We Keep Coding

Screen Capture program copies more than selected area

I followed Huw Collingbourne program in creating a screen capture program with C#. However, I noticed a couple of weird items, and whether I use his created program or my modified program does the same. Specifically I created a program that opens a window that allows you to capture the area.
I think it has to do with sittings on my computer, but need to know how to anticipate and fix this if others are going to use my screen capture program!
If my display for windows 10 is set to 100% I get a little more than the selected window and if I set display to 125% text then I get a lot of the selected area. Leaving at default size I should be 555, 484 in size. but I capture much larger.
public partial class Form1 : Form
{
//https://learn.microsoft.com/en-us/windows/desktop/api/winuser/nf-winuser-getwindowrect
[DllImport("user32.dll")]
private static extern IntPtr GetForegroundWindow();
[DllImport("user32.dll")]
private static extern IntPtr GetDesktopWindow();
[DllImport("user32.dll")]
private static extern bool GetWindowRect(IntPtr hWnd, ref Rectangle lpRect);
//ICON info
//https://learn.microsoft.com/en-us/windows/desktop/api/winuser/nf-winuser-getcursorinfo
[DllImport("user32.dll")]
private static extern bool GetIconInfo(IntPtr hIcon, out ICONINFO piconinfo);
[DllImport("user32.dll")]
private static extern bool GetCursorInfo(out CURSORINFO pci);
public struct POINT
{
public Int32 x;
public Int32 y;
}
public struct ICONINFO
{
public bool fIcon;
public Int32 xHotspot;
public Int32 yHotspot;
public IntPtr hbmMask;
public IntPtr hbmColor;
}
public struct CURSORINFO
{
public Int32 cbSize;
public Int32 flags;
public IntPtr hCursor;
public Point ptScreenPos;
}
GrabRegionForm grabForm;
public void GrabRect(Rectangle rect)
{
int rectWidth = rect.Width - rect.Left;
int rectHeight = rect.Height - rect.Top;
Bitmap bm = new Bitmap(rectWidth, rectHeight);
Graphics g = Graphics.FromImage(bm);
g.CopyFromScreen(rect.Left, rect.Top, 0, 0, new Size(rectWidth, rectHeight));
DrawMousePointer(g, Cursor.Position.X - rect.Left, Cursor.Position.Y - rect.Top);
this.pb_screengrab.Image = bm;
Clipboard.SetImage(bm);
}
}
public partial class GrabRegionForm : Form
{
public Rectangle formRect;
private Form1 mainForm;
[DllImport("user32.dll")]
public static extern bool ReleaseCapture();
[DllImport("user32.dll")]
public static extern int SendMessage(IntPtr hWnd, int Msg, int wParam, int lParam);
private void buttonOK_Click(object sender, EventArgs e)
{
formRect = new Rectangle(this.Left, this.Top, this.Left + this.Width, this.Top + this.Height);
this.Hide();
mainForm.GrabRect(formRect);
Close();
}
}
ScreenGrab with Display at 100%
ScreenGrab with Display at 125%
Area showing capture window
Area Actually Captured

IF using earlier than 4.7 and not windows 10 follow Jimi's examples and ensure you sign out and back into windows.
From Jimi https://stackoverflow.com/users/7444103/jimi
How to configure an app to run correctly on a machine with a high DPI setting How to configure an app to run correctly on a machine with a high DPI setting (e.g. 150%)?
From Jimi https://stackoverflow.com/users/7444103/jimi
Using SetWindowPos with multiple monitors Using SetWindowPos with multiple monitors
If I target my app for windows 10 Only it is incredibly simple now.
Microsoft made it even easier to change DPI settings with using 4.7 if using Windows 10.
https://learn.microsoft.com/en-us/dotnet/framework/winforms/high-dpi-support-in-windows-forms
Declare compatibility with Windows 10.
Then add the following to the app.manifest file in the XML under the commend for Windows 10 compatibility.
supportedOS Id="{8e0f7a12-bfb3-4fe8-b9a5-48fd50a15a9a}"
Enable per-monitor DPI awareness in the app.config file.
Windows Forms introduces a new element to support new features and customizations added starting with the .NET Framework 4.7. To take advantage of the new features that support high DPI, add the following to your application configuration file.
Go to the XML line for System.Windows.Forms.ApplicationConfigurationSection
add key="DpiAwareness" value="PerMonitorV2"

Windows screensaver in C# using WPF crashing during preview mode

I have just started to learn C# and am trying to write a screensaver. My App.xaml.cs contains the following code for when the /p argument is used:
else if (arg1 == "/p")
{
if (e.Args[1] == null)
{
System.Windows.Forms.MessageBox.Show("Invalid or missing window handle.");
System.Windows.Application.Current.Shutdown();
}
IntPtr previewHandle = new IntPtr(long.Parse(e.Args[1]));
System.Windows.Application.Current.Run(new MainWindow(previewHandle));
}
Then in my MainWindow.xaml.cs, this construct handles the preview call:
public MainWindow(IntPtr previewHandle)
{
App.Current.Properties["isPreviewMode"] = true;
App.Current.Properties["previewHandle"] = previewHandle;
InitializeComponent();
}
After this, it crashes. In my MainWindow.xaml I have Loaded="MainWindow_Loaded".
In MainWindows.xaml.cs this is MainWindow_Loaded:
private void MainWindow_Loaded(object sender, RoutedEventArgs e)
{
if ((bool)App.Current.Properties["isPreviewMode"])
{
IntPtr myHandle = new WindowInteropHelper(this).Handle;
SetParent(myHandle, (IntPtr)App.Current.Properties["previewHandle"]);
SetWindowLong(myHandle, -16, new IntPtr(GetWindowLong(myHandle, -16) | 0x40000000));
Rectangle ParentRect;
GetClientRect((IntPtr)App.Current.Properties["previewHandle"], out ParentRect);
this.Top = ParentRect.X;
this.Left = ParentRect.Y;
this.Height = ParentRect.Height;
this.Width = ParentRect.Width;
}
ssimage.Source = new BitmapImage(new Uri("pack://application:,,,/Resources/EmbeddedImage.PNG"));
}
[DllImport("user32.dll")]
static extern IntPtr SetParent(IntPtr hWndChild, IntPtr hWndNewParent);
[DllImport("user32.dll")]
static extern int SetWindowLong(IntPtr hWnd, int nIndex, IntPtr dwNewLong);
[DllImport("user32.dll", SetLastError = true)]
static extern int GetWindowLong(IntPtr hWnd, int nIndex);
[DllImport("user32.dll")]
static extern bool GetClientRect(IntPtr hWnd, out Rectangle lpRect);
I have other code in the App.xaml.cs to handle changing the images on a timer and other code in MainWindow.xaml.cs to handle mouse movement, clicks and keypresses. Everything works fine when running the screensaver normally. It is just the preview that fails. What am I doing wrong?

To my knowledge, WPF does not allow you to retarget the window handle, so performing screensaver previews in WPF using your technique is impossible.
However, there is a workaround: if you configure WPF to render to a bitmap target (see RenderTargetBitmap), you could then blit that bitmap onto the desired destination window handle - but this would involve an unholy mix of GDI and WPF and probably have awful runtime performance; I doubt it would be worth the effort.

What I ended up doing was using the WPF windows to display when the screensaver runs normally in full screen with /s. I created a new regular windows form previewForm.cs with a picturebox to use for the preview. That works fine and there is no performance issues. I assume the picturebox is using GDI.
This is my modified App.xaml.cs for handling the /p argument:
else if (arg1 == "/p")
{
if (e.Args[1] == null)
{
System.Windows.Forms.MessageBox.Show("Invalid or missing window handle.");
System.Windows.Application.Current.Shutdown();
}
IntPtr previewHandle = new IntPtr(long.Parse(e.Args[1]));
pw = new previewForm(previewHandle);
GetImages();
pw.Show();
}
and my previewForm.cs construct to handle the preview:
public previewForm(IntPtr previewHandle)
{
InitializeComponent();
IntPtr myHandle = this.Handle;
SetParent(myHandle, previewHandle);
SetWindowLong(myHandle, -16, new IntPtr(GetWindowLong(myHandle, -16) | 0x40000000));
Rectangle ParentRect;
GetClientRect(previewHandle, out ParentRect);
this.Size = ParentRect.Size;
this.pictureBox1.Size = ParentRect.Size;
this.Location = new Point(0, 0);
}
So I used a mix of a WPF form and a regular windows form to accomplish this. And the performance is fine. Only uses like 14-18MB of RAM and practically no CPU.

C# - Need to Psuedo Click a Window

Well, first off, what I'm trying to do is click a specific point inside a flash object, inside of a webbrowser control. I'm not sure why it isn't working, but I cannot seem to click any window, be it notepad, or the actual program.
Here is my code that I'm using.
[DllImport("user32.dll", SetLastError = true)]
public static extern IntPtr FindWindowEx(IntPtr parentHandle, IntPtr childAfter, string className, IntPtr windowTitle);
[DllImport("user32.dll")]
public static extern IntPtr FindWindow(String sClassName, String sAppName);
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = false)]
static extern IntPtr SendMessage(IntPtr hWnd, int Msg, int wParam, int lParam);
[DllImport("user32.dll", SetLastError = true)]
static extern bool PostMessage(IntPtr hWnd, uint Msg, int wParam, int lParam);
public IntPtr find()
{
return this.Handle;//FindWindow("", "Form1");
}
public enum WMessages : int
{
WM_LBUTTONDOWN = 0x201, //Left mousebutton down
WM_LBUTTONUP = 0x202, //Left mousebutton up
WM_LBUTTONDBLCLK = 0x203, //Left mousebutton doubleclick
WM_RBUTTONDOWN = 0x204, //Right mousebutton down
WM_RBUTTONUP = 0x205, //Right mousebutton up
WM_RBUTTONDBLCLK = 0x206, //Right mousebutton do
}
private int MAKELPARAM(int p, int p_2)
{
return ((p_2 << 16) | (p & 0xFFFF));
}
/** This is the non-working code **/
public void DoMouseLeftClick(IntPtr handle, Point x)
{
SendMessage(handle, (int)WMessages.WM_LBUTTONDOWN, 0, MAKELPARAM(x.X, x.Y));
SendMessage(handle, (int)WMessages.WM_LBUTTONUP, 0, MAKELPARAM(x.X, x.Y));
return;
//I have tried PostMessage, and SendMessage, and both of them at the same time, and neither works.
PostMessage(handle, (uint)WMessages.WM_LBUTTONDOWN, 0, MAKELPARAM(x.X, x.Y));
PostMessage(handle, (uint)WMessages.WM_LBUTTONUP, 0, MAKELPARAM(x.X, x.Y));
}
private void timer2_Tick(object sender, EventArgs e)
{
//I try hovering my mouse over a button I added to the form, and nothing happens.
DoMouseLeftClick(find(), Cursor.Position);
}
So, I have tried using PostMessage, and SendMessage, and neither of those seem to work.
All I need it to do is to click on a specific point.
Also, I need to mention that I can't use mouse_event, because from what I know, the window needs to be active, plus the cursor needs to be over the point you are clicking. I am making a bot that automatically does a process in a flash object, so that's why I can't use mouse_event.
Thanks for your help guys.

I had the same problem.
I tried to draw something in the MS Paint. It turned out that I was clicking on the main window but it turned out that MS Paint (and most of the applications) consist of many child windows and you actually want to click on the child. So I had to change my code from:
IntPtr handle = FindWindow(null, "Untitled - Paint");
PostMessage(handle, (uint)MOUSE_BUTTONS.LEFT_DOWN, 0, lparam);
to
IntPtr handle = FindWindow(null, "Untitled - Paint");
handle = FindWindowEx(handle, IntPtr.Zero, "MSPaintView", null);
canvasHandle = FindWindowEx(handle, IntPtr.Zero, "Afx:00007FF676DD0000:8", null);
PostMessage(canvasHandle, (uint)MOUSE_BUTTONS.LEFT_DOWN, 0, lparam);
You need to use tools like Spy++ for Windows that comes with C++ Visual Studio package if you want to debug these kind of things (even if you program in C#)
Hope it helps someone.

For the WM_LBUTTONDOWN, you may need to specify which button. Take reference for: https://msdn.microsoft.com/en-us/library/windows/desktop/ms645607(v=vs.85).aspx
I used:
SendMessage(hWnd, (int)WMessages.WM_RBUTTONDOWN, (int)KeyDownMessage.MK_LBUTTON, MAKELPARAM(x, y));

How do I set the focus to the Desktop from within my C# application

Winforms App. .Net 3.5.
I need to set the focus from my C# application to the user's desktop (almost like simulating a mouse click on the desktop).
Can someone please show me how to do this with C#? I just want to set focus on the desktop so the focus is no longer on my application but I want to do this from within my application.
Edit: An answer below works by setting the focus to the desktop, but it minimizes all the open windows on the user's desktop.
Is there a way I can maybe set the focus to the next open window on the desktop instead? I just want to get the focus off of my application (without minimizing my application or hiding it). I just want to move focus to somewhere else. Maybe the desktop was not the best choice if it will minimize all the user's open windows/applications.

This should do it for you.
using System;
using System.Runtime.InteropServices;
namespace ConsoleApplication1 {
class Program {
[DllImport("user32.dll", EntryPoint = "FindWindow", SetLastError = true)]
static extern IntPtr FindWindow(string lpClassName, string lpWindowName);
[DllImport("user32.dll", EntryPoint = "SendMessage", SetLastError = true)]
static extern IntPtr SendMessage(IntPtr hWnd, Int32 Msg, IntPtr wParam, IntPtr lParam);
const int WM_COMMAND = 0x111;
const int MIN_ALL = 419;
const int MIN_ALL_UNDO = 416;
static void Main(string[] args) {
IntPtr lHwnd = FindWindow("Shell_TrayWnd", null);
SendMessage(lHwnd, WM_COMMAND, (IntPtr)MIN_ALL, IntPtr.Zero);
System.Threading.Thread.Sleep(2000);
SendMessage(lHwnd, WM_COMMAND, (IntPtr)MIN_ALL_UNDO, IntPtr.Zero);
}
}
}
Get Next Window
I don't have a code example ready for these two but I'm going to give you the links to both. The first think you need to do is call GetWindow. After doing that you'll want to call SwitchToThisWindow passing in the pointer you received from GetWindow.

You can add this COM object in your project:
Microsoft Shell Controls And Automation
And then just call:
Shell32.ShellClass shell = new Shell32.ShellClass();
shell.MinimizeAll();
This will minimize all the windows and then focus the desktop. Otherwise, if you have your window non-full screen then you can simulate the mouse click using:
//This is a replacement for Cursor.Position in WinForms
[System.Runtime.InteropServices.DllImport("user32.dll")]
static extern bool SetCursorPos(int x, int y);
[System.Runtime.InteropServices.DllImport("user32.dll")]
public static extern void mouse_event(int dwFlags, int dx, int dy, int cButtons, int dwExtraInfo);
public const int MOUSEEVENTF_LEFTDOWN = 0x02;
public const int MOUSEEVENTF_LEFTUP = 0x04;
//This simulates a left mouse click
public static void LeftMouseClick(int xpos, int ypos)
{
SetCursorPos(xpos, ypos);
mouse_event(MOUSEEVENTF_LEFTDOWN, xpos, ypos, 0, 0);
mouse_event(MOUSEEVENTF_LEFTUP, xpos, ypos, 0, 0);
}
You can calculate coordinates by looking at your window startup location plus height/width and select a available space (that will be the desktop indeed).

Move external application to the front of the screen

The application that I'm running needs to call a separate app to do some scanning. I'm calling the other application by starting a new System.Diagnostics.Process. Once I get that process, I call a method to give that application the focus. I've tried two different ways to give that external app the focus, but neither are working. Could someone help?
Here's the code:
using System.Runtime.InteropServices;
[DllImport("user32.dll")]
private static extern bool ShowWindow(IntPtr hWnd, uint windowStyle);
[DllImport("user32.dll")]
private static extern bool SetWindowPos(IntPtr hWnd,
IntPtr hWndInsertAfter, int x, int y, int cx, int cy, uint uFlags);
[DllImport("user32.dll")]
private static extern bool SetForegroundWindow(IntPtr hWnd);
private static void GiveSpecifiedAppTheFocus(int processID)
{
try
{
Process p = Process.GetProcessById(processID);
ShowWindow(p.MainWindowHandle, 1);
SetWindowPos(p.MainWindowHandle, new IntPtr(-1), 0, 0, 0, 0, 3);
//SetForegroundWindow(p.MainWindowHandle);
}
catch
{
throw;
}
}
First scenario uses the ShowWindow and SetWindowPos methods, the other method uses the SetForegroundWindow method. Neither will work...
Am I using the wrong methods, or do I have an error in the code that I'm using? Thanks all!

Use SetWindowPos, but whenever you don't want the window to be the topmost anymore call it again with the second parameter set to -2 (HWND_NOTOPMOST) instead of -1(HWND_TOPMOST)

Try setting your process to the background ie: this.SendToBack(); This is just another solution, partial fix.