1" Height="300" Width="300">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition Height="*"></RowDefinition>
</Grid.RowDefinitions>
<Button Click="btnClear_Click" Grid.Row="0" x:Name="btnClear">Clear</Button>
<TextBox Name="txt" VerticalScrollBarVisibility="Visible" Grid.Row="2"></TextBox>
</Grid>
</Window>
C#
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Windows.Interop;
using System.Runtime.InteropServices;
namespace WindowStateTest2
{
/// <summary>
/// Interaction logic for Window1.xaml
/// </summary>
public partial class Window1 : Window
{
public Window1()
{
InitializeComponent();
this.StateChanged += new EventHandler(Window1_StateChanged);
this.SourceInitialized += new EventHandler(Window1_SourceInitialized);
}
#region Event handlers
void btnClear_Click(object sender, RoutedEventArgs e)
{
this.txt.Text = string.Empty;
}
void Window1_SourceInitialized(object sender, EventArgs e)
{
AttachWndProc();
}
void Window1_StateChanged(object sender, EventArgs e)
{
if (this.WindowState == WindowState.Minimized)
Console.WriteLine("SC: " + this.WindowState);
}
#endregion
#region Const
private int SYSCOMMAND = 0x0112;
private int SC_MINIMIZE = 0xf020;
private int WINDOWPOSCHANGING = 0x0046;
#endregion
private void AttachWndProc()
{
HwndSource source = HwndSource.FromHwnd(new WindowInteropHelper(this).Handle);
source.AddHook(new HwndSourceHook(WndProc));
}
[StructLayout(LayoutKind.Sequential)]
internal struct WINDOWPOSPARAMS
{
public IntPtr hwnd;
public IntPtr hwndInsertAfter;
public int x;
public int y;
public int cx;
public int cy;
public int flags;
}
private IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
{
if (msg == WINDOWPOSCHANGING)
{
WINDOWPOSPARAMS param = (WINDOWPOSPARAMS)Marshal.PtrToStructure(lParam, typeof(WINDOWPOSPARAMS));
if (param.x == -32000 && param.y == -32000)
{
Output("");
// EVENT WOULD BE RAISED HERE
Output("State before minimize:");
Output(string.Format("CurrentState: {0}", this.WindowState));
Output(string.Format("Location {0} {1}: ", this.Top, this.Left));
Output("");
}
}
// process minimize button
if (msg == SYSCOMMAND && SC_MINIMIZE == wParam.ToInt32())
{
Output("Minimize clicked");
}
handled = false;
return IntPtr.Zero;
}
public void Output(object output)
{
this.txt.Text += output.ToString();
this.txt.Text += Environment.NewLine;
}
}
}
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