Reading c++ window in C# using handler - c#

I am implementing a plugin for a product called AmiBroker in C#.
AmiBroker is a trading software it has exposed a few functions which can be used by 3rd party vendors to pass the stock data to solution. So, we can create a plugin in C# which can be recognized by AmiBroker.
In my scenario I am getting a handler of Main Window of AmiBroker [Note : AmiBroker is fully written in C++] In C# we can retrieve the handler of Main Window, so using this handle can I read the data of the window e.g. Child windows, Panels showing stock lists or things which are visible to the User, and if so, how would I go about doing this?

You can, but it's messy. I literally just worked on something very similar. Pinvoke.net is great for this stuff, but I'll show you some examples of how I'd find controls. If AmiBroker has any documentation for control names or AccessibleNames or anything that allows you to find the exact controls you're looking for, that'd be killer. Because if they're ambiguously named, you're gonna have a helluva time finding the ones you're specifically looking for. But basically, what you'll want to do is EnumChildWindows on the handle you have, iterate through them and look for a unique property to allow you to find the control you want. Then you'll need to execute a specific SendMessage to get the text off of a control (GetWindowText or whatever it's called only works for labels). Code as follows, adapted or swiped from Pinvoke.net at some point (great starting point):
[DllImport("user32")]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool EnumChildWindows(IntPtr window, EnumWindowProc callback, IntPtr i);
public static extern uint GetClassName(IntPtr handle, StringBuilder name, int maxLength);
public delegate bool EnumWindowProc(IntPtr hWnd, IntPtr parameter);
private static List<IntPtr> GetChildWindows(IntPtr parent)
{
List<IntPtr> result = new List<IntPtr>();
GCHandle listHandle = GCHandle.Alloc(result);
try
{
EnumWindowProc childProc = new EnumWindowProc(EnumWindow);
EnumChildWindows(parent, childProc, GCHandle.ToIntPtr(listHandle));
}
finally
{
if (listHandle.IsAllocated)
listHandle.Free();
}
return result;
}
private static bool EnumWindow(IntPtr handle, IntPtr pointer)
{
GCHandle gch = GCHandle.FromIntPtr(pointer);
List<IntPtr> list = gch.Target as List<IntPtr>;
if (list == null)
{
throw new InvalidCastException("GCHandle Target could not be cast as List<IntPtr>");
}
list.Add(handle);
// You can modify this to check to see if you want to cancel the operation, then return a null here
return true;
}
//THIS IS THE ONE YOU'LL CALL!
public static IntPtr GetWindowByClass(IntPtr mainWindow, string name)
{
List<IntPtr> windows = GetChildWindows(mainWindow);
foreach (IntPtr window in windows)
{
StringBuilder response = new StringBuilder();
response.Capacity = 500;
if (GetClassName(window, response, response.Capacity) > 0)
if (response.ToString() == name)
return window;
}
return IntPtr.Zero;
}
So basically it iterates through a whole set of child windows for the handle you have on the app, sees if the class name matches a control you're looking for, then returns it. There are thousands of ways to improve it (search for all the ones you want in a single shot, FindWindow MAY work by class name, etc.) but I wanted to show you more how it's done, not declare this is how it should be done. Finally, the call to get the text from the window/control is as follows (also adapted from pinvoke.net: look under User32.dll for all this stuff):
public static string GetText(IntPtr control)
{
StringBuilder builder = new StringBuilder(40);
IntPtr result = IntPtr.Zero;
uint response = SendMessageTimeoutText(control, 0xd, 40, builder, APITypes.SendMessageTimeoutFlags.SMTO_NORMAL, 2000, out result);
return builder.ToString();
}
[DllImport("user32.dll", EntryPoint = "SendMessageTimeout", SetLastError = true, CharSet = CharSet.Auto)]
public static extern uint SendMessageTimeoutText(
IntPtr hWnd,
int Msg, // Use WM_GETTEXT
int countOfChars,
StringBuilder text,
APITypes.SendMessageTimeoutFlags flags,
uint uTImeoutj,
out IntPtr result);
[Flags]
public enum SendMessageTimeoutFlags : uint
{
SMTO_NORMAL = 0x0,
SMTO_BLOCK = 0x1,
SMTO_ABORTIFHUNG = 0x2,
SMTO_NOTIMEOUTIFNOTHUNG = 0x8
}
EDIT: An addendum: the application I worked on to access another form like this actually didn't have unique control names, so I ended up using Spy++ to determine its place in the window hierarchy and pulling the children and selecting each child in turn. God help if you have to go that route, especially because it may not be consistent at all, especially if what you need is on a form that isn't created, or it's hidden behind another one that jumped it in the Z-Order (breaking your hierarchical list you're searching from). That said, you should know that EnumChildWindows will always enum ALL CHILD WINDOWS for a given window, no matter where they are in the hierarchy. If you really have to drill down and search for each control by its parent and its parent's parent, you'll need to use FindWindowEx, and declare the last child you looked at (or IntPtr.Zero if you want the first child):
[DllImport("user32.dll", SetLastError = true)]
public static extern IntPtr FindWindowEx(IntPtr parentHandle, IntPtr childAfter, string className, string windowTitle);

What you are asking for seems counter intuitive if the software you are writing the plug-in for provides an API. You should really be using that.
While it is possible to use the Win32 API to enumerate child windows of the main window given the handle and then use more Win32 API functions to determine the state of the UI (i.e. "read the data") it's going to be very tedious and error-prone.
Here's a link to MSDN for EnumChildWindows which will allow you to enumerate child windows for the main window given the handle.
If you want to go down that rabbit hole you might also find SendMessage and GetWindowText useful. And most definitely you should check out pinvoke.net if you are going to be using these Win32 APIs from C#.

Related

Listen for a save file dialog window in an application, then automate saving it?

Sorry if this is a vague question, it's a very specific case and difficult to explain. Here's what I'm trying to do (this is for a 64 bit Windows application by the way)
Look to see if a particular save file dialog window is open inside an application (image of it below, it's a dialog box that pops up inside of the application when exporting something)
Once I have a pointer to that window, somehow access and use its elements in such a way that I'm able to name the file I'm saving, navigate to a desired file path, then save it, all through code
Here's a photo of the window that I'm trying to control through code (for reference)
Image
So far I've been able to find code that gives me all the active windows, including the one I'm targeting. Here is that code:
using System;
using System.Diagnostics;
using System.ComponentModel;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using HWND = System.IntPtr;
using System.Text;
/// <summary>Contains functionality to get all the open windows.</summary>
public static class OpenWindowGetter
{
/// <summary>Returns a dictionary that contains the handle and title of all the open windows.</summary>
/// <returns>A dictionary that contains the handle and title of all the open windows.</returns>
public static IDictionary<HWND, string> GetOpenWindows()
{
HWND shellWindow = GetShellWindow();
Dictionary<HWND, string> windows = new Dictionary<HWND, string>();
EnumWindows(delegate (HWND hWnd, int lParam)
{
if (hWnd == shellWindow) return true;
if (!IsWindowVisible(hWnd)) return true;
int length = GetWindowTextLength(hWnd);
if (length == 0) return true;
StringBuilder builder = new StringBuilder(length);
GetWindowText(hWnd, builder, length + 1);
windows[hWnd] = builder.ToString();
return true;
}, 0);
return windows;
}
private delegate bool EnumWindowsProc(HWND hWnd, int lParam);
[DllImport("USER32.DLL")]
private static extern bool EnumWindows(EnumWindowsProc enumFunc, int lParam);
[DllImport("USER32.DLL")]
private static extern int GetWindowText(HWND hWnd, StringBuilder lpString, int nMaxCount);
[DllImport("USER32.DLL")]
private static extern int GetWindowTextLength(HWND hWnd);
[DllImport("USER32.DLL")]
private static extern bool IsWindowVisible(HWND hWnd);
[DllImport("USER32.DLL")]
private static extern IntPtr GetShellWindow();
}
namespace ConsoleApp1
{
class Program
{
static void Main(string[] args)
{
foreach (KeyValuePair<IntPtr, string> window in OpenWindowGetter.GetOpenWindows())
{
IntPtr handle = window.Key;
string title = window.Value;
Console.WriteLine("{0}: {1}", handle, title);
}
}
}
}
I'm not sure what to do from here. What I need now help with now is checking for the particular window I'm targeting (named Export Selection as seen in the photo).. then somehow get references to its components and control them.
I've looked into using Spy++ to get info about the components, and then using FindWindowEx and SendMessage to control them. This is not something I completely understand, as I'm limited in my C# knowledge. Is this the correct approach, and if so how would I go about doing it?
Yea, using Spy++ is a good approach to understand that application and its controls. As you seem already to be able to detect the correct window, the next step is now to use the SendMessage function to send data to the individual controls of the window. Look up in the Win32 API documentation to find the correct messages to send. I.e. you would use the WM_SETTEXT message to put text into the "File name" input box. See here: https://learn.microsoft.com/en-US/windows/win32/winmsg/wm-settext.
Or you use the SetWindowText function, which basically does the same, but is easier to use. You already have the prototype for the GetWindowText method declared in your code. The C# declaration for SetWindowText should be
[DllImport("USER32.DLL")]
private static extern int SetWindowText(HWND hWnd, String lpString);

Send keystroke to application in c# (sendkeys, postmessage, sendmessage all not working)

I am trying to do one of the following
1. open desired program and press a key programmatically
2. find open window of program and press a key programmatically
(either is fine)
I have tried numerous implementations of SendKeys.SendWait(), PostMessage(), and SendMessage() unsuccessfully. Below are my code snippets
//included all these for attempts
[DllImport("User32.dll")]
static extern IntPtr FindWindow(string lpClassName, string lpWindowName);
[DllImport("User32.dll")]
static extern int SetForegroundWindow(IntPtr hWnd);
[DllImport("User32.Dll", EntryPoint = "PostMessageA")]
static extern bool PostMessage(IntPtr hWnd, uint msg, int wParam, int lParam);
[DllImport("user32.dll")]
static extern byte VkKeyScan(char ch);
[DllImport("user32.dll", CharSet = CharSet.Auto)]
static extern IntPtr SendMessage(IntPtr hWnd, UInt32 Msg, IntPtr wParam, IntPtr lParam);
Get handle of window, variables used by sendmessage/postmessage/sendkeys
IntPtr ptrOBS = proc.Handle;//this works properly, proc is instantiated properly
//IntPtr ptrOBS = FindWindow(null, "Open Broadcaster Software v0.472b");
SetForegroundWindow(ptrOBS);
const UInt32 WM_CHAR = 0x0102;
const uint WM_KEYDOWN = 0x100;
const int VK_R = 0x52; // taken from http://msdn.microsoft.com/en-us/library/dd375731(v=vs.85).aspx
const int VK_S = 0x53;
SendMessage attempt:
SendMessage(ptrOBS, WM_KEYDOWN, (IntPtr)VK_R, (IntPtr)1);//tried both WM_CHAR and WM_KEYDOWN
PostMessage attempt:
string message = "rs";
bool sent = PostMessage(ptrOBS, WM_KEYDOWN, VkKeyScan(message[0]), 0);
SendKeys attempt:
SendKeys.SendWait("{r}");
Tried SetFocus on the parent window (application) and child window (button triggered by keypress im trying to send):
static void SetFocus(IntPtr hwndTarget, string childClassName)
{
// hwndTarget is the other app's main window
// ...
IntPtr targetThreadID = GetWindowThreadProcessId(hwndTarget, IntPtr.Zero); //target thread id
IntPtr myThreadID = GetCurrentThread(); // calling thread id, our thread id
try
{
bool lRet = AttachThreadInput(myThreadID, targetThreadID, -1); // attach current thread id to target window
// if it's not already in the foreground...
lRet = BringWindowToTop(hwndTarget);
SetForegroundWindow(hwndTarget);
// if you know the child win class name do something like this (enumerate windows using Win API again)...
IntPtr hwndChild = (IntPtr)1183492;//(IntPtr)EnumAllWindows(hwndTarget, childClassName).FirstOrDefault();
if (hwndChild == IntPtr.Zero)
{
// or use keyboard etc. to focus, i.e. send keys/input...
// SendInput (...);
return;
}
// you can use also the edit control's hwnd or some child window (of target) here
SetFocus(hwndChild); // hwndTarget);
SendKeys.SendWait("{r}");
}
finally
{
SendKeys.SendWait("{r}");
bool lRet = AttachThreadInput(myThreadID, targetThreadID, 0); //detach from foreground window
SendKeys.SendWait("{r}");
}
}
For NSGaga:
string windowName = "Open Broadcaster Software v0.472b";
IntPtr outerPtr = FindWindow(null, windowName);
IntPtr ptrOBS = (IntPtr)527814;//button that im trying to trigger keypress on
SetForegroundWindow(outerPtr);
SetForegroundWindow(ptrOBS);
SetFocus(outerPtr, "OBSWindowClass");//SetFocus(ptrOBS, "Button");
const UInt32 WM_CHAR = 0x0102;
const int VK_R = 0x52; // taken from http://msdn.microsoft.com/en-us/library/dd375731(v=vs.85).aspx
const int VK_S = 0x53;
//SetForegroundWindow(ptrOBS);
System.Threading.Thread.Sleep(3000);
SendKeys.SendWait("{r}");
SendMessage(outerPtr, WM_KEYDOWN, (IntPtr)VK_R, (IntPtr)1);
PostMessage(outerPtr, WM_KEYDOWN, VkKeyScan('r'), 0);
You cannot reliably use SendMessage and PostMessage for synthesizing keyboard input. They are just not designed for this. These messages (WM_CHAR, WM_KEYDOWN, etc.) are notifications raised by lower-level subsystems when keyboard input has been received, processed, and forwarded on to the appropriate recipient. Sending or posting these messages yourself is like prank-calling someone.
SendKeys (like all other input synthesizer methods, including the SendInput function which was explicitly designed for synthesizing keyboard input and in at least some implementation is what SendKeys actually uses under the hood) works only when the window you wish to receive the keyboard input has the focus. In Windows, only focused (active) windows receive input events.
So SendKeys is probably the way to go if you're ever going to get this to work (either that or P/Invoking SendInput and all of its associated structures), but you do need to respect the caveat that the recipient window must have the focus. Otherwise, it's not going to get anything.
It looks like from your sample code that you're trying to use the SetForegroundWindow function to meet this precondition. Unfortunately, you're passing it an invalid value, and not doing any error checking that might alert you to this mistake. Specifically, this code is wrong:
IntPtr ptrOBS = proc.Handle;//this works properly, proc is instantiated properly
SetForegroundWindow(ptrOBS); // WRONG, ptrOBS is not a window handle
Even if I trust you on ptrOBS being initialized correctly, that makes it a valid handle to a process, which is a very different thing than a valid handle to a window. Aside from the obvious nominal differences, processes can have multiple windows and only a single window can have the focus (i.e., be "in the foreground").
You will need to obtain the handle to a particular window before calling SetForegroundWindow, and given that we know a process can have multiple windows, that can be tricky. You need some reliable way of determining which window you want. Lots of people accomplish this by hard-coding the name of the window as a string, which works great until the target app is recompiled and this implementation detail changes. The only bulletproof way that I can think of is to have the user click the target window and your code to retrieve the handle of the window that is currently under the mouse pointer.
And of course all of this assumes that you've observed the restrictions on the use of SetForegroundWindow, enumerated in the "Remarks" section of the linked SDK documentation.
There is lot of trial and error with that, to get it working
Here is a bit of code I posted before, you might wanna give a try (and there is some more info attached)...
Pinvoke SetFocus to a particular control
Try setting focus first (using the mechanism mentioned) - and then using SendKeys or SendInput.
Here is some detailed code for SendInput...
How to send a string to other application including Microsoft Word

C# Copy-paste multiple times not working

In Visual C#, I'm trying to take text from multiple textboxes (one at a time) and paste them into Notepad. I do this by copying to the clipboard, alt-tabbing, and then pasting into notepad...then again for the other textboxes. This code represents this idea:
subBox1.SelectAll();
subBox1.Copy();
SendKeys.Send("%{TAB}"); // alt+tab
SendKeys.Send("^v"); // paste
SendKeys.Send("{TAB}"); // tab
subBox2.SelectAll();
subBox2.Copy();
SendKeys.Send("^v");
SendKeys.Send("{TAB}");
subBox3.SelectAll();
subBox3.Copy();
SendKeys.Send("^v");
SendKeys.Send("{TAB}");
As you can see, this copies and pastes from three textboxes (named subBox1, 2, and 3). But, for some reason, only the last textbox's contents are getting copied over. This also happens if I comment out the third box...in that case, only the second textbox's content gets copied over. I've tried using the SelectAll() and Copy() as you see here, as well as the Clipboard class. Both have the same issue.
For example, if the textbox contents are "asdf", "qwer", and "zxcv" respectively, all I see is "zxcv" three times.
Any idea why this is happening? I've been stuck on this for about an hour now and have no idea what's going on.
Thanks a ton!
SendKeys doesn't wait for the other application to process the keys you send, so by the time notepad gets around to processing your keypresses, your program has already copied subBox3's text over the top of the other texts.
You need to use SendWait instead.
As well, instead of sending Alt+Tab, you could use something like this:
[DllImport("user32.dll", SetLastError = true)]
static extern IntPtr FindWindow(string lpClassName, string lpWindowName);
[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool SetForegroundWindow(IntPtr hWnd);
// ...
SetForegroundWindow(FindWindow(null, "Untitled - Notepad"));
I'd use SendMessage for more accurate results. To use SendMessage, you first need a valid window handle to the text area of Notepad. This can be done in a variety of ways, but I prefer just using my simple child lookup function.
You will need the following namespace imports and PInvoke declarations:
using System;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Collections.Generic;
using System.Text;
//pinvoke
[DllImport("user32.dll", CharSet = CharSet.Auto)]
private static extern IntPtr SendMessage(IntPtr hWnd, UInt32 Msg, IntPtr wParam, IntPtr lParam);
[DllImport("user32.dll")]
[return:MarshalAs(UnmanagedType.Bool)]
private static extern bool GetClassName(IntPtr hWnd, StringBuilder lpClassName, int nMaxCount);
[DllImport("user32.dll")]
private static extern int GetWindowTextLength(IntPtr hWnd);
[DllImport("user32.dll")]
[return:MarshalAs(UnmanagedType.Bool)]
private static extern bool EnumChildWindows(IntPtr hParent, delChildWndProc callback, IntPtr lpParam);
//delegate callback for EnumChildWindows:
[return:MarshalAs(UnmanagedType.Bool)]
private delegate bool delChildWndProc(IntPtr hWnd, IntPtr lParam);
Now, onto the child window lookup. Basically works similar to FindWindowEx, but I wanted to write my own, and it retrieves multiple windows which can be nice. It uses the following wrapper class to describe information between calls:
private class WindowLookup
{
public string LookupName { get; private set; }
public List<IntPtr> MatchedChildren { get; private set; }
public int Depth { get; set; }
public int MaxDepth { get; set; }
public WindowLookup(string lookup, int maxdepth)
{
this.MatchedChildren = new List<IntPtr>();
this.LookupName = lookup;
this.MaxDepth = maxdepth;
if (this.MaxDepth > 0)
this.MaxDepth++; //account for the depth past the parent control.
this.Depth = 0;
}
}
And then the following functions do all the work:
private static List<IntPtr> FindAllWindows(IntPtr hParent, string className, int maxdepth = 0)
{
var lookup = new WindowLookup(className, maxdepth);
var gcAlloc = GCHandle.Alloc(lookup);
try
{
LookupChildProc(hParent, GCHandle.ToIntPtr(gcAlloc));
}
finally
{
if (gcAlloc.IsAllocated)
gcAlloc.Free();
}
return lookup.MatchedChildren;
}
private static bool LookupChildProc(IntPtr hChild, IntPtr lParam)
{
var handle = GCHandle.FromIntPtr(lParam);
WindowLookup lookup = null;
if (handle.IsAllocated && (lookup = handle.Target as WindowLookup) != null)
{
if (lookup.Depth < lookup.MaxDepth || lookup.MaxDepth == 0)
{
lookup.Depth++;
var builder = new StringBuilder(256);
if (GetClassName(hChild, builder, builder.Capacity) && builder.ToString().ToLower() == lookup.LookupName.ToLower())
lookup.MatchedChildren.Add(hChild);
EnumChildWindows(hChild, LookupChildProc, lParam);
}
}
return true;
}
You don't need to worry about the implementation of these functions too much, they'll work as-is. The key thing is that using these functions, you can find the handle to notepad's Edit window (the text area you type in) very easily.
var notepads = Process.GetProcessesByName("notepad");
if (notepads.Length > 0)
{
foreach(var notepad in notepads) //iterate through all the running notepad processes. Of course, you can filter this by processId or whatever.
{
foreach(var edit in FindAllWindows(notepad.MainWindowHandle, "Edit"))
{
//next part of the code will go here, read on.
}
}
}
Now, where I left the code was in the middle of a loop through the "Edit" windows of each notepad process running at the time. Now that we have a valid window handle, we can use SendMessage to send stuff to it. In particular, appending text. I wrote the following function to handle appending text to a remote control:
private static void AppendWindowText(IntPtr hWnd, string text)
{
if (hWnd != IntPtr.Zero)
{
//for your reference, 0x0E (WM_GETTEXTLENGTH), 0xB1 (EM_SETSEL), 0xC2 (EM_REPLACESEL)
int len = SendMessage(hWnd, 0x000E, IntPtr.Zero, IntPtr.Zero).ToInt32();
var unmanaged = Marshal.StringToHGlobalAuto(text);
SendMessage(hWnd, 0x00B1, new IntPtr(len), new IntPtr(len));
SendMessage(hWnd, 0x00C2, IntPtr.Zero, unmanaged);
Marshal.FreeHGlobal(unmanaged);
}
}
Now that we have our AppendWindowText function, you can add a function call to it in the nested loop above (where I put the comment):
AppendWindowText(edit, "Some text here");
And there you have it. It's a bit of a wordy response, but in the end this method is far more reliable than using SendKeys and focusing the window etc. You never need to lose focus of your own application.
If you have any questions, feel free to comment and I'll answer as best I can.
Cheers,
J
EDIT: Some references:
SendMessage function (MSDN)
EnumChildWindows function (MSDN)
Appending text using SendMessage

How to capture data in a window

I have a desktop application installed on my machine. When I start a program some kind of window gets open. let's say, something like this (just example):
So, I want to write an application in C# that will find this window and capture some data from it.
What tools should I look at? I want to go with a path of least resistance.
I need to capture images, text from textboxes, and also find controls by text and click on them.
I suggest you use the cool but little-known UI Automation API for this work.
For this, the first thing to test is launch the associated UISpy tool. It will display a tree of all accessible windows on screen. It also is able to run some actions like pressing a menu, selecting an item, etc. This is using what's called UI Automation Control Patterns, which provide a way to categorize and expose a control's functionality independent of the control type or the appearance of the control.
So, if you can automate this application with UI Spy, you also can do the exact same thing using .NET code (UISpy is itself simply using the underlying API).
Here is an interesting tutorial article about UI automation programming: The Microsoft UI Automation Library
You should start enumerating handles of all windows for that process :
https://stackoverflow.com/a/2584672/351383
Then for each handle get information about text and position, with position infomation you can take screenshots of desktop on that position to get images AFAIK there is no other way to get images from a window of running application.
When you got screen positions of the controls then use from link below to simulate left mouse click, search windows for some text and then click on some point inside control, here is the method that will click a point :
https://stackoverflow.com/a/10355905/351383
I put toghether quick class to gather that data for process :
public static class ProcessSpy
{
public static List<ProcessSpyData> GetDataForProcess(string processName)
{
var result = new List<ProcessSpyData>();
Process myProc = Process.GetProcessesByName(processName).FirstOrDefault();
if (myProc != null)
{
var myHandles = EnumerateProcessWindowHandles(myProc);
foreach (IntPtr wndHandle in myHandles)
{
result.Add(new ProcessSpyData(wndHandle));
}
}
return result;
}
delegate bool EnumThreadDelegate(IntPtr hWnd, IntPtr lParam);
[DllImport("user32.dll")]
static extern bool EnumThreadWindows(int dwThreadId, EnumThreadDelegate lpfn, IntPtr lParam);
static IEnumerable<IntPtr> EnumerateProcessWindowHandles(Process prc)
{
var handles = new List<IntPtr>();
foreach (ProcessThread thread in prc.Threads)
EnumThreadWindows(thread.Id, (hWnd, lParam) => { handles.Add(hWnd); return true; }, IntPtr.Zero);
return handles;
}
}
public class ProcessSpyData
{
private const uint WM_GETTEXT = 0x000D;
[DllImport("user32.dll", CharSet = CharSet.Auto)]
static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, int wParam, StringBuilder lParam);
[DllImport("user32.dll")]
private static extern bool GetClientRect(IntPtr hWnd, out RECT lpRect);
[StructLayout(LayoutKind.Sequential)]
private struct RECT
{
int left, top, right, bottom;
public Rectangle ToRectangle()
{
return new Rectangle(left, top, right - left, bottom - top);
}
}
[DllImport("user32.dll")]
static extern bool ClientToScreen(IntPtr hWnd, ref Point lpPoint);
public IntPtr WindowHandle { get; private set; }
public string WindowText { get; private set; }
public Rectangle ClientRect { get; private set; }
public Rectangle ScreenPos { get; private set; }
public ProcessSpyData(IntPtr windowHandle)
{
this.WindowHandle = windowHandle;
GetWindowText();
GetWindowSize();
}
private void GetWindowText()
{
StringBuilder message = new StringBuilder(1024);
SendMessage(this.WindowHandle, WM_GETTEXT, message.Capacity, message);
this.WindowText = message.ToString();
}
private void GetWindowSize()
{
var nativeRect = new RECT();
GetClientRect(this.WindowHandle, out nativeRect);
this.ClientRect = nativeRect.ToRectangle();
Point loc = this.ClientRect.Location;
ClientToScreen(this.WindowHandle, ref loc);
this.ScreenPos = new Rectangle(loc, this.ClientRect.Size);
}
}
That should get you started, but you have to be aware if app is using non standard controls then there is no way to get text out of it with this method, and for images maybe you will get better results looking at executable resources.
UPDATE
Geting controls text for various control types (MFC, winforms, Delphi VCL etc.) would be very hard task, but for winforms see excelent Managed Windows API, they even have some sort of spy application in tools, look at that.
What kind of data are you trying to capture?
You may try listening to windows messages or reading the memory.
Depending on how much of these type of tasks you are going to be doing in the future (or how important this one is) you could try investing in something like Ranorex Spy (Ranorex studio is ott).
Link: http://www.ranorex.com/product/tools/ranorex-spy.html
there is no other way than to inject the application you want to inspect. This is how UISpy actually runs. This is also why UISpy should be run with Administrative credential.

Send Message in C#

I'm creating an application that uses a main project that is connected to several different DLLs. From one DLL window I need to be able to open a window in another but the DLL's can't reference each other.
It was suggested to me to use the sendmessage function in the first DLL and have a listener in the main program that directs that message to the appropriate DLL to open it's window.
However I'm not familiar at all with the sendmessage function and am having a lot of diffculty piecing things together from information I'm finding online.
If someone could please show me the correct way (if there is any) to use the sendmessage function and maybe how a listener captures that message that would be amazing. Here is some of the code I've got so far I'm not sure if I'm heading in the right direction.
[DllImport("user32.dll")]
public static extern int FindWindow(string lpClassName, String lpWindowName);
[DllImport("user32.dll")]
public static extern int SendMessage(IntPtr hWnd, int wMsg, IntPtr wParam, IntPtr lParam);
public void button1_Click(object sender, EventArgs e)
{
int WindowToFind = FindWindow(null, "Form1");
}
public static extern int FindWindow(string lpClassName, String lpWindowName);
In order to find the window, you need the class name of the window. Here are some examples:
C#:
const string lpClassName = "Winamp v1.x";
IntPtr hwnd = FindWindow(lpClassName, null);
Example from a program that I made, written in VB:
hParent = FindWindow("TfrmMain", vbNullString)
In order to get the class name of a window, you'll need something called Win Spy
Once you have the handle of the window, you can send messages to it using the SendMessage(IntPtr hWnd, int wMsg, IntPtr wParam, IntPtr lParam) function.
hWnd, here, is the result of the FindWindow function. In the above examples, this will be hwnd and hParent. It tells the SendMessage function which window to send the message to.
The second parameter, wMsg, is a constant that signifies the TYPE of message that you are sending. The message might be a keystroke (e.g. send "the enter key" or "the space bar" to a window), but it might also be a command to close the window (WM_CLOSE), a command to alter the window (hide it, show it, minimize it, alter its title, etc.), a request for information within the window (getting the title, getting text within a text box, etc.), and so on. Some common examples include the following:
Public Const WM_CHAR = &H102
Public Const WM_SETTEXT = &HC
Public Const WM_KEYDOWN = &H100
Public Const WM_KEYUP = &H101
Public Const WM_LBUTTONDOWN = &H201
Public Const WM_LBUTTONUP = &H202
Public Const WM_CLOSE = &H10
Public Const WM_COMMAND = &H111
Public Const WM_CLEAR = &H303
Public Const WM_DESTROY = &H2
Public Const WM_GETTEXT = &HD
Public Const WM_GETTEXTLENGTH = &HE
Public Const WM_LBUTTONDBLCLK = &H203
These can be found with an API viewer (or a simple text editor, such as notepad) by opening (Microsoft Visual Studio Directory)/Common/Tools/WINAPI/winapi32.txt.
The next two parameters are certain details, if they are necessary. In terms of pressing certain keys, they will specify exactly which specific key is to be pressed.
C# example, setting the text of windowHandle with WM_SETTEXT:
x = SendMessage(windowHandle, WM_SETTEXT, new IntPtr(0), m_strURL);
More examples from a program that I made, written in VB, setting a program's icon (ICON_BIG is a constant which can be found in winapi32.txt):
Call SendMessage(hParent, WM_SETICON, ICON_BIG, ByVal hIcon)
Another example from VB, pressing the space key (VK_SPACE is a constant which can be found in winapi32.txt):
Call SendMessage(button%, WM_KEYDOWN, VK_SPACE, 0)
Call SendMessage(button%, WM_KEYUP, VK_SPACE, 0)
VB sending a button click (a left button down, and then up):
Call SendMessage(button%, WM_LBUTTONDOWN, 0, 0&)
Call SendMessage(button%, WM_LBUTTONUP, 0, 0&)
No idea how to set up the listener within a .DLL, but these examples should help in understanding how to send the message.
You are almost there. (note change in the return value of FindWindow declaration). I'd recommend using RegisterWindowMessage in this case so you don't have to worry about the ins and outs of WM_USER.
[DllImport("user32.dll")]
public static extern IntPtr FindWindow(string lpClassName, String lpWindowName);
[DllImport("user32.dll")]
public static extern int SendMessage(IntPtr hWnd, int wMsg, IntPtr wParam, IntPtr lParam);
[DllImport("user32.dll", SetLastError=true, CharSet=CharSet.Auto)]
static extern uint RegisterWindowMessage(string lpString);
public void button1_Click(object sender, EventArgs e)
{
// this would likely go in a constructor because you only need to call it
// once per process to get the id - multiple calls in the same instance
// of a windows session return the same value for a given string
uint id = RegisterWindowMessage("MyUniqueMessageIdentifier");
IntPtr WindowToFind = FindWindow(null, "Form1");
Debug.Assert(WindowToFind != IntPtr.Zero);
SendMessage(WindowToFind, id, IntPtr.Zero, IntPtr.Zero);
}
And then in your Form1 class:
class Form1 : Form
{
[DllImport("user32.dll", SetLastError=true, CharSet=CharSet.Auto)]
static extern uint RegisterWindowMessage(string lpString);
private uint _messageId = RegisterWindowMessage("MyUniqueMessageIdentifier");
protected override void WndProc(ref Message m)
{
if (m.Msg == _messageId)
{
// do stuff
}
base.WndProc(ref m);
}
}
Bear in mind I haven't compiled any of the above so some tweaking may be necessary.
Also bear in mind that other answers warning you away from SendMessage are spot on. It's not the preferred way of inter module communication nowadays and genrally speaking overriding the WndProc and using SendMessage/PostMessage implies a good understanding of how the Win32 message infrastructure works.
But if you want/need to go this route I think the above will get you going in the right direction.
You don't need to send messages.
Add an event to the one form and an event handler to the other. Then you can use a third project which references the other two to attach the event handler to the event. The two DLLs don't need to reference each other for this to work.
It doesn't sound like a good idea to use send message. I think you should try to work around the problem that the DLLs can't reference each other...
Some other options:
Common Assembly
Create another assembly that has some common interfaces that can be implemented by the assemblies.
Reflection
This has all sorts of warnings and drawbacks, but you could use reflection to instantiate / communicate with the forms. This is both slow and runtime dynamic (no static checking of this code at compile time).
Building on Mark Byers's answer.
The 3rd project could be a WCF project, hosted as a Windows Service. If all programs listened to that service, one application could call the service. The service passes the message on to all listening clients and they can perform an action if suitable.
Good WCF videos here - http://msdn.microsoft.com/en-us/netframework/dd728059

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