原文:
[WPF疑难] 模式窗口被隐藏后重新显示时变成了非模式窗口
[WPF疑难] 模式窗口被隐藏后重新显示时变成了非模式窗口
周银辉
现象：
大家可以试试下面这个很有趣但会带来Defect的现象：当我们将子窗口按照ShowDialog()的方式显示出来的时候，很明显该窗口是模式化的（即主窗口等待该窗口的返回，主窗口将不相应用户输入），但如果此时将子窗口的Visibility设置成Visibility.Hidden来隐藏窗口，然后再将Visibility设置成Visibility.Visible来再次显示子窗口，此后子窗口便是非模式的了（即主窗口和子窗口一样相应用户输入）
案例：
当用户不操作软件达到一定的时间间隔后，软件会隐藏该软件当前显示的所有窗口，并弹出“锁定窗口”，当用户手动解锁后，“锁定窗口”隐藏，其它所有窗口重新显示出来。
对于上述案例中的窗口，如果使用设置Visibility的方式来显示或隐藏窗口，如果被隐藏的窗口是模式对话框的化，便会在重新显示时出现上述问题。
解决方案：
可以用一个相对简单的方式来解决这个问题：“隐藏” 就是 "看不见”， “把窗口扔到显示屏幕之外”就是“看不见”。（这属于“WO，KAO"类的方案，而非”WOW，SAI“，不过却能很好地工作。”写软件就是骗入“----用高科技骗人的眼睛、耳朵，写游戏就更得会骗人了）
代码：
public
class
WindowVisibilityHelper : DependencyObject
{
public static bool GetIsVisible(DependencyObject obj)
{
return ( bool )obj.GetValue(IsVisibleProperty);
}
public static void SetIsVisible(DependencyObject obj, bool value)
{
obj.SetValue(IsVisibleProperty, value);
}
public static readonly DependencyProperty IsVisibleProperty =
DependencyProperty.RegisterAttached( " IsVisible " , typeof ( bool ),
typeof (WindowVisibilityHelper),
new PropertyMetadata( true , IsVisiblePropertyChangedCallback));
private static void IsVisiblePropertyChangedCallback(DependencyObject obj,
DependencyPropertyChangedEventArgs e)
{
var window = (Window)obj;
var visible = ( bool )e.NewValue;
if ( ! visible)
{
SetWindowState(window, window.WindowState);
if (window.WindowState == WindowState.Maximized)
{
window.WindowState = WindowState.Normal;
}
SetWindowLocation(window, new Point(window.Left, window.Top));
window.Left = - 100000 ;
window.Top = - 100000 ;
SetWindowIsShowInTaskBar(window, window.ShowInTaskbar);
window.ShowInTaskbar = false ;
}
else
{
window.WindowState = GetWindowState(window);
Point loc = GetWindowLocation(window);
window.Left = loc.X;
window.Top = loc.Y;
window.ShowInTaskbar = GetWindowIsShowInTaskBar(window);
window.Activate();
window.BringIntoView();
}
}
private static Point GetWindowLocation(DependencyObject obj)
{
return (Point)obj.GetValue(WindowLocationProperty);
}
private static void SetWindowLocation(DependencyObject obj, Point value)
{
obj.SetValue(WindowLocationProperty, value);
}
private static readonly DependencyProperty WindowLocationProperty =
DependencyProperty.RegisterAttached( " WindowLocation " , typeof (Point),
typeof (WindowVisibilityHelper), new UIPropertyMetadata( new Point()));
private static WindowState GetWindowState(DependencyObject obj)
{
return (WindowState)obj.GetValue(WindowStateProperty);
}
private static void SetWindowState(DependencyObject obj, WindowState value)
{
obj.SetValue(WindowStateProperty, value);
}
private static readonly DependencyProperty WindowStateProperty =
DependencyProperty.RegisterAttached( " WindowState " , typeof (WindowState),
typeof (WindowVisibilityHelper), new UIPropertyMetadata(WindowState.Normal));
private static bool GetWindowIsShowInTaskBar(DependencyObject obj)
{
return ( bool )obj.GetValue(WindowIsShowInTaskBarProperty);
}
private static void SetWindowIsShowInTaskBar(DependencyObject obj, bool value)
{
obj.SetValue(WindowIsShowInTaskBarProperty, value);
}
private static readonly DependencyProperty WindowIsShowInTaskBarProperty =
DependencyProperty.RegisterAttached( " WindowIsShowInTaskBar " , typeof ( bool ),
typeof (WindowVisibilityHelper), new UIPropertyMetadata( true ));
}
{
public static bool GetIsVisible(DependencyObject obj)
{
return ( bool )obj.GetValue(IsVisibleProperty);
}
public static void SetIsVisible(DependencyObject obj, bool value)
{
obj.SetValue(IsVisibleProperty, value);
}
public static readonly DependencyProperty IsVisibleProperty =
DependencyProperty.RegisterAttached( " IsVisible " , typeof ( bool ),
typeof (WindowVisibilityHelper),
new PropertyMetadata( true , IsVisiblePropertyChangedCallback));
private static void IsVisiblePropertyChangedCallback(DependencyObject obj,
DependencyPropertyChangedEventArgs e)
{
var window = (Window)obj;
var visible = ( bool )e.NewValue;
if ( ! visible)
{
SetWindowState(window, window.WindowState);
if (window.WindowState == WindowState.Maximized)
{
window.WindowState = WindowState.Normal;
}
SetWindowLocation(window, new Point(window.Left, window.Top));
window.Left = - 100000 ;
window.Top = - 100000 ;
SetWindowIsShowInTaskBar(window, window.ShowInTaskbar);
window.ShowInTaskbar = false ;
}
else
{
window.WindowState = GetWindowState(window);
Point loc = GetWindowLocation(window);
window.Left = loc.X;
window.Top = loc.Y;
window.ShowInTaskbar = GetWindowIsShowInTaskBar(window);
window.Activate();
window.BringIntoView();
}
}
private static Point GetWindowLocation(DependencyObject obj)
{
return (Point)obj.GetValue(WindowLocationProperty);
}
private static void SetWindowLocation(DependencyObject obj, Point value)
{
obj.SetValue(WindowLocationProperty, value);
}
private static readonly DependencyProperty WindowLocationProperty =
DependencyProperty.RegisterAttached( " WindowLocation " , typeof (Point),
typeof (WindowVisibilityHelper), new UIPropertyMetadata( new Point()));
private static WindowState GetWindowState(DependencyObject obj)
{
return (WindowState)obj.GetValue(WindowStateProperty);
}
private static void SetWindowState(DependencyObject obj, WindowState value)
{
obj.SetValue(WindowStateProperty, value);
}
private static readonly DependencyProperty WindowStateProperty =
DependencyProperty.RegisterAttached( " WindowState " , typeof (WindowState),
typeof (WindowVisibilityHelper), new UIPropertyMetadata(WindowState.Normal));
private static bool GetWindowIsShowInTaskBar(DependencyObject obj)
{
return ( bool )obj.GetValue(WindowIsShowInTaskBarProperty);
}
private static void SetWindowIsShowInTaskBar(DependencyObject obj, bool value)
{
obj.SetValue(WindowIsShowInTaskBarProperty, value);
}
private static readonly DependencyProperty WindowIsShowInTaskBarProperty =
DependencyProperty.RegisterAttached( " WindowIsShowInTaskBar " , typeof ( bool ),
typeof (WindowVisibilityHelper), new UIPropertyMetadata( true ));
}
