We Keep Coding

C# - trigger key down event for active control

I found command System.Windows.Forms.SendKeys.Send() for sending keypress some key. This function work if open external app like a notepad and set focus and I will be see that my Key printed in this text field. How do same but with key down event, System.Windows.Forms.SendKeys.SendDown("A");, for example?
I tried call in Timer this command System.Windows.Forms.SendKeys.Send() but have runtime error associated with very fast taped.

You can't use the SendKeys class for that, unfortunately. You will need to go to a lower level API.
Poking a window with a keydown message
In Windows, keyboard events are sent to windows and controls via the Windows message pump. A piece of code using PostMessage should do the trick:
[DllImport("user32.dll")]
static extern bool PostMessage(IntPtr hWnd, uint Msg, int wParam, int lParam);
const uint WM_KEYDOWN = 0x0100;
void SendKeyDownToProcess(string processName, System.Windows.Forms.Keys key)
{
Process p = Process.GetProcessesByName(processName).FirstOrDefault();
if (p != null)
{
PostMessage(p.MainWindowHandle, WM_KEYDOWN, (int)key, 0);
}
}
Note that the application receiving these events may not do anything with it until a corresponding WM_KEYUP is received. You can get other message constants from here.
Poking a control other than the main window
The above code will send a keydown to the "MainWindowHandle." If you need to send it to something else (e.g. the active control) you will need to call PostMessage with a handle other than p.MainWindowHandle. The question is... how do you get that handle?
This is actually very involved... you will need to temporarily attach your thread to the window's message input and poke it to figure out what the handle is. This can only work if the current thread exists in a Windows Forms application and has an active message loop.
An explanation can be found here, as well as this example:
using System.Runtime.InteropServices;
public partial class FormMain : Form
{
[DllImport("user32.dll")]
static extern IntPtr GetForegroundWindow();
[DllImport("user32.dll")]
static extern IntPtr GetWindowThreadProcessId(IntPtr hWnd, IntPtr ProcessId);
[DllImport("user32.dll")]
static extern IntPtr AttachThreadInput(IntPtr idAttach,
IntPtr idAttachTo, bool fAttach);
[DllImport("user32.dll")]
static extern IntPtr GetFocus();
public FormMain()
{
InitializeComponent();
}
private void timerUpdate_Tick(object sender, EventArgs e)
{
labelHandle.Text = "hWnd: " +
FocusedControlInActiveWindow().ToString();
}
private IntPtr FocusedControlInActiveWindow()
{
IntPtr activeWindowHandle = GetForegroundWindow();
IntPtr activeWindowThread =
GetWindowThreadProcessId(activeWindowHandle, IntPtr.Zero);
IntPtr thisWindowThread = GetWindowThreadProcessId(this.Handle, IntPtr.Zero);
AttachThreadInput(activeWindowThread, thisWindowThread, true);
IntPtr focusedControlHandle = GetFocus();
AttachThreadInput(activeWindowThread, thisWindowThread, false);
return focusedControlHandle;
}
}
The good news-- if SendKeys worked for you, then you might not need to do all this-- SendKeys also sends messages to the main window handle.

WebBrowser control not responding to InvokeMember("click")

After spending 5 days of my life, I'm about to give up on this, but am consulting the experts once before that.
I have a WebBrowser control that loads a webpage and I programmatically scrape its contents. Clicking a particular menu item in the page brings up File Open dialog when done in IE (or any other browser). But clicking the same button in WebBrowser control using InvokeMember() apparently doesn't do anything no matter what. I've gone through several SO questions such as Setting Browser Features to make sure my control behaves exactly like IE, but that hasn't succeeded.
I went as far as inspecting the actual javascript function that the button is executing behind the scene and calling it manually using HtmlDocument.InvokeScript() but couldn't do that because the underlying function takes an argument of MouseEvent type (the click event actually) and I'm not sure how can I create that object in C#.
Another approach was to set focus to that particular button and then try SendKeys, but that won't work because the WebBrowser control is not visible. It is just an in-memory instance. To be more specific, the WebBrowser
EDIT
On a reader's request, here's the simple code that I'm using to find the element:
var MyButton = WB.Document.GetElementById("processfilelink");
processfilelink is an anchor tag (<a href='#' ... >) and I have confirmed that this element actually exists in the body of the document. The webpage uses jQuery's delegate feature to bind this anchor's click event to the target function. After locating the button, I simply call InvokeMember() like this:
MyButton.InvokeMember("click");
Note: I also see bindings for mousedown, mouseup and focus events in the page code. I expect all these events to automatically fire when one invokes click, but just to be sure I added InvokeMember calls for these events too. Results are no better.

From the comments:
... load this page in full IE browser, use F12 Tools to debug it and
execute button.click() in JavaScript console. Does it work as expected
this way?
So, you've tried that, and the result is:
... now that's interesting. It doesn't work! But clicking on the item
by hand does work flawlessly. What's going on here?
I suspected that as MyButton.InvokeMember("click") doesn't work. Apparently, the page handles this click by other means than via onclick event. Most likely, it uses onmousedown or onmouseup events. Study the page's scripting logic to verify if that's the case, use F12 debugger and put some break points.
Updated, if it turns out the page indeed uses onmousedown/onmouseup, you'd need to make your WebBrowser visible and automate it by posting WM_LBUTTONDOWN:
using System;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Windows.Forms;
namespace WindowsFormsApplication_22979038
{
public partial class MainForm : Form
{
public MainForm()
{
InitializeComponent();
}
private void MainForm_Load(object sender, EventArgs e)
{
this.webBrowser.DocumentText = "<a id='goLink' href='javascript:alert(\"Hello!\"),undefined'>Go</a><script></script>";
this.webBrowser.DocumentCompleted += webBrowser_DocumentCompleted;
}
void webBrowser_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
{
var element = this.webBrowser.Document.GetElementById("goLink");
element.Focus();
var hwnd = GetFocus();
if (!IsChild(this.webBrowser.Handle, hwnd))
throw new ApplicationException("Unexpected focused window.");
var rect = GetElementRect(element);
IntPtr wParam = (IntPtr)MK_LBUTTON;
IntPtr lParam = (IntPtr)(rect.Left | rect.Top << 16);
PostMessage(hwnd, WM_LBUTTONDOWN, wParam, lParam);
PostMessage(hwnd, WM_LBUTTONUP, wParam, lParam);
}
// get the element rect in window client area coordinates
static Rectangle GetElementRect(HtmlElement element)
{
var rect = element.OffsetRectangle;
int left = 0, top = 0;
var parent = element;
while (true)
{
parent = parent.OffsetParent;
if (parent == null)
return new Rectangle(rect.X + left, rect.Y + top, rect.Width, rect.Height);
var parentRect = parent.OffsetRectangle;
left += parentRect.Left;
top += parentRect.Top;
}
}
// interop
const int MK_LBUTTON = 0x0001;
const int WM_LBUTTONDOWN = 0x0201;
const int WM_LBUTTONUP = 0x0202;
[StructLayout(LayoutKind.Sequential)]
public struct POINT
{
public int x;
public int y;
}
[DllImport("User32.dll", CharSet = CharSet.Auto)]
static extern int PostMessage(IntPtr hwnd, int msg, IntPtr wparam, IntPtr lparam);
[DllImport("User32.dll", ExactSpelling = true, CharSet = CharSet.Auto)]
static extern IntPtr GetFocus();
[DllImport("User32.dll", SetLastError = true, ExactSpelling = true, CharSet = CharSet.Auto)]
static extern bool IsChild(IntPtr hWndParent, IntPtr hWnd);
}
}

Simulating mouse click in webbrowser control

I'm building a screen scraping utility to automate the population of legacy web forms. After researching Selenium and other automation frameworks, I settled on simply using the C# WebBrower control and so far it's easy to use and working well. One of the webforms, however, utilizes a java-driven navigation pane that I can't control as I would with html elements. Therefore, my plan is to find the screen coordinates of the various navigation elements and simulate mouse clicks.
I found a few relevant posts and was led to try something like this (code below). It doesn't work, though, and I can't figure out why. I've tried passing handles to both the WebBrowser control and its parent form in the ClickOn() call but neither works. I looked at it using Spy++ and it appears that no messages are being triggered. Anyone know what the culprit might be?
Also, I should add that there's no java involved yet. I'm just trying to click on an html button at this point to validate the ClickOn method.
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
browser.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(onDocLoaded);
}
private void onLoad(object sender, EventArgs e)
{
browser.Navigate(#"http://www.dummysite.com/");
}
void onDocLoaded(object sender, WebBrowserDocumentCompletedEventArgs e )
{
ClickOn(browser.Handle, 899, 463);
}
[DllImport("user32.dll", EntryPoint = "PostMessage", CharSet = CharSet.Auto)]
static extern bool PostMessage1(IntPtr hWnd, uint Msg,
int wParam, int lParam);
private void ClickOn(IntPtr hControl, int x, int y)
{
uint WM_LBUTTONDOWN = 0x0201;
uint WM_LBUTTONUP = 0x0202;
PostMessage1(hControl, WM_LBUTTONDOWN, x, y);
PostMessage1(hControl, WM_LBUTTONUP, x, y);
}
}

try calling ClickOn from javascript after window.load event

Send emulated events to another window

I send mouse events to another application in the following way. The problem is, this works for some applications but not for others.
Why?
using System.Runtime.InteropServices;
using System.Diagnostics;
namespace WpfApplication1
{
public partial class MainWindow : Window
{
[DllImport("user32.dll")]
private static extern int SendMessage(IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam);
private const int downclick = 0x201;
private const int upclick = 0x202;
IntPtr handle = IntPtr.Zero;
public MainWindow()
{
InitializeComponent();
}
private void button1_Click(object sender, RoutedEventArgs e)
{
foreach (Process p in Process.GetProcessesByName("mspaint"))
{
IntPtr handle = p.MainWindowHandle;
int X = 50;
int Y = 380;
IntPtr lParam = (IntPtr)((Y << 16) | X);
IntPtr wParam = IntPtr.Zero;
SendMessage(handle, downclick, wParam, lParam);
SendMessage(handle, upclick, wParam, lParam);
}
}
}
}
Using Spy++ I see that the application recieves the following data:
<00062> 0004052C S WM_LBUTTONDOWN fwKeys:0000 xPos:50 yPos:380
<00063> 0004052C R WM_LBUTTONDOWN
<00064> 0004052C S WM_LBUTTONUP fwKeys:0000 xPos:50 yPos:380
<00065> 0004052C R WM_LBUTTONUP
I assume that the events themselves are correct. But I don't know why it works for some software but not for others. How can I send mouse messages from one window to another?
The software where I want to send the messages is not always visible.
Is it possible at all?

No it's not possible in any reliable way - as you've found out in your testing. The mouse messages are only one part of the input. Windows keeps an input state and just sending messages will not update that input state. And you're also ignoring mouse move messages, etc.
For example in your WinForms application you can use the MousePosition property to get the current mouse positon. Sending messages can't simulate that.
Also you can't send the mouse message to the main window handle, you would have to find the exact button you want to click on and send the message directly to the correct button.
So maybe it will work if the application is only listening for mouse messages this will work, but if not they it won't.
They supported way to simulate mouse clicks, is the SendInput function. But that won't work with minimized applications. It literally goes through the entire Windows input process and will move the mouse cursor - which means that the application has to be visible on the screen.
Here's some information, it talks about keyboard events, but similar logic applies:
http://blogs.msdn.com/b/oldnewthing/archive/2005/05/30/423202.aspx
http://blogs.msdn.com/b/oldnewthing/archive/2010/12/21/10107494.aspx

Call method in already running .NET assembly from different app

I don't know if you can do this, but basicly I need to be able to call a method in already running .NET process from a different assembly that don't share the same process.
Basically what I have is a application and when it calls a .net method it loads the assembly that contains that method into into a appdomian and then calls the method.
I need to get from the loaded assembly into another process and call a supplied method.
I know this might not help but this is picture of what happens:
alt text http://img527.imageshack.us/img527/6960/probt.jpg
Sorry for the low quality.

Do you have control over the apps? If so, just have them 'open a channel' to each other. Perhaps you can just use a socket, to write to one from the other, or a named pipe, or something similar. It'd what I'd do, if I was writing both of them.

The easiest way is to use ServiceHost to expose a WCF service. You can not directed access an object from a process from another process. The only option is to send a message to the other process interpret the message and execute a action.
Here you can find a quick example:
http://blogs.microsoft.co.il/blogs/davids/archive/2009/05/31/a-hands-on-lab-for-wcf-moc-6461.aspx
Hope this helps.

This question has been marked as a duplicate of this. And people that decided that say in this question there is the answer for that question. Well, this question does not have any accepted answer yet. An may be my answer may help. This solution works with WPF but its essence is indepent of WPF indeed
I have researched a little about the topic since it seems interesting. I think you could do this by using Win32. I have made a very very simple sample. Two WPF applications, first named WpfSender and second named WpfListener. WpfSender will send a message to WpfListener process.
WpfSender only has one button that send the message once it is clicked. WpfListener is only an empty window that will show a message box when receiving the message from WpfSender.
Here is the code behind for WpfSender
using System;
using System.Diagnostics;
using System.Linq;
using System.Runtime.InteropServices;
using System.Windows;
namespace WpfSender
{
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
private void ButtonBase_OnClick(object sender, RoutedEventArgs e)
{
var process = Process.GetProcessesByName("WpfListener").FirstOrDefault();
if (process == null)
{
MessageBox.Show("Listener not running");
}
else
{
SendMessage(process.MainWindowHandle, RF_TESTMESSAGE, IntPtr.Zero, IntPtr.Zero);
}
}
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern IntPtr SendMessage(IntPtr hwnd, uint Msg, IntPtr wParam, IntPtr lParam);
private const int RF_TESTMESSAGE = 0xA123;
}
}
You use Win32 api for sending messages across windows applications
Here is the code for WpfListener
using System;
using System.Windows;
using System.Windows.Interop;
namespace WpfListener
{
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
private void MainWindow_OnLoaded(object sender, RoutedEventArgs e)
{
HwndSource source = HwndSource.FromHwnd(new WindowInteropHelper(this).Handle);
source.AddHook(WndProc);
}
private static IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
{
if (msg == RF_TESTMESSAGE)
{
MessageBox.Show("I receive a msg here a I can call the method");
handled = true;
}
return IntPtr.Zero;
}
private const int RF_TESTMESSAGE = 0xA123;
}
}
I don not write here the XAML since it is very simple. Again this is a very simple sample that shows you how to achieve cross application message sending. The limit is your imagination. You can declare many int constants each one representing an action, an then in a switch statement you can call selected action.
I have to say that I follow two articles that I found in my research:
For knowing how to handle WndProc in Wpf
For knowing how to send messages using win32 api
Hope this helps!