WPF中的无边框透明窗体，由于没有边并且透明，窗体无法进行缩放操作，今天来讲解如何解决这个问题。
先说一下思路，我们先手为该窗体添加4个边，4个角用于缩放操作，然后再为他们写事件，完成拖放操作。
xaml代码：
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<Window
x:Class="WpfResizeWindow.Window1" Title="Window1"
Height="300"
Width="300"
WindowStyle="None"
AllowsTransparency="True">
<Grid>
<Grid.RowDefinitions>
<RowDefinition
Height="4"/>
<RowDefinition/>
<RowDefinition
Height="4"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition
Width="4"/>
<ColumnDefinition/>
<ColumnDefinition
Width="4"/>
</Grid.ColumnDefinitions>
<Rectangle
Name="ResizeTopLeft"
Fill="Black"
Grid.Row="0"
Grid.Column="0"
MouseMove="ResizePressed"
MouseDown="ResizePressed"/>
<Rectangle
Name="ResizeTop"
Fill="Black"
Grid.Row="0"
Grid.Column="1"
MouseMove="ResizePressed"
MouseDown="ResizePressed"/>
<Rectangle
Name="ResizeTopRight"
Fill="Black"
Grid.Row="0"
Grid.Column="2"
MouseMove="ResizePressed"
MouseDown="ResizePressed"/>
<Rectangle
Name="ResizeLeft"
Fill="Black"
Grid.Row="1"
Grid.Column="0"
MouseMove="ResizePressed"
MouseDown="ResizePressed"/>
<Rectangle
Name="ResizeRight"
Fill="Black"
Grid.Row="1"
Grid.Column="3"
MouseMove="ResizePressed"
MouseDown="ResizePressed"/>
<Rectangle
Name="ResizeBottomLeft"
Fill="Black"
Grid.Row="3"
Grid.Column="0"
MouseMove="ResizePressed"
MouseDown="ResizePressed"/>
<Rectangle
Name="ResizeBottom"
Fill="Black"
Grid.Row="3"
Grid.Column="1"
MouseMove="ResizePressed"
MouseDown="ResizePressed"/>
<Rectangle
Name="ResizeBottomRight"
Fill="Black"
Grid.Row="3"
Grid.Column="2"
MouseMove="ResizePressed"
MouseDown="ResizePressed"/>
</Grid>
</Window> |
cs代码：
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public
partial class
Window1 : Window { private
const int
WM_SYSCOMMAND = 0x112; private
HwndSource _HwndSource; private
Dictionary<ResizeDirection, Cursor> cursors = new
Dictionary<ResizeDirection, Cursor> {
{ResizeDirection.Top, Cursors.SizeNS},
{ResizeDirection.Bottom, Cursors.SizeNS},
{ResizeDirection.Left, Cursors.SizeWE},
{ResizeDirection.Right, Cursors.SizeWE},
{ResizeDirection.TopLeft, Cursors.SizeNWSE},
{ResizeDirection.BottomRight, Cursors.SizeNWSE},
{ResizeDirection.TopRight, Cursors.SizeNESW},
{ResizeDirection.BottomLeft, Cursors.SizeNESW}
};
private
enum ResizeDirection
{
Left = 1,
Right = 2,
Top = 3,
TopLeft = 4,
TopRight = 5,
Bottom = 6,
BottomLeft = 7,
BottomRight = 8, }
[DllImport("user32.dll", CharSet = CharSet.Auto)]
private
static extern
IntPtr SendMessage(IntPtr hWnd, uint
Msg, IntPtr wParam, IntPtr lParam); public
Window1() {
InitializeComponent();
this.SourceInitialized +=
delegate(object
sender, EventArgs e)
{
this._HwndSource = PresentationSource.FromVisual((Visual)sender)
as HwndSource;
};
this.MouseMove +=
new MouseEventHandler(Window_MouseMove);
}
void
Window_MouseMove(object
sender, MouseEventArgs e) {
if (Mouse.LeftButton != MouseButtonState.Pressed)
{
FrameworkElement element = e.OriginalSource as
FrameworkElement;
if (element !=
null && !element.Name.Contains("Resize"))
this.Cursor = Cursors.Arrow;
} }
private
void ResizePressed(object
sender, MouseEventArgs e) {
FrameworkElement element = sender as
FrameworkElement;
ResizeDirection direction = (ResizeDirection)Enum.Parse(typeof(ResizeDirection), element.Name.Replace("Resize",
""));
this.Cursor = cursors[direction];
if (e.LeftButton == MouseButtonState.Pressed)
ResizeWindow(direction); }
private
void ResizeWindow(ResizeDirection direction)
{
SendMessage(_HwndSource.Handle, WM_SYSCOMMAND, (IntPtr)(61440 + direction), IntPtr.Zero);
}
} |
从代码可以看出，先注册4个边和4个角的MouseMove和MouseDown事件，鼠标移动到拖放内容上时，判断鼠标悬停在那个边上，改变鼠标指针变成相应对象，判断鼠标是否按下，如果按下了，则发送Win32消息，进行拖放操作，从代码中可以看出来最终的拖放还是使用Win32 api来实现，因为，如果完全用wpf的事件进行拖放的话，实在是太慢了。