I need to create some interface to read data from iButton. Actually it work's like that: user applies little pendant with magnet to iButton device -> log in him. User take away pendant - logout.
My problem is that, I know how to relog, by simple:
public static void sp_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
if (sp.ReadLine() == "logout")
{
logoutUser();
}
else
{
//put data into nonstatic textbox from another window
// or raise some event which will listen to changes in data and put string into textbox
}
}
But how can I raise event when data != "logout" (for example A0019293881, as pin code).
You can create your own event, an lauch then in the else clause, then create some method to hear the event an do what you want.
More about events here
Related
Hi I had posted a question along these lines recently but this is now a little more specific to my requirements. So, I have an Application where the user needs to log in. The log in process can take some time so I decided to put up a little animated GIF to show it is doing something. Sounds simple...!!??
I noticed soon that the login process was freezing the animation so I thought, I will put the login process on its own thread. I had countless instances of it referencing objects on the UI Thread so thought I would try the other way round and have the Image display on a new thread. Same issue - so I decided to create a new window containing the image, format it accordingly and display this as a new thread! Simple! That (bit) worked... I click to login, animation appears and disappears onces login is complete. So the Thread variable is set as global one:
Friend g_thLoading As Thread
And when the Login button is clicked I have the following:
g_thLoading = New Thread(AddressOf LoginSplashScreen)
g_thLoading.SetApartmentState(ApartmentState.STA)
g_thLoading.IsBackground = True
g_thLoading.Name = "LoginThread"
g_thLoading.Start()
VerifyLogin() 'Process that takes a while...
g_thLoading.Abort()
Then the method that is called in the new thread:
Sub LoginSplashScreen()
Dim SplashScreenWin As New SplashScreen()
Try
SplashScreenWin.ShowDialog()
System.Windows.Threading.Dispatcher.Run()
Catch ex As Exception
SplashScreenWin.Close()
SplashScreenWin = Nothing
End Try
End Sub
This works - but not if I have to click the button more than once. However If (for example) the user enters the wrong credentials, clicks login (the above processes and completes) they are prompted to re-enter - click the login button again... but this time, the window doesnt display (but oddly does appear in the Task Bar)... Then the application is forced to close (nothing in debug on why that is).
I am confident that the Dialogue Window is closing correctly after the first instance as i) it is no longer in the Task Bar and secondly I have put some checks on the Windows Close event. I am fairly confident that the created Thread is closed after the first instance as I can see it drop off from the Thread Window in Visual Studio... So - I am at a total loss. I have also tried the Join function on the thread but this just hangs the process before it gets to g_thLoading.Abort()
I am open to any advice on how I can go about achieving my end goal... whether it is expanding on what I have done here or another suggestion altogether. I have messed around with the Background Worker but not had much more luck there.
Use the BackgroundWorker class to implement your long running processes. The class allows you to specify code that will run on a background thread (in the DoWork event handler), code that will run during "updates" on the thread that created the BackgroundWorker in the ProgressChanged event handler, and code that will run when the process completes, again on the thread that created the BackgroundWorker in the RunWorkerCompleted event handler.
Using it goes something like this:
private class LoginParameters {
public string Name { get; set; }
public string Password { get; set; }
// Any other properties needed
}
// Make this a property of your form.
BackgroundWorker LoginWorker { get; set; }
// Somewhere in your UI code after the user clicks the "login button"
LoginWorker = new BackgroundWorker();
LoginWorker.WorkerReportsProgress = true;
LoginWorker.WorkerSupportsCancellation = true; // Can set to false if you don't allow the operation to be cancelled.
LoginWorker.DoWorker += DoLogin;
LoginWorker.ProgressChanged += ReportProgress;
LoginWorker.RunWorkerCompleted += LoginFinished;
LoginParameters login = new LoginParameters {
// Code to initialize everything here
};
LoginWorker.RunWorkerAsync(login);
// Put this in the click event handler for the Cancel button, if you have one
if ( LoginWorker != null )
LoginWorker.CancelAsync();
private void DoLogin(object sender, DoWorkEventArgs e) {
BackgroundWorker worker = (BackgroundWorker) sender;
LoginParameters login = (LoginParameters) e.Argument;
// Your logic to process the login goes here. It should periodically do the following to check to see if the user clicked the cancel button:
if ( worker.CancellationPending ) {
e.Cancel = true;
return;
}
// When you want to update the UI, do this:
worker.ReportProgress( percentComplete, objectWithOtherDataToWriteToTheUI );
// When you're done, just return.
}
private void ReportProgress(object sender, ProgressChangedEventArgs e) {
// Your code to extract the data you need to update the display from the arguments & to then update the display goes here. Remember, this runs on the UI thread
}
private void LoginFinished( object sender, RunWorkerCompletedEventArgs e ) {
if (e.Cancelled == true)
// Your code to inform the user of the cancellation here
else if (e.Error != null)
// All unhadgled exceptions throws by the DoWork event handler end up here
// Your code to inform the user of the error here
else {
// Your code to inform the user of the success goes here.
// Remember, this runs on the UI thread.
// I recommend you set the form BackgroundWorker property to null after its finished, as you can't reuse it after its finished.
LoginWorker = null;
}
}
Sorry this is in C# if you're looking for VB.NET, but it shouldn't be hard to translate.
I use wcf service client to submit changes of data for a silverlight project. The correlative codes like this:
public class DispatcherCollection : UpdatableCollection<DocumentDispatcher>
{
public override void SubmitChanges()
{
DocumentServiceClient client = new DocumentServiceClient();
client.NewDocumentCompleted += (s, e) =>
{
// (s as DocumentServiceClient).CloseAsync();
// do something
};
client.UpdateColumnCompleted += (s, e) =>
{
// (s as DocumentServiceClient).CloseAsync();
// do something
};
client.RemoveDocumentCompleted += (s, e) =>
{
// (s as DocumentServiceClient).CloseAsync();
// do something
};
foreach (DocumentDispatcher d in this)
{
if (d.IsNew)
{
// d=>object[] data
client.NewDocumentAsync(data);
d.IsNew=false;
}
else
{
foreach (string propertyName in d.modifiedProperties)
{
client.UpdateColumnAsync(d.ID, GetPropertyValue(propertyName));
}
dd.ClearModifications();
}
}
foreach (DocumentDispatcher dd in removedItems)
{
client.RemoveDocumentAsync(dd.ID);
}
removedItems.Clear();
}
}
Class UpdatableCollection derives from ObserableCollection, and I implemtent logics in class DocumentDispatcher and UpdatableCollection to buffer the changes of data such as new created, property modified and removed. I use SubmitChanges method to submit all changes to server.
Now I am stuck:
1. I am at a loss when to close the client after a bunlde fo async calls. I don't know which callback is the last one.
2. What will happen when a user closes the IE immediately right after clicking the save button (it seems to be done because it runs async but in fact the updating threads are industriously running.)?
You can keep a counter or use an isbusy function to monitor the callbacks from your Async calls - to make sure they all finished.
If the user fires off a request to the WCF service, the WCF service will complete but there will be no call back - as the application will be closed.
I think that there is no wait handle for silverlight asynchornized call brings inconvenience. Here is my experence. I want to check and submit modifications of data which are not expicitly submitted when browser is closing. I have implemented codes in App_Exit like this:
private void Application_Exit(object sender, EventArgs e)
{
Document doc = EDPViewModel.CurrentViewModel.Document;
if (doc != null) new ServiceClient().SubmitChangesAsync(doc);
}
provided that in the SubmitChangesAsync method, not submitted modifications of doc are found out and submitted. Therefore, because of the asynchronized running features, while the service invoking is being sent, the application is yet immediately closed. And that will dispose related resouces of the application, including Service Invoking Tasks. So the codes above work not. I hope so eagerly that somewhere exists a mechanism, which can export a wait handle from silverlight asynchronized call, so that I can update the above codes whith this:
private void Application_Exit(object sender, EventArgs e)
{
Document doc = EDPViewModel.CurrentViewModel.Document;
if (doc != null)
{
Task t = new TaskFactory().StartNew(() => new ServiceClient().SubmitChangesAsync(doc));
t.Wait();
}
}
With wait operation I can really be sure that all modifications are really definitely submitted. So is there any similar pattern that can be used in silverlight?
It's for me a good news, as you put it, that calls could work like the mode "requesting and forgetting". So I needn' to worry too much about data losing during submitting.
To ensure all service calls are sent out before application is closed, I think, counter is a simple and effient idea. I will try to implement it in my project.
Thank you for your help!
I'm using C# VS2008, WinForm application
I have a checkedlistbox control on my form (win-form application)
In the code I check some items in checkedlistbox using the SetItemChecked(index, false) method and it raise the event ItemCheck.
I also allow the user to check items in that checkedlistbox and it also raise the event ItemCheck when the user check or uncheck an item.
How can I find in the ItemCheck event how this event occur (via code or via user keyboard/mouse input)?
Thanks.
I think that there is no a simple way to differentiate the situation using code.
The only thing that comes to mind is through the use of a global form variable:
public class Form1:Form
{
bool _isCodeClick = false;
.....
// Somewhere in your code
_isCodeClick = true;
checkedListBox1.SetItemChecked(index, true);
_isCodeClick = false;
.....
private void CheckedListBox1_ItemCheck(Object sender, ItemCheckEventArgs e)
{
if(_isCodeClick == true)
{
// Do processing for click by code
}
else
{
// Do processing for click by user
}
}
}
If you go for this solution remember to take additional steps to correctly trap exceptions that could bypass the reset of the global variable to the false state.
Probably using advanced manipulation of keyboard and mouse events you could reach a reasonable way to identify what has caused the ItemCheck event, but sometime some solutions are too complex and not worth it.
EDIT: Reviewing my answer I feel the need to add a little change to reduce the maintaining problems that this esponse implies.
The code that set the boolean variable and call the SetItemChecked should be encapsulated in a separate function like this
private void SetItemCheckedFromCode(int index, bool toSet)
{
try
{
_isCodeClick = true;
checkedListBox1.SetItemChecked(index, true);
}
finally
{
_isCodeClick = false;
}
}
Is there a way to log all of the clicks in a Win Forms application? I'd like to intercept clicks and record the action and the name of the control that caused it.
Is this possible?
Thanks in advance.
UPDATE: I'm looking for an application wide solution, is there no way to add a listener to the windows event queue (or what ever it is called)?
You can do this by having your app's main form implement the IMessageFilter interface. You can screen the Window messages it gets and look for clicks. For example:
public partial class Form1 : Form, IMessageFilter {
public Form1() {
InitializeComponent();
Application.AddMessageFilter(this);
this.FormClosed += (o, e) => Application.RemoveMessageFilter(this);
}
public bool PreFilterMessage(ref Message m) {
if (m.Msg == 0x201 || m.Msg == 0x203) { // Trap left click + double-click
string name = "Unknown";
Control ctl = Control.FromHandle(m.HWnd);
if (ctl != null) name = ctl.Name;
Point pos = new Point(m.LParam.ToInt32());
Console.WriteLine("Click {0} at {1}", name, pos);
}
return false;
}
}
Note that this logs all clicks in any window of your app.
You could use Spy++ or WinSpy++ to achieve this.
alt text http://www.catch22.net/sites/default/files/images/winspy1.img_assist_custom.jpg
But I'm not sure how you can achieve the same thing yourself. If it's possible you'd need to do it via a low-level Windows API hook or a message handler that gives you access to all the message in your applications queue.
Well, you could subscribe to the Click or MouseDown event of every control on the form.
use MouseEventArgs like this:
private void Form_MouseDown(object sender, System.WinForms.MouseEventArgs e)
{
switch (e.Button)
{
case MouseButtons.Left:
MessageBox.Show(this,"Left Button Click");
break;
case MouseButtons.Right:
MessageBox.Show(this,"Right Button Click" );
break;
case MouseButtons.Middle:
break;
default:
break;
}
EventLog.WriteEntry("source", e.X.ToString() + " " + e.Y.ToString()); //or your own Log function
}
The NunitForms test project has a recorder application that watches for this and many other events. The code is very clever and worth a good look. It's a ThoughtWorks project.
That's the rolls Royce solution though!...
Try recursively walking the Controls collection of the form and subscibe to the event based on the type.
PK :-)
In my WPF app (csharp) I have an event handler that when triggered will open a new window (window B) of the application and display some data. However, when the event is triggered again, if the new window (window B) is still open, I don't want to spawn another instance of window B but just update the data being displayed in the current instance. So the question is: How to detect if window B is already and only open if it is not already, otherwise just update the data?
I found the Application.Current.Window collection but somehow that isn't working for me yet. Ideas?
You could create a LoadWindow() method in WindowB that you can call to load (or refresh) the data & that will work regardless of if the window is already open or not. Have it take a delegate to call when this window gets closed:
private Action ParentCallbackOnClose;
public void LoadWindow( Action parentCallbackOnClose ) {
// load the data (set the DataContext or whatever)
ParentCallbackOnClose = parentCallbackOnClose;
// Open the window and activate/bring to the foreground
Show( );
Activate( );
}
and have your window closed event call the close delegate:
private void WindowClosed( object sender, EventArgs e ) {
ParentCallbackOnClose.Invoke( );
}
Now, from your class that opens Window B, have it hold onto that instance it opens, so that if WindowB is already open when someone tries to reload it, it just calls LoadWindow on the existing instance. Something like...
private WindowB WinB;
private void LoadWindowB(Content content)
{
if (WinB == null ){
WinB = new WindowB( );
}
WinB.LoadWindow(content, WindowBClosed);
}
And then you can just have it null out WinB on that close callback so if WinB is closed, then the next time LoadWindowB() is called it will create a new instance of it:
private void WindowBClosed( ){
WinB = null;
}
Since this is the first link Google listed, which posted several years ago, for a solution to check if a Window is already open, I'll post my answer, for others, which I find easier to implement. The ChildWindow is only called from MainWindow so no other Window will need to do any checks.
private void OpenChildWindow()
{
if (this.OwnedWindows.OfType<ChildWindow>().Count() > 0)
{
ChildWindow Win = this.OwnedWindows.OfType<ChildWindow>().First();
Win.Activate();
}
else
{
ChildWindow Win = new ChildWindow();
Win.Owner = this;
Win.Show();
}
}
There is an old school way to do this using an interface. I see this in Java a lot as a way to compensate for not having delegates (correct me if I am wrong). This method will allow you to check if there is a window already open (of any kind). The original response works very well, but you can also do it the following way:
Create the interface
public interface IWindowTracker
{
void WindowIsOpened();
void WindowIsClosed();
}
Implement the interface on the parent (from where you are opening):
public partial class MainWindow : Window, IWindowTracker
In your constructor, accept an object that is of the IwindowTracker interface. Save the instance for future use
IWindowTracker windowTracker;
public ProjectManager(IWindowTracker parentWindowTracker)
{
windowTracker = parentWindowTracker;
InitializeComponent();
}
Setup the calls to the window tracker object
protected override void OnActivated(EventArgs e)
{
windowTracker.WindowIsOpened();
base.OnActivated(e);
}
protected override void OnClosed(EventArgs e)
{
windowTracker.WindowIsClosed();
base.OnClosed(e);
}
and finally implement the IWindowTracker in your parent WPF window
bool windowIsOpen = false;
public void WindowIsOpened()
{
windowIsOpen = true;
}
public void WindowIsClosed()
{
windowIsOpen = false;
}
This will allow you to keep track of if the window is still open and if it is, there is no need to open a new instance of it:
if (!windowIsOpen)
{
remoteProjectManager = new ProjectManager(this);
remoteProjectManager.Show();
}
remoteProjectManager.Focus();
Calling show() on a closed window seems to throw an exception, so my guess is that there is some other way or that if you have closed the window, the window is technically "destroyed"
The nice thing to this is that I can detect if the window is still open and focus on it (so that it comes to the front again).
NOTE: There is a draw back to this, in that in this setup it limits you to opening only one window at a time (assuming that all your windows are implemented like this). In my case, I only ever want to have one window open besides the main window.
You might also want to check if your window is null or not, considering that it probably isn't the only window you will have to open.
edit: oops, my answer is specific to Windows Forms. i just now saw the WPF mention. i'm not sure what the specific code would be for WPF, but i would imagine that it's not all that different conceptually. I think in WPF the property is called IsVisible instead of Visible
You could hold on to the instance of your window (or make it a Singleton) and then when you need to determine if it is visible or not, check it's Visible property.
for example:
if(myWindow.Visible){
myWindow.Hide();
}else{
myWindow.Show();
}
This article it the best I found for passing data between WPF pages. The author used KISS approach to provide a simple solution.