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Progress Bar for the method present inside another class C# WPF [duplicate]

-Updated--14/10 also asked this question
To give some clear idea of what is going on and taking into account the comments and from this article here
What I really want to do now is invoke a new form with a progress bar on it and have that run and animate whilst my back ground thread runs my long process to the database and then invoke a close form event
The background worker is set up here
public partial class MainWindow : Window
{
//Declare background workers
BackgroundWorker bw = new BackgroundWorker();
BackgroundWorker bwLoadCSV = new BackgroundWorker();
BackgroundWorker bwProgressBar = new BackgroundWorker();
Then delegates added here
public MainWindow()
{
bwLoadCSV.WorkerReportsProgress = true;
bwLoadCSV.WorkerSupportsCancellation = true;
bwLoadCSV.DoWork += new DoWorkEventHandler(bwLoadCSV_DoWork);
bwLoadCSV.ProgressChanged += new ProgressChangedEventHandler(bwLoadCSV_ProgressChanged);
bwLoadCSV.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bwLoadCSV_RunWorkerCompleted);
The call is made here from the main window class
private void CSV_Load_Click(object sender, RoutedEventArgs e)
///Function to read csv into datagrid
///
{
//Turn Cursor to wait
System.Windows.Forms.Cursor.Current = System.Windows.Forms.Cursors.WaitCursor;
//Test connection to sql server
if (CHHoursDataProvider.IsDatabaseOnline() == false)
{
System.Windows.Forms.MessageBox.Show("Can not establish contact with sql server" + "\n" + "Contact IT", "Connection Error");
//Set UI picture
return;
}
//Set a control to update the user here
tbLoadDgStat.Visibility = Visibility.Visible;
tbLoadDgStat.Text = "Getting data templete from Database...";
string FilePath = txFilePath.Text;
if (bwLoadCSV.IsBusy != true)
{
//load the context object with parameters for Background worker
bwCSVLoadContext Context = new bwCSVLoadContext();
Context.Site = cBChSite.Text;
Context.FilePath = txFilePath.Text;
Context.FileName = fileTest;
Context.Wageyear = cbWageYear.Text;
Context.Startdate = ((DateTime)dpStartDate.SelectedDate);
Context.Enddate = ((DateTime)dpEndDate.SelectedDate);
bwLoadCSV.RunWorkerAsync(Context);
}
The background worker do work is
private void bwLoadCSV_DoWork(object sender, DoWorkEventArgs e)
{
BackgroundWorker worker = sender as BackgroundWorker;
bwCSVLoadContext Context = e.Argument as bwCSVLoadContext;
worker.ReportProgress((10));
if ((worker.CancellationPending == true))
{
e.Cancel = true;
}
else
{
// Perform a time consuming operation and report progress load csv into datagrid.
To report the background work I do this. This is where I am trying to load a new form call ProgressDialog which has a progress bar on it, which I am try set to Indeterminable so it just "swishes" across my ProgressDialoge form to show the user something is still going on. I have used the reporter part of the background work because I believe it has access to the main window thread and I am hoping that the invoke method is then called from the main window thread, but I am not really sure
Here is the reporter
private void bwLoadCSV_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
this.Dispatcher.Invoke((MethodInvoker)delegate { tbLoadDgStat.Visibility = Visibility.Visible; });
//tbLoadDgStat.Visibility = Visibility.Visible;
//this.progressBar1.Value = e.ProgressPercentage;//This works but pauses on long steps
if (e.ProgressPercentage == 10)
{
//Try to open a new form with a class ProgressDialog and set the progressbar
// on the frm to IsIndeterminate=true
//THIS IS NOT WORKING
this.Dispatcher.BeginInvoke (new Action(() =>
{ ProgressDialog progressDialog = new ProgressDialog();
progressDialog.SetIndeterminate(true);
}));
//this updates the main form OK
this.Dispatcher.Invoke((MethodInvoker)delegate { tbLoadDgStat.Text = "Getting data templete from Database..."; });
}
else if (e.ProgressPercentage == 20)
{
this.Dispatcher.Invoke((MethodInvoker)delegate { tbLoadDgStat.Text = "Data template retrieved..."; });
}
else
{
if (e.ProgressPercentage % 10 == 0)
{
this.Dispatcher.Invoke((MethodInvoker)delegate { tbLoadDgStat.Text = "Adding Data..." + e.ProgressPercentage.ToString() + "%"; });
}
}
Lastly the xaml for the ProgressDialog Form and it's class
<Window x:Class="Test_Read_CSV.ProgressDialog"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Progress Dialog" Height="115" Width="306" Name="ProgressPopup">
<Grid>
<ProgressBar Height="31" HorizontalAlignment="Left" Margin="12,33,0,0" Name="progressBar1" VerticalAlignment="Top" Width="250" />
<TextBox Height="23" HorizontalAlignment="Left" Margin="7,4,0,0" Name="tbEvent" VerticalAlignment="Top" Width="254" IsReadOnly="True" IsEnabled="False" />
</Grid>
class
/// <summary>
/// Interaction logic for ProgressDialog.xaml
/// </summary>
public partial class ProgressDialog : Window
{
public ProgressDialog()
{
WindowStartupLocation = WindowStartupLocation.CenterScreen;
InitializeComponent();
}
public ProgressDialog(String Purpose)
{
InitializeComponent();
tbEvent.Text = Purpose;
WindowStartupLocation = WindowStartupLocation.CenterScreen;
}
public void UpdateProgress(int progress)
{
progressBar1.Dispatcher.BeginInvoke(
new Action(() =>
{
progressBar1.Value = progress;
}
));
}
public void SetIndeterminate(bool isIndeterminate)
{
progressBar1.Dispatcher.BeginInvoke(
new Action(() =>
{
if (isIndeterminate)
{
progressBar1.IsIndeterminate = true;
}
else
{
progressBar1.IsIndeterminate = false;
}
}
));
}
}
}
I have read and done a number of tutorial on background worker and even some on threads but can not seem to get the result I want
The idea is I have two long processes where I am either getting a datatable clone from my remote bd or I am updating the db from my wpf application (.net 4). While the process is running I want a progress bar control and to update it, for the obivous reason of making it clear that some work is going on. So I did the usual report progress routines in the background worker and it works....However, in my dowork thread I have this command
CHHoursDataProvider CH = new CHHoursDataProvider();
oTable = CH.CloneCHHours();
this where the communication with db is and this command takes a good 60 - 90 secs on a vpn remote connection so even if I do this
CHHoursDataProvider CH = new CHHoursDataProvider();
worker.ReportProgress((10));
oTable = CH.CloneCHHours();
worker.ReportProgress((20));
The main window still looks frozen and like it has crashed!
So all I want to do is at the start of the call to the background work is set a progressbar running and leave it running till the end of the task. This is all I need to do to finish my first ever project and after three days I still can not get my head around it!
So I have tried the follow
In the bw progress changed and in the main window class
this.progressBar2.IsIndeterminate = true;
However the animation does not start till the Dowork thread has finished.
I then created another background worker to do update the progressbar2, which linked to a button on the main window was ok, but as soon as I tried to use it from the other background worker or from the main window class did not run till the dowork thread had completed on the first background worker
I then tried to follow a invoke method but REALLY got lost on that!
So can anyone help I can guess it is something to do with threading and working on the wrong thread etc but what I do about it I have no clue.
I can post more code as needed
Ian

As you haven't shown your full BackgroundWorker code, I can't tell if you have implemented it correctly. As such, all I can do is to show you a simple working example of updating a ProgressBar control:
UserControl XAML:
<UserControl x:Class="WpfApplication1.Views.TestView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300" Loaded="UserControl_Loaded">
<ProgressBar x:Name="progressBar" Height="25" Margin="20" Minimum="0"
Maximum="50" />
</UserControl>
MainWindow XAML:
<Window x:Class="WpfApplication1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:Views="clr-namespace:WpfApplication1.Views"
Title="MainWindow" Height="350" Width="525">
<Views:TestView />
</Window>
UserControl code behind:
using System.ComponentModel;
using System.Threading;
using System.Windows;
using System.Windows.Controls;
namespace WpfApplication1.Views
{
public partial class TestView : UserControl
{
private BackgroundWorker backgroundWorker = new BackgroundWorker();
public TestView()
{
InitializeComponent();
backgroundWorker.WorkerReportsProgress = true;
backgroundWorker.ProgressChanged += ProgressChanged;
backgroundWorker.DoWork += DoWork;
// not required for this question, but is a helpful event to handle
backgroundWorker.RunWorkerCompleted += BackgroundWorker_RunWorkerCompleted;
}
private void UserControl_Loaded(object sender, RoutedEventArgs e)
{
backgroundWorker.RunWorkerAsync();
}
private void DoWork(object sender, DoWorkEventArgs e)
{
for (int i = 0; i <= 100; i++)
{
// Simulate long running work
Thread.Sleep(100);
backgroundWorker.ReportProgress(i);
}
}
private void ProgressChanged(object sender, ProgressChangedEventArgs e)
{
// This is called on the UI thread when ReportProgress method is called
progressBar.Value = e.ProgressPercentage;
}
private void BackgroundWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
// This is called on the UI thread when the DoWork method completes
// so it's a good place to hide busy indicators, or put clean up code
}
}
}

Want to run Progess-Bar continuously in UI till we receive the service response

I want to assign a new thread to a continuous Progress-bar in WPF application, so that it will run continuously after clicking on UI button till I receive the service response.
I did a code like below, but progress-bar (MclarenServerCecksProgressBar) it seems not working at all
MclarenServerCecksProgressBar.Visibility = Visibility.Visible;
var uiThread = new Thread(() =>
{
progressBarDisptacher = MclarenServerCecksProgressBar.Dispatcher;
// allowing the main UI thread to proceed
System.Windows.Threading.Dispatcher.Run();
});
uiThread.SetApartmentState(ApartmentState.STA);
uiThread.IsBackground = true;
uiThread.Start();
string[] servicesss = getServices(servername,server);
DataTable dtd = esd.getListOfServices(servername, usrid.Text.ToString(),
userpass.Password.ToString(), servicesss);
MclarenServerCecksProgressBar.Visibility = Visibility.Hidden;
Please arrange to suggest me to achieve this, any other pointers will be much helpful.

I don't get how in your code progressbar value sets. Also I do not quite understand why are you using this hacking with threads. I made an example how I am doing this with progress-bars, if I understand your question right.
<Window x:Class="WpfApplication5.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow"
Height="350"
Width="525">
<Grid>
<ProgressBar Height="10"
HorizontalAlignment="Left"
Margin="12,12,0,0"
Name="progressBar1"
VerticalAlignment="Top"
Width="100"
Visibility="Hidden" />
<Button Content="Button"
Height="23"
HorizontalAlignment="Left"
Margin="30,54,0,0"
Name="button1"
VerticalAlignment="Top"
Width="75"
Click="button1_Click" />
</Grid>
</Window>
using System;
using System.Threading;
using System.Windows;
namespace WpfApplication5 {
public partial class MainWindow : Window {
public MainWindow() {
InitializeComponent();
}
void button1_Click(object sender, RoutedEventArgs e) {
progressBar1.Visibility = Visibility.Visible;
Action method = () => {
Action<int> method2 = (val) => {
progressBar1.Value = val;
};
for (int i = 0 ; i < 10 ; i++) {
Thread.Sleep(500);
Dispatcher.BeginInvoke(method2, i * 10);
}
Action method3 = () => {
progressBar1.Visibility = Visibility.Hidden;
};
Dispatcher.BeginInvoke(method3);
};
method.BeginInvoke(null, null);
}
}
}

A WPF UI only ever has one UI thread that you can use for communication - the dispatcher thread. All your background tasks can be done on whatever threads you like, as long as the calls that interact with the UI object are done via the UI dispatcher. Sending calls through this dispatcher is a common task, so the Dispatcher property is provided on each WPF object.
I would approach the problem like this:
private void button2_Click(object sender, RoutedEventArgs e)
{
// Currently running on the WPF thread so the WPF property can be set directly
this.progressBar1.Visibility = System.Windows.Visibility.Visible;
// Create a new thread to do the long running task
Thread worker = new Thread(() =>
{
WebService.DoSomethingThatTakesAges();
// When the above call has completed, update the UI on its dispatcher thread
this.progressBar1.Dispatcher.BeginInvoke(new Action(() =>
{
this.progressBar1.Visibility = System.Windows.Visibility.Hidden;
}));
});
worker.Start();
}
It's probably better to use the System.Threading.Tasks namespace to create Tasks with TaskSchedulers rather than create threads directly, but the principle is the same.

Finaly I have achieved this by doing some trick. I have used delegate with DependencyProperty and Dispatacher to update the Progressbar, any way this works for me after a long time with various tries, see the code that I did like below
private delegate void UpdateProgressBarDelegate(
System.Windows.DependencyProperty dp, Object value);
private void startProgessBar(string controlname)
{
MclarenServerCecksProgressBar.Visibility = Visibility.Visible;
//Stores the value of the ProgressBar
//Create a new instance of our ProgressBar Delegate that points
// to the ProgressBar's SetValue method.
UpdateProgressBarDelegate updatePbDelegate =
new UpdateProgressBarDelegate(MclarenServerCecksProgressBar.SetValue);
bool _status = true;
int flag = 0;
double value = 0;
do
{
/*Update the Value of the ProgressBar: */
Dispatcher.Invoke(updatePbDelegate,
System.Windows.Threading.DispatcherPriority.Background,
new object[] { System.Windows.Controls.ProgressBar.ValueProperty, value });
if (flag == 0)
{
flag == 1
_status = processesServices(controlname);
}
if (_status == false)
{
MclarenServerCecksProgressBar.Visibility = Visibility.Hidden;
}
}
while (_status);
}
It might be dirty anyway to fix it that I was looking for running the progessbar till I receive a response from a function, any other suggestion to improve this way would be much appriciated.
Welcome for any suggestion and assistance to improve this.

How to update UI from another thread running in another class

I am currently writing my first program on C# and I am extremely new to the language (used to only work with C so far). I have done a lot of research, but all answers were too general and I simply couldn't get it t work.
So here my (very common) problem:
I have a WPF application which takes inputs from a few textboxes filled by the user and then uses that to do a lot of calculations with them. They should take around 2-3 minutes, so I would like to update a progress bar and a textblock telling me what the current status is.
Also I need to store the UI inputs from the user and give them to the thread, so I have a third class, which I use to create an object and would like to pass this object to the background thread.
Obviously I would run the calculations in another thread, so the UI doesn't freeze, but I don't know how to update the UI, since all the calculation methods are part of another class.
After a lot of reasearch I think the best method to go with would be using dispatchers and TPL and not a backgroundworker, but honestly I am not sure how they work and after around 20 hours of trial and error with other answers, I decided to ask a question myself.
Here a very simple structure of my program:
public partial class MainWindow : Window
{
public MainWindow()
{
Initialize Component();
}
private void startCalc(object sender, RoutedEventArgs e)
{
inputValues input = new inputValues();
calcClass calculations = new calcClass();
try
{
input.pota = Convert.ToDouble(aVar.Text);
input.potb = Convert.ToDouble(bVar.Text);
input.potc = Convert.ToDouble(cVar.Text);
input.potd = Convert.ToDouble(dVar.Text);
input.potf = Convert.ToDouble(fVar.Text);
input.potA = Convert.ToDouble(AVar.Text);
input.potB = Convert.ToDouble(BVar.Text);
input.initStart = Convert.ToDouble(initStart.Text);
input.initEnd = Convert.ToDouble(initEnd.Text);
input.inita = Convert.ToDouble(inita.Text);
input.initb = Convert.ToDouble(initb.Text);
input.initc = Convert.ToDouble(initb.Text);
}
catch
{
MessageBox.Show("Some input values are not of the expected Type.", "Wrong Input", MessageBoxButton.OK, MessageBoxImage.Error);
}
Thread calcthread = new Thread(new ParameterizedThreadStart(calculations.testMethod);
calcthread.Start(input);
}
public class inputValues
{
public double pota, potb, potc, potd, potf, potA, potB;
public double initStart, initEnd, inita, initb, initc;
}
public class calcClass
{
public void testmethod(inputValues input)
{
Thread.CurrentThread.Priority = ThreadPriority.Lowest;
int i;
//the input object will be used somehow, but that doesn't matter for my problem
for (i = 0; i < 1000; i++)
{
Thread.Sleep(10);
}
}
}
I would be very grateful if someone had a simple explanation how to update the UI from inside the testmethod. Since I am new to C# and object oriented programming, too complicated answers I will very likely not understand, I'll do my best though.
Also if someone has a better idea in general (maybe using backgroundworker or anything else) I am open to see it.

First you need to use Dispatcher.Invoke to change the UI from another thread and to do that from another class, you can use events.
Then you can register to that event(s) in the main class and Dispatch the changes to the UI and in the calculation class you throw the event when you want to notify the UI:
class MainWindow : Window
{
private void startCalc()
{
//your code
CalcClass calc = new CalcClass();
calc.ProgressUpdate += (s, e) => {
Dispatcher.Invoke((Action)delegate() { /* update UI */ });
};
Thread calcthread = new Thread(new ParameterizedThreadStart(calc.testMethod));
calcthread.Start(input);
}
}
class CalcClass
{
public event EventHandler ProgressUpdate;
public void testMethod(object input)
{
//part 1
if(ProgressUpdate != null)
ProgressUpdate(this, new YourEventArgs(status));
//part 2
}
}
UPDATE:
As it seems this is still an often visited question and answer I want to update this answer with how I would do it now (with .NET 4.5) - this is a little longer as I will show some different possibilities:
class MainWindow : Window
{
Task calcTask = null;
void buttonStartCalc_Clicked(object sender, EventArgs e) { StartCalc(); } // #1
async void buttonDoCalc_Clicked(object sender, EventArgs e) // #2
{
await CalcAsync(); // #2
}
void StartCalc()
{
var calc = PrepareCalc();
calcTask = Task.Run(() => calc.TestMethod(input)); // #3
}
Task CalcAsync()
{
var calc = PrepareCalc();
return Task.Run(() => calc.TestMethod(input)); // #4
}
CalcClass PrepareCalc()
{
//your code
var calc = new CalcClass();
calc.ProgressUpdate += (s, e) => Dispatcher.Invoke((Action)delegate()
{
// update UI
});
return calc;
}
}
class CalcClass
{
public event EventHandler<EventArgs<YourStatus>> ProgressUpdate; // #5
public TestMethod(InputValues input)
{
//part 1
ProgressUpdate.Raise(this, status); // #6 - status is of type YourStatus
// alternative version to the extension for C# 6+:
ProgressUpdate?.Invoke(this, new EventArgs<YourStatus>(status));
//part 2
}
}
static class EventExtensions
{
public static void Raise<T>(this EventHandler<EventArgs<T>> theEvent,
object sender, T args)
{
if (theEvent != null)
theEvent(sender, new EventArgs<T>(args));
}
}
#1) How to start the "synchronous" calculations and run them in the background
#2) How to start it "asynchronous" and "await it": Here the calculation is executed and completed before the method returns, but because of the async/await the UI is not blocked (BTW: such event handlers are the only valid usages of async void as the event handler must return void - use async Task in all other cases)
#3) Instead of a new Thread we now use a Task. To later be able to check its (successfull) completion we save it in the global calcTask member. In the background this also starts a new thread and runs the action there, but it is much easier to handle and has some other benefits.
#4) Here we also start the action, but this time we return the task, so the "async event handler" can "await it". We could also create async Task CalcAsync() and then await Task.Run(() => calc.TestMethod(input)).ConfigureAwait(false); (FYI: the ConfigureAwait(false) is to avoid deadlocks, you should read up on this if you use async/await as it would be to much to explain here) which would result in the same workflow, but as the Task.Run is the only "awaitable operation" and is the last one we can simply return the task and save one context switch, which saves some execution time.
#5) Here I now use a "strongly typed generic event" so we can pass and receive our "status object" easily
#6) Here I use the extension defined below, which (aside from ease of use) solve the possible race condition in the old example. There it could have happened that the event got null after the if-check, but before the call if the event handler was removed in another thread at just that moment. This can't happen here, as the extensions gets a "copy" of the event delegate and in the same situation the handler is still registered inside the Raise method.

I am going to throw you a curve ball here. If I have said it once I have said it a hundred times. Marshaling operations like Invoke or BeginInvoke are not always the best methods for updating the UI with worker thread progress.
In this case it usually works better to have the worker thread publish its progress information to a shared data structure that the UI thread then polls at regular intervals. This has several advantages.
It breaks the tight coupling between the UI and worker thread that Invoke imposes.
The UI thread gets to dictate when the UI controls get updated...the way it should be anyway when you really think about it.
There is no risk of overrunning the UI message queue as would be the case if BeginInvoke were used from the worker thread.
The worker thread does not have to wait for a response from the UI thread as would be the case with Invoke.
You get more throughput on both the UI and worker threads.
Invoke and BeginInvoke are expensive operations.
So in your calcClass create a data structure that will hold the progress information.
public class calcClass
{
private double percentComplete = 0;
public double PercentComplete
{
get
{
// Do a thread-safe read here.
return Interlocked.CompareExchange(ref percentComplete, 0, 0);
}
}
public testMethod(object input)
{
int count = 1000;
for (int i = 0; i < count; i++)
{
Thread.Sleep(10);
double newvalue = ((double)i + 1) / (double)count;
Interlocked.Exchange(ref percentComplete, newvalue);
}
}
}
Then in your MainWindow class use a DispatcherTimer to periodically poll the progress information. Configure the DispatcherTimer to raise the Tick event on whatever interval is most appropriate for your situation.
public partial class MainWindow : Window
{
public void YourDispatcherTimer_Tick(object sender, EventArgs args)
{
YourProgressBar.Value = calculation.PercentComplete;
}
}

You're right that you should use the Dispatcher to update controls on the UI thread, and also right that long-running processes should not run on the UI thread. Even if you run the long-running process asynchronously on the UI thread, it can still cause performance issues.
It should be noted that Dispatcher.CurrentDispatcher will return the dispatcher for the current thread, not necessarily the UI thread. I think you can use Application.Current.Dispatcher to get a reference to the UI thread's dispatcher if that's available to you, but if not you'll have to pass the UI dispatcher in to your background thread.
Typically I use the Task Parallel Library for threading operations instead of a BackgroundWorker. I just find it easier to use.
For example,
Task.Factory.StartNew(() =>
SomeObject.RunLongProcess(someDataObject));
where
void RunLongProcess(SomeViewModel someDataObject)
{
for (int i = 0; i <= 1000; i++)
{
Thread.Sleep(10);
// Update every 10 executions
if (i % 10 == 0)
{
// Send message to UI thread
Application.Current.Dispatcher.BeginInvoke(
DispatcherPriority.Normal,
(Action)(() => someDataObject.ProgressValue = (i / 1000)));
}
}
}

Everything that interacts with the UI must be called in the UI thread (unless it is a frozen object). To do that, you can use the dispatcher.
var disp = /* Get the UI dispatcher, each WPF object has a dispatcher which you can query*/
disp.BeginInvoke(DispatcherPriority.Normal,
(Action)(() => /*Do your UI Stuff here*/));
I use BeginInvoke here, usually a backgroundworker doesn't need to wait that the UI updates. If you want to wait, you can use Invoke. But you should be careful not to call BeginInvoke to fast to often, this can get really nasty.
By the way, The BackgroundWorker class helps with this kind of taks. It allows Reporting changes, like a percentage and dispatches this automatically from the Background thread into the ui thread. For the most thread <> update ui tasks the BackgroundWorker is a great tool.

If this is a long calculation then I would go background worker. It has progress support. It also has support for cancel.
http://msdn.microsoft.com/en-us/library/cc221403(v=VS.95).aspx
Here I have a TextBox bound to contents.
private void backgroundWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
Debug.Write("backgroundWorker_RunWorkerCompleted");
if (e.Cancelled)
{
contents = "Cancelled get contents.";
NotifyPropertyChanged("Contents");
}
else if (e.Error != null)
{
contents = "An Error Occured in get contents";
NotifyPropertyChanged("Contents");
}
else
{
contents = (string)e.Result;
if (contentTabSelectd) NotifyPropertyChanged("Contents");
}
}

You are going to have to come back to your main thread (also called UI thread) in order to update the UI.
Any other thread trying to update your UI will just cause exceptions to be thrown all over the place.
So because you are in WPF, you can use the Dispatcher and more specifically a beginInvoke on this dispatcher. This will allow you to execute what needs done (typically Update the UI) in the UI thread.
You migh also want to "register" the UI in your business, by maintaining a reference to a control/form, so you can use its dispatcher.

Thank God, Microsoft got that figured out in WPF :)
Every Control, like a progress bar, button, form, etc. has a Dispatcher on it. You can give the Dispatcher an Action that needs to be performed, and it will automatically call it on the correct thread (an Action is like a function delegate).
You can find an example here.
Of course, you'll have to have the control accessible from other classes, e.g. by making it public and handing a reference to the Window to your other class, or maybe by passing a reference only to the progress bar.

Felt the need to add this better answer, as nothing except BackgroundWorker seemed to help me, and the answer dealing with that thus far was woefully incomplete. This is how you would update a XAML page called MainWindow that has an Image tag like this:
<Image Name="imgNtwkInd" Source="Images/network_on.jpg" Width="50" />
with a BackgroundWorker process to show if you are connected to the network or not:
using System.ComponentModel;
using System.Windows;
using System.Windows.Controls;
public partial class MainWindow : Window
{
private BackgroundWorker bw = new BackgroundWorker();
public MainWindow()
{
InitializeComponent();
// Set up background worker to allow progress reporting and cancellation
bw.WorkerReportsProgress = true;
bw.WorkerSupportsCancellation = true;
// This is your main work process that records progress
bw.DoWork += new DoWorkEventHandler(SomeClass.DoWork);
// This will update your page based on that progress
bw.ProgressChanged += new ProgressChangedEventHandler(bw_ProgressChanged);
// This starts your background worker and "DoWork()"
bw.RunWorkerAsync();
// When this page closes, this will run and cancel your background worker
this.Closing += new CancelEventHandler(Page_Unload);
}
private void bw_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
BitmapImage bImg = new BitmapImage();
bool connected = false;
string response = e.ProgressPercentage.ToString(); // will either be 1 or 0 for true/false -- this is the result recorded in DoWork()
if (response == "1")
connected = true;
// Do something with the result we got
if (!connected)
{
bImg.BeginInit();
bImg.UriSource = new Uri("Images/network_off.jpg", UriKind.Relative);
bImg.EndInit();
imgNtwkInd.Source = bImg;
}
else
{
bImg.BeginInit();
bImg.UriSource = new Uri("Images/network_on.jpg", UriKind.Relative);
bImg.EndInit();
imgNtwkInd.Source = bImg;
}
}
private void Page_Unload(object sender, CancelEventArgs e)
{
bw.CancelAsync(); // stops the background worker when unloading the page
}
}
public class SomeClass
{
public static bool connected = false;
public void DoWork(object sender, DoWorkEventArgs e)
{
BackgroundWorker bw = sender as BackgroundWorker;
int i = 0;
do
{
connected = CheckConn(); // do some task and get the result
if (bw.CancellationPending == true)
{
e.Cancel = true;
break;
}
else
{
Thread.Sleep(1000);
// Record your result here
if (connected)
bw.ReportProgress(1);
else
bw.ReportProgress(0);
}
}
while (i == 0);
}
private static bool CheckConn()
{
bool conn = false;
Ping png = new Ping();
string host = "SomeComputerNameHere";
try
{
PingReply pngReply = png.Send(host);
if (pngReply.Status == IPStatus.Success)
conn = true;
}
catch (PingException ex)
{
// write exception to log
}
return conn;
}
}
For more information: https://msdn.microsoft.com/en-us/library/cc221403(v=VS.95).aspx

Interacting between two threads

I am working on a winform application, and my goal is to make a label on my form visible to the user, and three seconds later make the label invisible. The issue here is timing out three seconds. I honestly do not know if this was the correct solution to my problem, but I was able to make this work by creating a new thread, and having the new thread Sleep for three seconds (System.Threading.Thread.Sleep(3000)).
I can't use System.Threading.Thread.Sleep(3000) because this freezes my GUI for 3 seconds!
private void someVoid()
{
lbl_authenticationProcess.Text = "Credentials have been verified authentic...";
Thread sleepThreadStart = new Thread(new ThreadStart(newThread_restProgram));
sleepThreadStart.Start();
// Once three seconds has passed / thread has finished: lbl_authenticationProcess.Visible = false;
}
private void newThread_restProgram()
{
System.Threading.Thread.Sleep(3000);
}
So, back to my original question. How can I determine (from my main thread) when the new thread has completed, meaning three seconds has passed?
I am open to new ideas as well as I'm sure there are many.

Right now, you are blocking the entire UI thread in order to hide a label after 3 seconds. If that's what you want, then just user Thread.Sleep(3000) from within the form. If not, though, then you're best off using a Timer:
System.Windows.Forms.Timer timer = new System.Windows.Forms.Timer();
timer.Interval = 3000;
timer.Tick += (s, e) => { this.lbl_authenticationProcess.Visible = false; timer.Stop(); }
timer.Start();
After 3 seconds, the label will disappear. While you're waiting for that, though, a user can still interact with your application.
Note that you must use the Forms version of Timer, since its Tick event is raised on the UI thread, allowing direct access to the control. Other timers can work, but interaction with the control would have to be Invoke/BeginInvoked.

Did you try to use Timer
System.Windows.Forms.Timer t = new System.Windows.Forms.Timer();
t.Interval = 3000;
t.Start();
t.Tick += new EventHandler(t_Tick);
void t_Tick(object sender, EventArgs e)
{
label.Visible = false;
}

You really don't need to synchronize anything. You just need a new thread, with a reference to your label. Your code is actually pretty close:
private void someVoid()
{
lbl_authenticationProcess.Text = "Credentials have been verified authentic...";
lbl_authenticationProcess.Visible = true;
Thread sleepThreadStart = new Thread(new ThreadStart(newThread_restProgram));
sleepThreadStart.Start();
}
private void newThread_restProgram()
{
System.Threading.Thread.Sleep(3000);
if (lbl_authenticationProcess.InvokeRequired) {
lbl_authenticationProcess.Invoke(new SimpleCallBack(makeInvisible));
} else {
makeInvisible();
}
}
private void makeInvisible()
{
lbl_authenticationProcess.Visible = false;
}
So, when someVoid() is called, the message on the label is set, the label is made visible. Then a new thread is started with the newThread_restProgram() as the body. The new thread will sleep for 3 seconds (allowing other parts of the program to run), then the sleep ends and the label is made invisible. The new thread ends automatically because it's body method returns.

You can make a method like so:
public void SetLbl(string txt)
{
Invoke((Action)(lbl_authenticationProcess.Text = txt));
}
And you would be able to call it from the second thread, but it invokes on the main thread.

If you're using .NET 3.5 or older, it's kinda a pain:
private void YourMethod()
{
someLabel.BeginInvoke(() =>
{
someLabel.Text = "Something Else";
Thread thread = new Thread(() =>
{
Thread.Sleep(3000);
someLabel.BeginInvoke(() => { someLabel.Visible = false; });
});
thread.Start();
});
}
That should stop you from blocking the UI.
If you're using .NET 4+:
Task.Factory.StartNew(() =>
{
someLabel.BeginInvoke(() => { someLabel.Text = "Something" });
}).ContinueWith(() =>
{
Thread.Sleep(3000);
someLabel.BeginInvoke(() => { someLabel.Visible = false; });
});

If you are willing to download the Async CTP then you could use this really elegant solution which requires the new async and await keywords.1
private void async YourButton_Click(object sender, EventArgs args)
{
// Do authentication stuff here.
lbl_authenticationProcess.Text = "Credentials have been verified authentic...";
await Task.Delay(3000); // TaskEx.Delay in CTP
lbl_authenticationProcess.Visible = false;
}
1Note that the Async CTP uses TaskEx instead of Task.

You can use an AutoResetEvent for your thread synchronization. You set the event to signalled when your secondary thread has woken from it's sleep, so that it can notify your main thread.
That means though that your main thread waits for the other thread to complete.
On that note, you can use SecondThread.Join() to wait for it to complete in your main thread.
You do either of the above, but you don't need to do both.
As suggested in the comments, having a UI thread sleep is not generally a good idea, as it causes unresponsiveness for the user.
However if you do that, you might as well just sleep your main thread and get rid of the extraneous need of the second thread.

I'm not exactly sure this is the right way to do it, but to answer your question, you have to use the Join() function.
public void CallingThread()
{
Thread t = new Thread(myWorkerThread);
t.Join();
}
public void WorkerThread()
{
//Do some stuff
}
You can also add a timeout as parameter to the function, but you don't need that here.

WPF Splash Screen Windows

I need to have a PNG (with transparency) as a splash screen. The transparent portions of the image should be clear so the user can see any windows behind it (or desktop).
I also need to display the splash screen for 5 seconds (the contract specifically says 5 seconds) and it can't be any shorter. I am aware of the build property in VS 2010 but the splash screen comes and goes too quick (less than 5 seconds).
What can I do to make it stay 5 seconds (approximately)

I had a similar problem, where i couldn't use the built-in splashscreen option, on a WPF project.
That project is now open source, you have have a look here: https://code.google.com/p/theomniscientchimp/
It's an auto-updater (there are a few things you don't need i guess).
This is the minimum you should need:
WPF side:
<Window x:Class="TheOmniscientChimp.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:CustomXaml"
Icon="SC2_Replay_Monkey.ico"
Title="MainWindow" Height="256" Width="456" Background="#00005555" AllowsTransparency="True" WindowStyle="None" WindowStartupLocation="CenterScreen" >
<Grid Width="Auto">
<Grid.RowDefinitions>
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Image Name="splashScreenImage" Stretch="Fill" Grid.Row="0" />
</Grid>
</Window>
C# side (code behind):
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
BitmapImage splashScreenImageSource = new BitmapImage();
splashScreenImageSource.BeginInit();
splashScreenImageSource.UriSource = new Uri("Your_Image.png", UriKind.Relative);
splashScreenImageSource.EndInit();
splashScreenImage.Source = splashScreenImageSource;
}
public void AsynchronousExit()
{
BackgroundWorker worker = new BackgroundWorker();
worker.DoWork += new DoWorkEventHandler(worker_DoWork);
worker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(worker_RunWorkerCompleted);
worker.RunWorkerAsync();
}
private void worker_DoWork(object sender, DoWorkEventArgs e)
{
//Makes the thread wait for 5s before exiting.
Thread.Sleep(5000);
}
private void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
Environment.Exit(0);
}
}
Tell me if you need help to adjust.
FB.

If i had to do it i would add a window and set its properties AllowsTransparency = true; set it to start before all forms i mean before loading this can be done by modifying App.xml and set Startup="Application_Startup
To disable the top defauld control you have to set WindowStyle = none
and there in its code
private void Application_Startup(object sender, StartupEventArgs e)
{
MainWindow mn = new MainWindow();
mn.ShowDialog();
}
use timer to do what ever you want
private DispatcherTimer timer;
timer = new DispatcherTimer();
timer.Tick += new EventHandler(timer_Tick);
timer.Interval = TimeSpan.FromMilliseconds(5000);
timer.IsEnabled = true;
void timer_Tick(object sender, EventArgs e)
{
///Close your window here
}
hope this helps

I had the same problem, buts it's actually suprisingly easy to solve without anything special:
add your image in to the main project and set the build property to Splash Screen.
add a Thread.Sleep(5000) into the constructor for your app's main window right before the InitializeComponents() call.
This will delay the loading of your main wpf window, and the splash screen will stay up for at least the load time + the time of the sleep before the main window pops up and the splash goes away.

You'll probably have to do something similar to what you'd do in WinForms. Spin up a new thread and start a Wpf Application on that thread. In WinForms you'd do this by using System.Windows.Forms.Application.Run(new SplashForm()); Should be something similar to this in Wpf.
EDIT:
I found this, so it should work. http://msdn.microsoft.com/en-us/library/ms597011.aspx
The key is to do this ON A SEPARATE THREAD. The thread the application starts is is already tied to one WPF application and you want your splash to basically be its own GUI. The form can then have a timer that causes it to close itself, which should automatically terminate this other application.

If you use want a splash screen window and use the background worker, you make your main code more complex as it is not necessary. The solution is to write the main code as a normal synchronous code style in main UI thread while showing the splash window until you close it, and you can send an update to change the splash screen loading text or progress bar.
SplashWindow window = null;
var thread = new Thread(new ThreadStart(() =>
{
Debug.Print("Thread begin");
window = new SplashWindow();
window.ShowDialog();
}));
thread.Name = "RunSplashWindow";
thread.SetApartmentState(ApartmentState.STA);
thread.IsBackground = true;
thread.Start();
Debug.Print("App begin");
Thread.Sleep(1000);
if (window != null)
{
window.Dispatcher.BeginInvoke(new Del(() => {
window.SetHeader("Running...");
}), new object[0]);
}
Thread.Sleep(1000);
for (int i = 1; i <= 100; i++)
{
if (window != null)
{
window.Dispatcher.BeginInvoke(new Del(() =>
{
window.SetProgress((double)i);
}), new object[0]);
}
Thread.Sleep(10);
}
Thread.Sleep(1000);
Debug.Print("App end");
if (window != null)
{
window.Dispatcher.BeginInvoke(new Del(() =>
{
window.Close();
}), new object[0]);
}