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Hide desktop icons from C# WPF

I need a solution to show/hide desktop icons programmatically with C# WPF
Now one possible way is to change the this registry value:
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced
HideIcons = 1
But to make it take effect I need to restart Explorer.exe which is not an option.
Cause my program runs on desktop background. and killing Explorer kills the program and I have restart it.
I also tried this:
Stackoverflow Link
But it didn't work on Windows 10
So, is there any other way to do it? Please Help !

Create Class Library add this code in it
and add namespace System.Runtime.InteropServices
[DllImport("user32.dll", SetLastError = true)]
static extern IntPtr FindWindow(string lpClassName, string lpWindowName);
[DllImport("user32.dll", SetLastError = true)]
static extern IntPtr GetWindow(IntPtr hWnd, GetWindow_Cmd uCmd);
enum GetWindow_Cmd : uint
{
GW_HWNDFIRST = 0,
GW_HWNDLAST = 1,
GW_HWNDNEXT = 2,
GW_HWNDPREV = 3,
GW_OWNER = 4,
GW_CHILD = 5,
GW_ENABLEDPOPUP = 6
}
[DllImport("user32.dll", CharSet = CharSet.Auto)]
static extern IntPtr SendMessage(IntPtr hWnd, UInt32 Msg, IntPtr wParam, IntPtr lParam);
private const int WM_COMMAND = 0x111;
public static void ToggleDesktopIcons()
{
var toggleDesktopCommand = new IntPtr(0x7402);
IntPtr hWnd = GetWindow(FindWindow("Progman", "Program Manager"), GetWindow_Cmd.GW_CHILD);
SendMessage(hWnd, WM_COMMAND, toggleDesktopCommand, IntPtr.Zero);
}
[return: MarshalAs(UnmanagedType.Bool)]
[DllImport("user32.dll", SetLastError = true)]
private static extern bool GetWindowInfo(IntPtr hwnd, ref WINDOWINFO pwi);
[StructLayout(LayoutKind.Sequential)]
public struct RECT
{
private int _Left;
private int _Top;
private int _Right;
private int _Bottom;
}
[StructLayout(LayoutKind.Sequential)]
struct WINDOWINFO
{
public uint cbSize;
public RECT rcWindow;
public RECT rcClient;
public uint dwStyle;
public uint dwExStyle;
public uint dwWindowStatus;
public uint cxWindowBorders;
public uint cyWindowBorders;
public ushort atomWindowType;
public ushort wCreatorVersion;
public WINDOWINFO(Boolean? filler)
: this() // Allows automatic initialization of "cbSize" with "new WINDOWINFO(null/true/false)".
{
cbSize = (UInt32)(Marshal.SizeOf(typeof(WINDOWINFO)));
}
}
public static bool IsVisible()
{
IntPtr hWnd = GetWindow(GetWindow(FindWindow("Progman", "Program Manager"), GetWindow_Cmd.GW_CHILD), GetWindow_Cmd.GW_CHILD);
WINDOWINFO info = new WINDOWINFO();
info.cbSize = (uint)Marshal.SizeOf(info);
GetWindowInfo(hWnd, ref info);
return (info.dwStyle & 0x10000000) == 0x10000000;
}
add this dll reference to your project..
and call dllClass_name.ToggleDesktopIcon();

How to check whether application is running fullscreen mode on any screen?

I'd like to check, if any screen hosts application in fullscreen mode. I have solution only for one screen which is code copied from here: [WPF] [C#] How-to : Detect if another application is running in full screen mode. This solution is based on
[DllImport("user32.dll")]
private static extern IntPtr GetForegroundWindow();
which gathers only active window handle. The problem is, I have two screens. I've searched many sites but none of them answers my question. It is not about capturing screenshot, which is simple and doesn't rely on P/Invoke.
Is this possible?

No ready-to-use solution here, but let's see..
Get list of all displayed windows and check positions and sizes of those windows - possible, lots of tools does it, many articles on that, I'll skip this one. Then, you can call MonitorFromWindow for each or some windows and compare window dimensions&position against monitor info. If windowpos ~= 0,0 and windowsize ~= monitorresolution you could assume that this window is in fullscreen mode.
On the other hand, if already having a list of all HWNDs, then why not just Query the window for its placement and check the WINDOWPLACEMENT.showCmd for SW_MAXIMIZE/SW_SHOWMAXIMIZED flags. That won't tell you which monitor is it, but should tell you at least if the window is maximized and if it's enough for you..
I don't know how fast/slow would it be to do it like that, but, yes, it seems possible.

You could use EnumWindows in conjunction with Screen.FromHandle. And maybe GetWindowRect() for calculations.
Something like (pseudo-code!):
//------------------------------
//this sample code is taken from http://pinvoke.net/default.aspx/user32/EnumWindows.html
public delegate bool EnumedWindow(IntPtr handleWindow, ArrayList handles);
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool EnumWindows(EnumedWindow lpEnumFunc, ArrayList lParam);
public static ArrayList GetWindows()
{
ArrayList windowHandles = new ArrayList();
EnumedWindow callBackPtr = GetWindowHandle;
EnumWindows(callBackPtr, windowHandles);
return windowHandles;
}
private static bool GetWindowHandle(IntPtr windowHandle, ArrayList windowHandles)
{
windowHandles.Add(windowHandle);
return true;
}
//------------------------------
[DllImport("user32.dll")]
private static extern bool GetWindowRect(IntPtr hWnd, [In,Out] ref Rect rect);
[StructLayout(LayoutKind.Sequential)]
private struct Rect
{
public int Left;
public int Top;
public int Right;
public int Bottom;
}
static void Main() {
foreach(IntPtr handle in GetWindows())
{
Screen scr = Screen.FromHandle(handle);
if(IsFullscreen(handle, scr))
{
// the window is fullscreen...
}
}
}
private bool IsFullscreen(IntPtr wndHandle, Screen screen)
{
Rect r = new Rect();
GetWindowRect(wndHandle, ref r);
return new Rectangle(r.Left, r.Top, r.Right-r.Left, r.Bottom-r.Top)
.Contains(screen.Bounds);
}

I wrote piece of code which is working:
namespace EnumWnd
{
using System;
using System.Runtime.InteropServices;
using System.Text;
[StructLayout(LayoutKind.Sequential)]
public struct Rect
{
public int Left;
public int Top;
public int Right;
public int Bottom;
}
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
internal struct MonitorInfoEx
{
public int cbSize;
public Rect rcMonitor;
public Rect rcWork;
public UInt32 dwFlags;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 32)] public string szDeviceName;
}
internal class Program
{
[DllImport("user32.dll")]
public static extern bool GetWindowRect(IntPtr hWnd, out Rect lpRect);
[DllImport("user32.dll", CharSet = CharSet.Unicode)]
protected static extern int GetWindowText(IntPtr hWnd, StringBuilder strText, int maxCount);
[DllImport("user32.dll", CharSet = CharSet.Unicode)]
protected static extern int GetWindowTextLength(IntPtr hWnd);
[DllImport("user32.dll")]
protected static extern bool EnumWindows(EnumWindowsProc enumProc, IntPtr lParam);
[DllImport("user32.dll")]
protected static extern bool IsWindowVisible(IntPtr hWnd);
[DllImport("User32")]
public static extern IntPtr MonitorFromWindow(IntPtr hWnd, int dwFlags);
[DllImport("user32", EntryPoint = "GetMonitorInfo", CharSet = CharSet.Auto,
SetLastError = true)]
internal static extern bool GetMonitorInfoEx(IntPtr hMonitor, ref MonitorInfoEx lpmi);
protected static bool EnumTheWindows(IntPtr hWnd, IntPtr lParam)
{
const int MONITOR_DEFAULTTOPRIMARY = 1;
var mi = new MonitorInfoEx();
mi.cbSize = Marshal.SizeOf(mi);
GetMonitorInfoEx(MonitorFromWindow(hWnd, MONITOR_DEFAULTTOPRIMARY), ref mi);
Rect appBounds;
GetWindowRect(hWnd, out appBounds);
int size = GetWindowTextLength(hWnd);
if (size++ > 0 && IsWindowVisible(hWnd))
{
var sb = new StringBuilder(size);
GetWindowText(hWnd, sb, size);
if (sb.Length > 20)
{
sb.Remove(20, sb.Length - 20);
}
int windowHeight = appBounds.Right - appBounds.Left;
int windowWidth = appBounds.Bottom - appBounds.Top;
int monitorHeight = mi.rcMonitor.Right - mi.rcMonitor.Left;
int monitorWidth = mi.rcMonitor.Bottom - mi.rcMonitor.Top;
bool fullScreen = (windowHeight == monitorHeight) && (windowWidth == monitorWidth);
sb.AppendFormat(" Wnd:({0} | {1}) Mtr:({2} | {3} | Name: {4}) - {5}", windowWidth, windowHeight, monitorWidth, monitorHeight, mi.szDeviceName, fullScreen);
Console.WriteLine(sb.ToString());
}
return true;
}
private static void Main()
{
while (true)
{
EnumWindows(EnumTheWindows, IntPtr.Zero);
Console.ReadKey();
Console.Clear();
}
}
protected delegate bool EnumWindowsProc(IntPtr hWnd, IntPtr lParam);
}
}
Thanks for #SamAxe and #quetzalcoatl for providing me useful tips.

C# and partially working SendMessage?

I've tried to send text messages to various applications in Windows 7 (eg. Notepad++, Notepad etc.). SendMessage is working fine for Notepad but not for Notepad++.
If i'm sending text to Notepad everything appears fine, whole text and i'm getting 1 as return from SendMessage method. But for Notepad++ only first letter appears and method SendMessage is returning 0, however Marshal.GetLastWin32Error() is not returning any error (result 0)?
Here's the code:
GUITHREADINFO gti = new GUITHREADINFO();
IntPtr hWnd = GetForegroundWindow();
uint processId;
uint activeThreadId = GetWindowThreadProcessId(hWnd, out processId);
if (GetInfo(activeThreadId, out gti))
{
int EM_REPLACESEL = 0x00C2;
int error = Marshal.GetLastWin32Error();
int result = SendMessageW(gti.hwndCaret, EM_REPLACESEL, -1, passed);//3rd param doesn't change anything
error = Marshal.GetLastWin32Error();
}
WinAPI functions and GetInfo method as long with required structures are defined as:
[DllImport("User32.dll", EntryPoint = "SendMessageW", SetLastError = true, CharSet = CharSet.Unicode)]
public static extern int SendMessageW(IntPtr hWnd, int uMsg, int wParam, string lParam);
[DllImport("user32.dll")]
static extern IntPtr GetForegroundWindow();
[DllImport("user32.dll", SetLastError = true)]
static extern uint GetWindowThreadProcessId(IntPtr hWnd, out uint lpdwProcessId);
//"Borrowed" code
public static bool GetInfo(uint hwnd, out GUITHREADINFO lpgui)
{
uint lpdwProcessId;
uint threadId = GetWindowThreadProcessId(hwnd, out lpdwProcessId);
lpgui = new GUITHREADINFO();
lpgui.cbSize = Marshal.SizeOf(lpgui);
return GetGUIThreadInfo(threadId, ref lpgui);
}
[StructLayout(LayoutKind.Sequential)]
public struct RECT
{
public int iLeft;
public int iTop;
public int iRight;
public int iBottom;
}
[StructLayout(LayoutKind.Sequential)]
public struct GUITHREADINFO
{
public int cbSize;
public int flags;
public IntPtr hwndActive;
public IntPtr hwndFocus;
public IntPtr hwndCapture;
public IntPtr hwndMenuOwner;
public IntPtr hwndMoveSize;
public IntPtr hwndCaret;
public RECT rectCaret;
}
So well i wonder what should i do to fix it so it would work (fully) for all windows not only for edit control in Notepad?

HDMI TV sometimes not detected in windows 7? Possible to invoke Detect in code?

i have a standalone public kiosk pc that startups automatically everyday. It is connected to a HD TV and sometimes it is not detected. i have to personally go down to the PC, go to Screen Resolution and press Detect which it works.
my question is how do i know if the monitor i want it to display is connected properly in code?
thanks

I did manage to find some code on the MSDN site where a user is using code to determine which type of monitor is connected. I hope this may be a good starting point for you.
using System;
using System.Runtime.InteropServices;
using System.Windows;
using System.Windows.Interop;
namespace CRT
{
/// <summary>
/// Interaction logic for Window1.xaml
/// </summary>
public partial class Window1 : Window
{
public class NativeMethods
{
[DllImport("user32.dll", EntryPoint = "MonitorFromWindow", SetLastError = true)]
public static extern IntPtr MonitorFromWindow(
[In] IntPtr hwnd, uint dwFlags);
[DllImport("dxva2.dll", EntryPoint = "GetNumberOfPhysicalMonitorsFromHMONITOR", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool GetNumberOfPhysicalMonitorsFromHMONITOR(
IntPtr hMonitor, ref uint pdwNumberOfPhysicalMonitors);
[DllImport("dxva2.dll", EntryPoint = "GetPhysicalMonitorsFromHMONITOR", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool GetPhysicalMonitorsFromHMONITOR(
IntPtr hMonitor,
uint dwPhysicalMonitorArraySize,
[Out] NativeStructures.PHYSICAL_MONITOR[] pPhysicalMonitorArray);
[DllImport("dxva2.dll", EntryPoint = "DestroyPhysicalMonitors", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool DestroyPhysicalMonitors(
uint dwPhysicalMonitorArraySize, [Out] NativeStructures.PHYSICAL_MONITOR[] pPhysicalMonitorArray);
[DllImport("dxva2.dll", EntryPoint = "GetMonitorTechnologyType", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool GetMonitorTechnologyType(
IntPtr hMonitor, ref NativeStructures.MC_DISPLAY_TECHNOLOGY_TYPE pdtyDisplayTechnologyType);
[DllImport("dxva2.dll", EntryPoint = "GetMonitorCapabilities", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool GetMonitorCapabilities(
IntPtr hMonitor, ref uint pdwMonitorCapabilities, ref uint pdwSupportedColorTemperatures);
}
public class NativeConstants
{
public const int MONITOR_DEFAULTTOPRIMARY = 1;
public const int MONITOR_DEFAULTTONEAREST = 2;
public const int MONITOR_DEFAULTTONULL = 0;
}
public class NativeStructures
{
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public struct PHYSICAL_MONITOR
{
public IntPtr hPhysicalMonitor;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 128)] public string szPhysicalMonitorDescription;
}
public enum MC_DISPLAY_TECHNOLOGY_TYPE
{
MC_SHADOW_MASK_CATHODE_RAY_TUBE,
MC_APERTURE_GRILL_CATHODE_RAY_TUBE,
MC_THIN_FILM_TRANSISTOR,
MC_LIQUID_CRYSTAL_ON_SILICON,
MC_PLASMA,
MC_ORGANIC_LIGHT_EMITTING_DIODE,
MC_ELECTROLUMINESCENT,
MC_MICROELECTROMECHANICAL,
MC_FIELD_EMISSION_DEVICE,
}
}
public Window1() { InitializeComponent(); }
private void Button_Click(object sender, RoutedEventArgs e)
{
WindowInteropHelper helper = new WindowInteropHelper(this);
IntPtr hMonitor = NativeMethods.MonitorFromWindow(helper.Handle, NativeConstants.MONITOR_DEFAULTTOPRIMARY);
int lastWin32Error = Marshal.GetLastWin32Error();
uint pdwNumberOfPhysicalMonitors = 0u;
bool numberOfPhysicalMonitorsFromHmonitor = NativeMethods.GetNumberOfPhysicalMonitorsFromHMONITOR(
hMonitor, ref pdwNumberOfPhysicalMonitors);
lastWin32Error = Marshal.GetLastWin32Error();
NativeStructures.PHYSICAL_MONITOR[] pPhysicalMonitorArray =
new NativeStructures.PHYSICAL_MONITOR[pdwNumberOfPhysicalMonitors];
bool physicalMonitorsFromHmonitor = NativeMethods.GetPhysicalMonitorsFromHMONITOR(
hMonitor, pdwNumberOfPhysicalMonitors, pPhysicalMonitorArray);
lastWin32Error = Marshal.GetLastWin32Error();
uint pdwMonitorCapabilities = 0u;
uint pdwSupportedColorTemperatures = 0u;
var monitorCapabilities = NativeMethods.GetMonitorCapabilities(
pPhysicalMonitorArray[0].hPhysicalMonitor, ref pdwMonitorCapabilities, ref pdwSupportedColorTemperatures);
lastWin32Error = Marshal.GetLastWin32Error();
NativeStructures.MC_DISPLAY_TECHNOLOGY_TYPE type =
NativeStructures.MC_DISPLAY_TECHNOLOGY_TYPE.MC_SHADOW_MASK_CATHODE_RAY_TUBE;
var monitorTechnologyType = NativeMethods.GetMonitorTechnologyType(
pPhysicalMonitorArray[0].hPhysicalMonitor, ref type);
lastWin32Error = Marshal.GetLastWin32Error();
var destroyPhysicalMonitors = NativeMethods.DestroyPhysicalMonitors(
pdwNumberOfPhysicalMonitors, pPhysicalMonitorArray);
lastWin32Error = Marshal.GetLastWin32Error();
this.lbl.Content = type;
}
}
}

How to use Win32 GetMonitorInfo() in .NET c#?

I have to implement a feature where the last position of the window is saved. When the application starts up this position needs to be obtained and restored.
Now it could be that a second monitor is dismantled. If the last position is on a now non-visible monitor (in other words the saved coordinates are outside the visible coordinates), this case should be caught and the coordinates shall be set to the default rather than last position.
In order to retrieve the information about monitors I need to use Win32. It is not easy for me to make this work.
I have created a Helper CLass:
public static class DisplayHelper
{
private const int MONITOR_DEFAULTTONEAREST = 2;
[DllImport("user32.dll", CharSet = CharSet.Auto, ExactSpelling = true)]
public static extern int GetSystemMetrics(int nIndex);
[DllImport("user32.dll", CharSet = CharSet.Auto, ExactSpelling = true)]
private static extern UInt32 MonitorFromPoint(Point pt, UInt32 dwFlags);
[DllImport("user32.dll", CharSet = CharSet.Auto, ExactSpelling = true)]
private static extern bool GetMonitorInfo(UInt32 monitorHandle, ref MonitorInfo mInfo);
public static void GetMonitorInfoNow(MonitorInfo mi, Point pt)
{
UInt32 mh = MonitorFromPoint(pt, 0);
mi.cbSize = (UInt32)System.Runtime.InteropServices.Marshal.SizeOf(typeof(MonitorInfo));
mi.dwFlags = 0;
bool result = GetMonitorInfo(mh, ref mi);
}
}
And these are my attempts to create the MonitorInfo and Rect classes:
[StructLayout(LayoutKind.Sequential)]
public class MonitorInfo
{
public UInt32 cbSize;
public Rectangle2 rcMonitor;
public Rectangle2 rcWork;
public UInt32 dwFlags;
public MonitorInfo()
{
rcMonitor = new Rectangle2();
rcWork = new Rectangle2();
cbSize = (UInt32)System.Runtime.InteropServices.Marshal.SizeOf(typeof(MonitorInfo));
dwFlags = 0;
}
}
[StructLayout(LayoutKind.Sequential)]
public class Rectangle2
{
public UInt64 left;
public UInt64 top;
public UInt64 right;
public UInt64 bottom;
public Rectangle2()
{
left = 0;
top = 0;
right = 0;
bottom = 0;
}
}
I am using this code like this to obtain the visible monitors:
//80 means it counts only visible display monitors.
int lcdNr = DisplayHelper.GetSystemMetrics(80);
var point = new System.Drawing.Point((int) workSpaceWindow.Left, (int) workSpaceWindow.Top);
MonitorInfo monitorInfo = new MonitorInfo();
DisplayHelper.GetMonitorInfoNow(monitorInfo, point);
The last method throws an exception when trying to execute
bool result = GetMonitorInfo(mh, ref mi);
Any suggestions what I need to do to fix this?

Rather than calling a native API, you should use System.Windows.Forms.Screen. It should have everything you need, and be much easier to use.
Screen.FromPoint is the managed equivalent of your GetMonitorInfoNow function with the MONITOR_DEFAULTTONEAREST option. I just noticed you aren't using that option, so you may have to write your own or use the correct P/Invoke signatures.
Writing your own should be fairly simple, if you just reference System.Drawing and System.Windows.Forms. Both of these should work:
static Screen ScreenFromPoint1(Point p)
{
System.Drawing.Point pt = new System.Drawing.Point((int)p.X, (int)p.Y);
return Screen.AllScreens
.Where(scr => scr.Bounds.Contains(pt))
.FirstOrDefault();
}
static Screen ScreenFromPoint2(Point p)
{
System.Drawing.Point pt = new System.Drawing.Point((int)p.X, (int)p.Y);
var scr = Screen.FromPoint(pt);
return scr.Bounds.Contains(pt) ? scr : null;
}
If you prefer to make the Win32 calls yourself, the proper P/Invoke signatures (i.e. what you'd get from decompiling the .Net DLL) for the functions you need to call are:
[DllImport("User32.dll", CharSet=CharSet.Auto)]
public static extern bool GetMonitorInfo(HandleRef hmonitor, [In, Out]MONITORINFOEX info);
[DllImport("User32.dll", ExactSpelling=true)]
public static extern IntPtr MonitorFromPoint(POINTSTRUCT pt, int flags);
[StructLayout(LayoutKind.Sequential,CharSet=CharSet.Auto, Pack=4)]
public class MONITORINFOEX {
public int cbSize = Marshal.SizeOf(typeof(MONITORINFOEX));
public RECT rcMonitor = new RECT();
public RECT rcWork = new RECT();
public int dwFlags = 0;
[MarshalAs(UnmanagedType.ByValArray, SizeConst=32)]
public char[] szDevice = new char[32];
}
[StructLayout(LayoutKind.Sequential)]
public struct POINTSTRUCT {
public int x;
public int y;
public POINTSTRUCT(int x, int y) {
this.x = x;
this.y = y;
}
}
[StructLayout(LayoutKind.Sequential)]
public struct RECT {
public int left;
public int top;
public int right;
public int bottom;
}

I found one different is
public static extern bool GetMonitorInfo(IntPtr hMonitor, [In,Out] MONITORINFO lpmi) and
public static extern bool GetMonitorInfo(IntPtr hMonitor, ref MONITORINFO lpmi)
In my case, the ref keywork made the function always return false.
But if remove this keyword or usr [In,Out], it work.
More info about ref vs. [In,Out] on This.

Your Rectangle2 should use Int32 or just int, not Int64. More information can be found here.
Also it needs to be a struct, not a class. Same goes for your MonitorInfo class (it should be a struct). I'd recommend trying the version from the link above, or compare them with your versions.

Since you are using the MonitorInfo class, not a struct, you must specify the [Out] attribute and not use ref in order for the marshaler to update your class correctly.
[DllImport("user32", CharSet = CharSet.Auto, SetLastError = true)]
internal static extern bool GetMonitorInfo(
IntPtr hmonitor,
[In, Out] MonitorInfo info);
You can also go to using structure and ref, then it will look like this:
[DllImport("user32", CharSet = CharSet.Auto, SetLastError = true)]
internal static extern bool GetMonitorInfo(
IntPtr hmonitor,
ref MonitorInfoEx info);
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto, Pack = 4)]
internal struct MonitorInfoEx
{
public uint cbSize;
public RECT rcMonitor;
public RECT rcWork;
public uint dwFlags;
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 32)]
public char[] szDevice;
}
var info = new MonitorInfoEx
{
cbSize = (uint)Marshal.SizeOf(typeof(MonitorInfoEx)),
};
GetMonitorInfo(hDesktop, ref info);