I have a Background Task that uploads a file, and i want it to report the progress to a progressbar on another form. How would i go about that? I'm slightly new to C# but long time VB .net programmer.
I was messing with this code but its totally wrong.
System.Windows.Forms.Form progForm = new ProgressWindows();
Control[] ctrls = progForm.Controls.Find("fileProgress1", true);
If you're using a BackgroundWorker then just call ReportProgress. Otherwise you'll need to dispatch the UI change to the correct thread. In WinForms see the Control.InvokeRequired property and related methods. The WPF equivalent is DispatcherObject.VerifyAccess.
Edit: Visual Studio isn't in front of me so there may be some minor compile errors.
public partial class MyForm : Form
{
public MyForm()
{
InitializeComponent(); // fileProgress1 setup.
}
private void StartTask()
{
Task t1 = new Task(BackgroundMethod1, fileProgress1); // Explicitly pass a reference to the progress bar.
Task t2 = new Task(BackgroundMethod2); // Use a method that has access to the bar.
Task t5 = new Task(BackgroundMethod3, IncrementPBMethod); // Pass an action to the background method. Abstracting the physical progress bar as something where you can set the progress.
Task t4 = new Task(delegate() { /* fileProgress1 referened*/ }); // Create a closure. I don't recommend this method.
}
private static void BackgroundMethod1(ProgressBar pb)
{
for(int i = 0; i < 100; ++i)
{
if(pb.InvokeRequired)
{
pb.Invoke(delegate() { pb.Value = i; });
}
Thread.Sleep(1000);
}
}
private void BackgroundMethod2()
{
for(int i = 0; i < 100; ++i)
{
if(fileProgress1.InvokeRequired)
{
fileProgress1.Invoke(delegate() { fileProgress1.Value = i; });
}
Thread.Sleep(1000);
}
}
private static BackgroundMethod3(Action<int> setProgress)
{
for(int i = 0; i < 100; ++i)
{
setProgress(i);
Thread.Sleep(1000);
}
}
private void IncrementPBMethod(int value)
{
if(fileProgress1.InvokeRequired)
{
fileProgress1.Invoke(IncrementPBMethod, value);
}
else
{
fileProgress1.Value = value;
}
}
}
If you problem is just accessing the fileProgress1. The easiest solution is make it public in the ProgressWindow class. By default controls are private.
Then you can access the fileProgress1 control as below.
ProgressWindows progForm = new ProgressWindows();
//progForm.fileProgress1
However the better way is exposing a public method in the PrefressWindows class that updates the progress.
In the ProgressWindows Class
public void UpdateProgressBar(int percentage)
{
// Set the progress in the progress bar.
fileProgress1.Percentage = percentage;
}
Call the above method as below.
ProgressWindows progForm = new ProgressWindows();
progForm.UpdateProgressBar(percentage);
I'm assuming that your second form (the one you want to show progress in) is instantiated in the form doing the "task". Why don't you simply create a public method in the second form that excepts an integer parameter to update the progress bar value? Seems like a relatively easy solution.
Related
I'm trying to make a progress bar for my project but while the work is being done they shouldn't be able to interact with the main window (this is why it needs to be ShowDialog). So I've came with this solution but due to having zero multi-threading experience I don't know if this is good solution.
This is just some model code to represent the work that needs to be done and works like it's meant to.
private async void Button_Click(object sender, RoutedEventArgs e)
{
Window1 progress_Bar = new Window1();
Thread test = new Thread(() => test_method(progress_Bar));
test.Start();
for (int i = 0; i < 11; i++)
{
//work
progress_Bar.Bar.Value = i;
await Task.Delay(1000);
}
progress_Bar.Close();
test.Abort();
}
private void test_method(Window1 _Test)
{
_Test.Dispatcher.Invoke(() =>
{
_Test.ShowDialog();
});
}
Where: Window1 is the progress bar window form I'm opening and the user sees while the work is being done and .Bar is the progress bar.
So my main question, is this using threads in a secure a proper way to do asynchronous tasking?
I'd look into the IProgress T interface.
Create a class that will hold your progress information like progress value, max, min if needed..
public class MyProgressReport
{
public int ProgressValue{ get; set; }
}
And a ReportProgress method somewhere in your class which will take progress reports and update info on the UI
private void ReportProgress(MyProgressReport progressReport)
{
//your dialog window needs a property to handle progress
//or just access its Bar.Value like you do in your example
dialogWindow.Progress = progressReport.ProgressValue;
}
And finally a method for showing the dialog / doing work. Tell it what you want to do with an Action.
public async void ShowBusyWindow(Action<IProgress<MyProgressReport>> operation)
{
//ReportProgress method will be called every time you want to update progress
var progressCallback = new Progress<MyProgressReport>(ReportProgress);
progressWindow = new Window();
var workTask = DoWork(operation(progressCallback));
progressWindow.ShowDialog(); //program will wait here until window is closed
await workTask; // usually not needed since workTask will be done by the time this is hit, this is where exceptions will be thrown
}
private async Task DoWork(Action operation)
{
//you should also check for exceptions here and close window
await Task.Run(operation);
//close window when done
progressWindow.Close();
}
Finally, to use it, you would just call Show like so:
ShowBusyWindow((progress) =>
{
//do work here and update progress
var report = new MyProgressReport();
for(int i=0; i<100; i++)
{
report.ProgressValue = i;
progress.Report(report);
Thread.Sleep(500);
}
});
I haven't run this (mistakes may be present) but I use an almost identical approach with some more properties on the progress report class and exception handling.
You need an async ShowDialog method for that
public static class WindowExtensions
{
public static async Task<bool?> ShowDialogAsync(this Window window)
{
await Task.Yield(); // this is the magic ;o)
return window.ShowDialog();
}
}
and now you can do
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
private async void Button_Click( object sender, RoutedEventArgs e )
{
var dialog = new WaitWindow();
var task = WorkAsync( dialog.Progress );
var dialogTask = dialog.ShowDialogAsync();
await task;
dialog.Close();
await dialogTask;
}
private async Task WorkAsync( IProgress<double> progress )
{
for ( int i = 0; i < 100; i++ )
{
progress.Report( i );
await Task.Delay( 25 ).ConfigureAwait( false );
}
}
}
the WaitWindow class
public partial class WaitWindow : Window
{
public WaitWindow()
{
InitializeComponent();
Progress = new Progress<double>( progress => ProgressHandler( progress ) );
}
public IProgress<double> Progress { get; }
private void ProgressHandler( double progress )
{
progressBar.Value = progress;
}
}
I've been playing around with multithreading and reading up on some of the questions here, but I haven't found an answer that directly addresses my concerns here.
I have an application that runs on a single thread, except for a progress bar in a separate window. Based on my research, I need to create a new thread for that form which will redraw the form's controls as it's properties change. I've reduced the problem to a simple example below:
Here's the 'main' program:
class Program
{
static MyForm form;
static void Main(string[] args)
{
form = new MyForm();
form.Show();
doWork();
form.Close();
}
//arbitrary example of processing that takes some period of time
static void doWork()
{
while (form.Value < 100000)
{
form.ChangeVal();
Thread.Sleep(1);
}
return;
}
}
...And here's the Form. I'm not including the auto-generated stuff from VS.
public partial class MyForm : Form
{
private int val;
public int Value
{
get { return val; }
set { val = value; }
}
public Thread GUIupdater;
public MyForm()
{
InitializeComponent();
this.Refresh();
}
private void MyForm_Load(object sender, EventArgs e)
{
GUIupdater = new Thread(new ThreadStart(GUIupdaterThread));
GUIupdater.Start();
this.FormClosing += new System.Windows.Forms.FormClosingEventHandler(killThreadOnClose);
}
public void ChangeVal()
{
val++;
}
private void changeLabel(string s)
{
label.Text = s;
label.Refresh();
}
private delegate void labelChanger(string s);
private void GUIupdaterThread()
{
while (true)
{
Invoke(new labelChanger(changeLabel), new object[]{val.ToString()} );
Thread.Sleep(100); //100 ms
}
}
private void killThreadOnClose(object sender, FormClosingEventArgs e)
{
GUIupdater.Abort();
}
}
So, my intention here is to have the calculations running constantly, with the window's graphics updating reasonably quickly. When I run the program, however, the invoke function is only called once, and the label never actually updates!
Any and all feedback is appreciated. If you want to view the code in an IDE you can download my project from Here
Edits:
When I add Console.WriteLine Statements, I discovered that the GUIupdaterThread (the thing that's meant to update the GUI) loop always 'breaks' on the Invoke statement, never reaching 'Thread.Sleep'. I changed it to 'BeginInvoke', which causes the loop to function properly, but this hasn't changed the fact that the GUI doesn't update.
CLARIFICATIONS:
About my 'actual' project:
The main thread here in 'Program' simulates my software, which is a plugin implementing an interface. My decision to alter val / value in that thread, not in the thread created by the window, was deliberate.
I'm constrained to using .NET 4.0 . any more recent features can't help me
Since in your application you have GUI thread (main thread) - all UI controls will be accessible from this thread only.
There are several approaches how to update controls from other threads.
I would like to recommend you to use one of modern and native approaches based on Progress < T > class (it's native for .Net platform).
I would suggest overriding the form's OnPaint method. Then inside ChangeVal, after you have updated whatever variables/data you need to update, call this.Invalidate which should trigger the form to repaint itself.
Or if you're just updating a single label, call label.Refresh in your ChangeVal method. The form should update correctly. Here's an example that worked for me:
This form has a single label on it.
public partial class ProgressForm : Form
{
private int currentValue = 0;
public ProgressForm()
{
InitializeComponent();
}
public void ChangeValue(int newValue)
{
currentValue = newValue;
lblValue.Text = string.Format("Current value: {0}", currentValue);
lblValue.Refresh(); //Call Refresh to make the label update itself
}
}
static class Program
{
private static ProgressForm progressForm = null;
[STAThread]
static void Main()
{
//Application.EnableVisualStyles();
//Application.SetCompatibleTextRenderingDefault(false);
//Application.Run(new Form1());
progressForm = new ProgressForm();
progressForm.Show();
doWork();
progressForm.Close();
}
//arbitrary example of processing that takes some period of time
static void doWork()
{
int i = 0;
while (i < 100000)
{
progressForm.ChangeValue(i);
Thread.Sleep(1);
i++;
}
return;
}
}
You may use the following instead as you are trying to access UI control other than main thread (from which it is created).
while ( true )
{
Invoke ( ( Action ) (() =>
{
label.Text = val.ToString();
label.Refresh()
Application.DoEvents();
}));
Thread.Sleep( 100 );
}
I recommend you to use "backgroundworker".
First add CheckForIllegalCrossThreadCalls = false; to initialization part otherwise InvalidOperationException occurs.
private void btnDoIt_Click(object sender, EventArgs e)
{
backgroundWorker.RunWorkerAsync();
}
private void backgroundWorker_DoWork(object sender, DoWorkEventArgs e)
{
Foo();
}
int total = 0;
private void Foo()
{
for (int i = 0; i <= 100000; i++)
{
total += i;
this.Text = i.ToString();
}
}
private void backgroundWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
// Run next process
}
Working on a C# project which I would like to implement a "waiting" (throbber) indicator in a separate form. After much research and trial and error it appears as the suggested method of doing this is to load a form using a separate thread from the one from the current form/thread.
The reason I went with this method was because initially using the Show() method on the throbber form produced a transparent form. I cannot use ShowDialog because I need to run some code after the throbber is displayed, after which that completes I would like to close the throbber form.
Anyway .. after trying many different methods to load the throbber form in a separate thread I still get an error about trying to access it from a thread which is different from the one it was created in. Here is a skelton version of the project code that should shed some light on my issue:
the example I was working off of for multithreading was this popular link for creating your own spashscreen in a separate thread ... http://www.codeproject.com/Articles/5454/A-Pretty-Good-Splash-Screen-in-C
public class Main
{
public void CheckData()
{
try
{
ProgressBar pb = new ProgressBar();
pb.ShowProgressBar();
//do data checking here
pb.CloseForm()
}
catch(Exception e)
{
}
}
}
public partial class ProgressBar : Form
{
static Thread ms_oThread = null;
public bool shouldStop = false;
static ProgressBar ms_ProgBar = null;
public ProgressBar()
{
InitializeComponent();
//DoWork();
}
public void ShowForm()
{
ms_ProgBar = new ProgressBar();
Application.Run(ms_ProgBar);
}
public void CloseForm()
{
ms_ProgBar.Close();
}
public void ShowProgressBar()
{
// Make sure it is only launched once.
if (ms_ProgBar != null)
return;
ms_oThread = new Thread(new ThreadStart(ShowForm));
ms_oThread.IsBackground = true;
ms_oThread.SetApartmentState(ApartmentState.STA);
ms_oThread.Start();
while (ms_ProgBar == null || ms_ProgBar.IsHandleCreated == false)
{
System.Threading.Thread.Sleep(1000);
}
}
}
You are creating your ProgressBar twice. Once in your main function, and once in your new thread. You are also calling your CloseWindow method from your main function (and on the window that is never shown), rather than on your new thread window.
You only want to create ProgressBar and show it using your new thread. Make your static ProgressBar field public so you can call close on it directly from Main, but make sure to use Invoke to do it since it's not on that Window's GUI thread.
Also, ShowProgressBar should be static.
Here's a rewrite attempt:
public class Main
{
public void CheckData()
{
try
{
ProgressBar.ShowProgressBar();
//do data checking here
ProgressBar.CloseForm();
}
catch(Exception e)
{
}
}
}
public partial class ProgressBar : Form
{
static ProgressBar _progressBarInstance;
public ProgressBar()
{
InitializeComponent();
//DoWork();
}
static void ShowForm()
{
_progressBarInstance = new ProgressBar();
Application.Run(ms_ProgressBar);
}
public static void CloseForm()
{
_progressBarInstance.Invoke(new Action(_progressBarInstance.Close));
_progressBarInstance= null;
}
public static void ShowProgressBar()
{
// Make sure it is only launched once.
if (_progressBarInstance != null)
return;
var ms_oThread = new Thread(new ThreadStart(ShowForm));
ms_oThread.IsBackground = true;
ms_oThread.SetApartmentState(ApartmentState.STA);
ms_oThread.Start();
}
}
I've gotten this type of thing working in the past with a BackgroundWorker, but I want to use the new async/await approach of .NET 4.5. I may be barking up the wrong tree. Please advise.
Goal: Create a component that will do some long-running work and show a modal form with a progress bar as it's doing the work. The component will get the handle to a window to block interaction while it's executing the long-running work.
Status: See the code below. I thought I was doing well until I tried interacting with the windows. If I leave things alone (i.e. don't touch!), everything runs "perfectly", but if I do so much as click on either window the program hangs after the long-running work ends. Actual interactions (dragging) are ignored as though the UI thread is blocked.
Questions: Can my code be fixed fairly easily? If so, how? Or, should I be using a different approach (e.g. BackgroundWorker)?
Code (Form1 is a standard form with a ProgressBar and a public method, UpdateProgress, that sets the ProgressBar's Value):
using System;
using System.Diagnostics;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Starting..");
var mgr = new Manager();
mgr.GoAsync();
Console.WriteLine("..Ended");
Console.ReadKey();
}
}
class Manager
{
private static Form1 _progressForm;
public async void GoAsync()
{
var owner = new Win32Window(Process.GetCurrentProcess().MainWindowHandle);
_progressForm = new Form1();
_progressForm.Show(owner);
await Go();
_progressForm.Hide();
}
private async Task<bool> Go()
{
var job = new LongJob();
job.OnProgress += job_OnProgress;
job.Spin();
return true;
}
void job_OnProgress(int percent)
{
_progressForm.UpdateProgress(percent);
}
}
class LongJob
{
public event Progressed OnProgress;
public delegate void Progressed(int percent);
public void Spin()
{
for (var i = 1; i <= 100; i++)
{
Thread.Sleep(25);
if (OnProgress != null)
{
OnProgress(i);
}
}
}
}
class Win32Window : IWin32Window
{
private readonly IntPtr _hwnd;
public Win32Window(IntPtr handle)
{
_hwnd = handle;
}
public IntPtr Handle
{
get
{
return _hwnd;
}
}
}
}
The async and await keywords do not mean "run on a background thread." I have an async/await intro on my blog that describes what they do mean. You must explicitly place CPU-bound operations on a background thread, e.g., Task.Run.
Also, the Task-based Asynchronous Pattern documentation describes the common approaches with async code, e.g., progress reporting.
class Manager
{
private static Form1 _progressForm;
public async Task GoAsync()
{
var owner = new Win32Window(Process.GetCurrentProcess().MainWindowHandle);
_progressForm = new Form1();
_progressForm.Show(owner);
var progress = new Progress<int>(value => _progressForm.UpdateProgress(value));
await Go(progress);
_progressForm.Hide();
}
private Task<bool> Go(IProgress<int> progress)
{
return Task.Run(() =>
{
var job = new LongJob();
job.Spin(progress);
return true;
});
}
}
class LongJob
{
public void Spin(IProgress<int> progress)
{
for (var i = 1; i <= 100; i++)
{
Thread.Sleep(25);
if (progress != null)
{
progress.Report(i);
}
}
}
}
Note that the Progress<T> type properly handles thread marshaling, so there's no need for marshaling within Form1.UpdateProgress.
#StephenCleary's answer is correct. Though, I had to make a little modification to his answer to get the behavior what I think OP wants.
public void GoAsync() //no longer async as it blocks on Appication.Run
{
var owner = new Win32Window(Process.GetCurrentProcess().MainWindowHandle);
_progressForm = new Form1();
var progress = new Progress<int>(value => _progressForm.UpdateProgress(value));
_progressForm.Activated += async (sender, args) =>
{
await Go(progress);
_progressForm.Close();
};
Application.Run(_progressForm);
}
private async void button1_Click(object sender, EventArgs e)
{
IProgress<int> progress = new Progress<int>(value => { progressBar1.Value = value; });
await Task.Run(() =>
{
for (int i = 0; i <= 100; i++)
progress.Report(i);
});
}
Correct me if I'm wrong, but this seems to be the easiest way to update a progress bar.
I have a FTP proccess that run without UI. and have a winform that use this ftp control. in that window I have a progressbar that show the ftp upload progress. The progress arrives to the window via interfase that is updated on the underliying presenter (I'm using MVP pattern).
My problem is when try to update the progress, it allways throw me this exception.
Through threads illegal operation: control 'prgProgresoSubido' is accessed from a thread other than that in which you created it.
That problem persists even if I use a BackGroundWorker in the Form.
// This is a delegated on presenter when a File finish to upload
void client_FileUploadCompletedHandler(object sender, FileUploadCompletedEventArgs e)
{
string log = string.Format("{0} Upload from {1} to {2} is completed. Length: {3}. ",
DateTime.Now, e.LocalFile.FullName, e.ServerPath, e.LocalFile.Length);
archivosSubidos += 1;
_Publicacion.ProgresoSubida = (int)((archivosSubidos / archivosXSubir) * 100);
//this.lstLog.Items.Add(log);
//this.lstLog.SelectedIndex = this.lstLog.Items.Count - 1;
}
// This is My interfase
public interface IPublicacion
{
...
int ProgresoSubida { set; }
}
/// And Here is the implementartion of the interfase on the form
public partial class PublicarForm : Form ,IPublicacion
{
//Credenciales para conectarse al servicio FTP
public FTPClientManager client = null;
public XmlDocument conf = new XmlDocument();
public string workingDir = null;
public webTalk wt = new webTalk();
private readonly PublicacionesWebBL _Publicador;
public PublicarForm()
{
InitializeComponent();
String[] laPath = { System.AppDomain.CurrentDomain.BaseDirectory};
String lcPath = System.IO.Path.Combine(laPath);
_Publicador = new PublicacionesWebBL(this, lcPath);
}
public int ProgresoSubida
{
set
{
// This is my prograss bar, here it throw the exception.
prgProgresoSubido.Value = value;
}
}
}
How can I do to avoid this problem ?
In general, all updates to the User Interface and Controls has to be done from the main thread (event dispatcher). If you attempt to modify the properties of a control from a different thread you will get an exception.
You must call Control.Invoke to invoke on the event dispatcher the method that updates your UI
Control.Invoke
Here, place a button and a label on a form, then try this
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
Thread t = new Thread(new ThreadStart(TestThread));
t.Start();
}
private void TestThread()
{
for (int i = 0; i < 10; i++)
{
UpdateCounter(i);
Thread.Sleep(1000);
}
}
private void UpdateCounter(int i)
{
if (label1.InvokeRequired)
{
label1.Invoke(new ThreadStart(delegate { UpdateCounter(i); }));
}
else
{
label1.Text = i.ToString();
}
}
}
Realize, that if you are firing an event from a thread, that the event will be on the same Thread. Therefore, if that thread is not the event dispatcher, you'll need to invoke.
Also, there may be mechanisms that BackgroundWorker gives you (As the commentator said) that simplify this for you, but I've never used it before so I'll leave that up to you to investigate.
As Alan has just pointed out, you must do all operations with UI controls in UI thread.
Just modify your property like this:
public int ProgresoSubida
{
set
{
MethodInvoker invoker = delegate
{
prgProgresoSubido.Value = value;
}
if (this.InvokeRequired)
{
Invoke(invoker);
}
else
{
invoker();
}
}
}