We Keep Coding

White window flashes when using UsesPerPixelOpacity to make a wpf window transparent

I create a transparent window with the following code here is the link
HwndSourceParameters p = new HwndSourceParameters("TestWindow", 100, 100);
p.UsesPerPixelOpacity = true;
p.WindowStyle |= 0x10000000; // WS_VISIBLE
HwndSource hwndSource = new HwndSource(p);
hwndSource.RootVisual = ellipse;
It works ok. But a white window always flashes before the ellipse appears and the size of white window is same with the parameters of HwndSourceParameters. It seems the code will render a white background window and then refresh it into transparent background and rootvisual. Anything wrong?

Prevent new window from going offscreen

If the MainWindow is too close to the edge of the screen, opening a New Window with relative positioning can go off screen.
I'd like to have it detect that it's off screen and reposition itself close to the edge, even overlapping the MainWindow. For Top, Bottom, Left and Right.
Example Project Source
https://www.dropbox.com/s/3r2guvssiakcz6f/WindowReposition.zip?dl=0
private Boolean IsWindowOpened = false;
// Info Button
//
private void buttonInfo_Click(object sender, RoutedEventArgs e)
{
MainWindow mainwindow = this;
// Start Info Window
InfoWindow info = new InfoWindow(mainwindow);
// Only Allow 1 Window Instance
if (IsWindowOpened) return;
info.ContentRendered += delegate { IsWindowOpened = true; };
info.Closed += delegate { IsWindowOpened = false; };
// Position Relative to MainWindow
info.Left = mainwindow.Left - 270;
info.Top = mainwindow.Top + 0;
// Open Info Window
info.Show();
}
Example of 1280x720 screen
MainWindow Center Screen
InfoWindow -270px Left, 0px Top
Off Screen
MainWindow Top Left of Screen
InfoWindow -270px Left, 0px Top
Reposition In Screen
MainWindow Top Left of Screen
InfoWindow -160px Left, 0px Top

To Place Dialog to Left
The quick-n-dirty way of doing this is to simply use Math.Max (i.e. the right-most value) to use the offset or 0, whichever is larger. Using System.Windows.Forms.Screen allows us to accommodate for multiple monitors.
private void btnInfoToLeft_Click(object sender, RoutedEventArgs e)
{
// Figure out which screen we're on
var allScreens = Screen.AllScreens.ToList();
var thisScreen = allScreens.SingleOrDefault(s => this.Left >= s.WorkingArea.Left && this.Left < s.WorkingArea.Right);
// Place dialog to left of window, but not past screen border
InfoWindow info= new InfoWindow();
info.Left = Math.Max(this.Left - info.Width - 10, thisScreen.WorkingArea.Left);
info.Top = Math.Max(this.Top - info.Height - 10, thisScreen.WorkingArea.Top);
info.Show();
}
Note that we use the Width of the dialog - it's ActualWidth will be 0 before it is shown on the screen.
To Place Dialog to Right
Similarly, we need to figure out the right-most boundaries of the screen, and account for the width of the main window and dialog, and take the Math.Min value (i.e. the left-most value).
private void btnInfoToRight_Click(object sender, RoutedEventArgs e)
{
// Figure out which screen we're on
var allScreens = Screen.AllScreens.ToList();
var thisScreen = allScreens.SingleOrDefault(s => this.Left >= s.WorkingArea.Left && this.Left < s.WorkingArea.Right);
// Place dialog to right of window, but not past screen border
InfoWindow info = new InfoWindow();
info.Left = Math.Min(this.Left + this.ActualWidth + 10, thisScreen.WorkingArea.Right - info.Width);
info.Top = Math.Min(this.Top + this.ActualHeight + 10, thisScreen.WorkingArea.Bottom - info.Height);
info.Show();
}
This time, we still use the Width of the dialog, but the ActualWidth of the main window, which will be the width after it has been drawn (and possibly resized).
In these examples, I've also placed the dialog above/below the main window. You can set the top of the dialog to be equal to the top of the main window, or play around to get it to line up with the bottom, etc., using this example as a guide.

There are no shortcuts for this kind of problem. You'll have to figure out the dimensions of the screen you're using, then adjust the position of the info window manually.
Take a look at this StackOverflow post: How to get the size of the current screen in WPF?

Set window's default location on a user screen

I have a windows Form Application.I want that when the application will run my window will always just on Taskbar and on the Right side means on the bottom-right of a user screen.It doesn't matter what is a user screen resolution is.So how can i do that ???

To build on MeNoMore's answer, to make your form show up in the bottom right corner of the primary screen (the screen with the task bar is usually the primary screen) you would set the following in the constructor of your form.
this.StartPosition = FormStartPosition.Manual;
this.Location = new Point(Screen.PrimaryScreen.WorkingArea.Width - this.Width,
Screen.PrimaryScreen.WorkingArea.Height - this.Height);

Other answers will not work. You have to do two things:
Set form's StartPosition to Manual
Set form's Location to what point you want
E.g. inside form's constructor:
StartPosition = FormStartPosition.Manual;
Location = new Point(Screen.PrimaryScreen.WorkingArea.Width - Width,
Screen.PrimaryScreen.WorkingArea.Height - Height);

You can try to use:
Form1.Location = new Point(x, y);
Take a look here

Use Form.StartPosition property

You use the WinTaskBar component for considering other factors on a desktop/screen.
[DllImport("SHELL32", CallingConvention = CallingConvention.StdCall)]
static extern uint SHAppBarMessage(int dwMessage, ref APPBARDATA pData);
It will let you control the positions (left & top).
Example:
formStartLeft = Screen.PrimaryScreen.WorkingArea.Width - this.Width;
formStartTop = taskBarHeight + Screen.PrimaryScreen.WorkingArea.Height;

Windows Vista Sidebar Equivalent

I'm trying to create an application that looks similar to the Windows Vista sidebar. There's an API that allows docking toolbars on the screen (AppBar), but it's not exactly what I'm looking for.
How can I attach a Form to the desktop and dock it to the side of the screen, but without preventing other windows from overlapping it?

With all the following options you get a Sidebar look-a-like (the code below is for a WPF Window):
//width of the sidebar
Width = 300;
//height (remember to add a reference to the System.Windows.Forms dll)
Height = System.Windows.Forms.Screen.PrimaryScreen.WorkingArea.Height;
//no window style means no border
WindowStyle = WindowStyle.None;
//not resizable
ResizeMode = ResizeMode.NoResize;
//allow a transparent sidebar
AllowsTransparency = true;
//change the color
Background = new SolidColorBrush(Colors.CadetBlue);
//set the opacity (how much transparent)
Opacity = 0.5d;
//offset from the top
Top = 0;
//offset from the left (calculated so it shows on the right side)
Left = SystemParameters.PrimaryScreenWidth - (double)GetValue(WidthProperty);
//set it the topmost window
Topmost = true;
//hide the icon from the taskbar
ShowInTaskbar = false;
Hope this helps!
Update:
Here's a similar solution for when you're using WindowsForms, altough with WPF you have much more possibilities! The differences are minor, everything explains itself. The last line I added hides the window taskbar-icon. Do not place the code in the constructor of the Form but in the Load-event, otherwise the Location will be wrong. In WPF this doesn't matter.
Width = 300;
Height = Screen.PrimaryScreen.Bounds.Height;
FormBorderStyle = FormBorderStyle.None;
BackColor = Color.CadetBlue;
Opacity = 0.5d;
Location = new Point(Screen.PrimaryScreen.WorkingArea.Width - Width, 0);
TopMost = true;
ShowInTaskbar = false;

How to fit Windows Form to any screen resolution?

I work on VS 2008 with C#. This below code does not work for me. My form was designed in 1024 x 768 resolution.
Our clients laptop is in 1366 x 768 resolution. To solve this problem, I set below code in Form Load event:
this.Location = new Point(0, 0);
this.Size = Screen.PrimaryScreen.WorkingArea.Size;
but the form does not resize as per screen resolution and bottom of my form gets hidden or cut or I miss the scroll bar.
Is there any way to solve this problem? Please show me the syntax.

Can't you start maximized?
Set the System.Windows.Forms.Form.WindowState property to FormWindowState.Maximized

If you want to set the form size programmatically, set the form's StartPosition property to Manual. Otherwise the form's own positioning and sizing algorithm will interfere with yours. This is why you are experiencing the problems mentioned in your question.
Example: Here is how I resize the form to a size half-way between its original size and the size of the screen's working area. I also center the form in the working area.
On computers with multiple monitors, the user probably expects the form to open on the same screen that the mouse pointer is on. We can get it with Screen.FromPoint(Cursor.Position).
public MainView()
{
InitializeComponent();
StartPosition = FormStartPosition.Manual;
Rectangle screen = Screen.FromPoint(Cursor.Position).WorkingArea;
int w = Width >= screen.Width ? screen.Width : (screen.Width + Width) / 2;
int h = Height >= screen.Height ? screen.Height : (screen.Height + Height) / 2;
Location = new Point(screen.Left + (screen.Width - w) / 2, screen.Top + (screen.Height - h) / 2);
Size = new Size(w, h);
}
Note that setting WindowState to FormWindowState.Maximized alone does not change the size of the restored window. So the window might look good as long as it is maximized, but when restored, the window size and location can still be wrong. So I suggest setting size and location even when you intend to open the window as maximized.

Probably a maximized Form helps, or you can do this manually upon form load:
Code Block
this.Location = new Point(0, 0);
this.Size = Screen.PrimaryScreen.WorkingArea.Size;
And then, play with anchoring, so the child controls inside your form automatically fit in your form's new size.

Set the form property to open in maximized state.
this.WindowState = FormWindowState.Maximized;

int h = Screen.PrimaryScreen.WorkingArea.Height;
int w = Screen.PrimaryScreen.WorkingArea.Width;
this.ClientSize = new Size(w , h);

You can simply set the window state
this.WindowState = System.Windows.Forms.FormWindowState.Maximized;

simply set Autoscroll = true for ur windows form.. (its not good solution but helpful)..
try for panel also(Autoscroll property = true)

You can always tell the window to start in maximized... it should give you the same result... Like this: this.WindowState = FormWindowState.Maximized;
P.S. You could also try (and I'm not recommending this) to subtract the taskbar height.