4734c35111
git-svn-id: file:///srv/devel/repo-conversion/nuwi@9 d2e56fa2-650e-0410-a79f-9358c0239efd
255 lines
9.7 KiB
C#
255 lines
9.7 KiB
C#
using System;
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using System.Collections.Generic;
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using System.ComponentModel;
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using System.Data;
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using System.Drawing;
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using System.Text;
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using System.Windows.Forms;
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using System.Threading;
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using Nuclex.Support.Tracking;
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using Nuclex.Support.Scheduling;
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namespace Nuclex.Windows.Forms {
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/// <summary>
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/// Blocking progress dialog that prevents the user from accessing the application
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/// window during all-blocking background processes.
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/// </summary>
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public partial class ProgressReporterForm : Form {
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/// <summary>Initializes a new progress reporter</summary>
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internal ProgressReporterForm() {
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InitializeComponent();
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this.updateProgressDelegate = new MethodInvoker(updateProgress);
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this.asyncEndedDelegate = new EventHandler(asyncEnded);
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this.asyncProgressUpdatedDelegate = new EventHandler<ProgressUpdateEventArgs>(
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asyncProgressUpdated
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);
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}
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/// <summary>
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/// Shows the progress reporter until the specified progression has ended.
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/// </summary>
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/// <param name="progression">
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/// Progression for whose duration to show the progress reporter
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/// </param>
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public static void Track(Progression progression) {
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Track(null, progression);
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}
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/// <summary>
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/// Shows the progress reporter until the specified progression has ended.
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/// </summary>
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/// <param name="windowTitle">
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/// Text to be shown in the progress reporter's title bar
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/// </param>
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/// <param name="progression">
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/// Progression for whose duration to show the progress reporter
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/// </param>
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public static void Track(string windowTitle, Progression progression) {
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// Small optimization to avoid the lengthy control creation when
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// the progression has already ended
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if(progression.Ended)
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return;
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// Open the form and let it monitor the progression's state
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using(ProgressReporterForm theForm = new ProgressReporterForm()) {
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theForm.track(windowTitle, progression);
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}
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}
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/// <summary>Called when the user tries to close the form manually</summary>
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/// <param name="e">Contains flag that can be used to abort the close attempt</param>
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protected override void OnClosing(CancelEventArgs e) {
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base.OnClosing(e);
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// Only allow the form to close when the form is ready to close and the
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// progression being tracked has also finished.
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e.Cancel = (Thread.VolatileRead(ref this.state) < 2);
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}
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/// <summary>
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/// Shows the progress reporter until the specified progression has ended.
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/// </summary>
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/// <param name="windowTitle">
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/// Text to be shown in the progress reporter's title bar
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/// </param>
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/// <param name="progression">
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/// Progression for whose duration to show the progress reporter
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/// </param>
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private void track(string windowTitle, Progression progression) {
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// Set the window title if the user wants to use a custom one
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if(windowTitle != null)
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Text = windowTitle;
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// Only enable the cancel button if the progression can be aborted
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this.cancelButton.Enabled = (progression is IAbortable);
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// Subscribe the form to the progression it is supposed to monitor
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progression.AsyncEnded += this.asyncEndedDelegate;
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progression.AsyncProgressUpdated += this.asyncProgressUpdatedDelegate;
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// The progression might have ended before this line was reached, if that's
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// the case, we don't show the dialog at all.
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if(!progression.Ended)
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ShowDialog();
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// We're done, unsubscribe from the progression's events again
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progression.AsyncProgressUpdated -= this.asyncProgressUpdatedDelegate;
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progression.AsyncEnded -= this.asyncEndedDelegate;
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}
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/// <summary>Called when the progression has ended</summary>
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/// <param name="sender">Progression that has ended</param>
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/// <param name="arguments">Not used</param>
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private void asyncEnded(object sender, EventArgs arguments) {
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// If the new state is 2, the form was ready to close (since the state
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// is incremented once when the form becomes ready to be closed)
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int newState = Interlocked.Increment(ref this.state);
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if(newState == 2) {
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// Close the dialog. Ensure the Close() method is invoked from the
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// same thread the dialog was created in.
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if(InvokeRequired)
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Invoke(new MethodInvoker(Close));
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else
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Close();
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}
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}
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/// <summary>Called when the tracked progression's progress updates</summary>
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/// <param name="sender">Progression whose progress has been updated</param>
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/// <param name="arguments">
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/// Contains the new progress achieved by the progression
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/// </param>
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private void asyncProgressUpdated(object sender, ProgressUpdateEventArgs arguments) {
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// Set the new progress without any synchronization
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this.currentProgress = arguments.Progress;
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// Another use of the double-checked locking idiom, here we're trying to optimize
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// away the lock in case some "trigger-happy" progressions send way more
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// progress updates than the poor control can process :)
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if(!this.progressUpdatePending) {
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lock(this) {
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if(!this.progressUpdatePending) {
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this.progressUpdatePending = true;
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this.progressUpdateAsyncResult = BeginInvoke(this.updateProgressDelegate);
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}
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} // lock
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}
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}
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/// <summary>Synchronously updates the value visualized in the progress bar</summary>
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private void updateProgress() {
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lock(this) {
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// Reset the update flag so incoming updates will cause the control to
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// update itself another time.
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this.progressUpdatePending = false;
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EndInvoke(this.progressUpdateAsyncResult);
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// Until the first progress event is received, the progress reporter shows
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// a marquee bar to entertain the user even when no progress reports are
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// being made at all.
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if(this.progressBar.Style == ProgressBarStyle.Marquee)
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this.progressBar.Style = ProgressBarStyle.Blocks;
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// Transform the progress into an integer in the range of the progress bar's
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// min and max values (these should normally be set to 0 and 100).
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int min = this.progressBar.Minimum;
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int max = this.progressBar.Maximum;
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int progress = (int)(this.currentProgress * (max - min)) + min;
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// Update the control
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this.progressBar.Value = Math.Min(Math.Max(progress, min), max);
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// Assigning the value sends PBM_SETPOS to the control which,
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// according to MSDN, already causes a redraw!
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//base.Invalidate();
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} // lock
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}
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/// <summary>
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/// One-time timer callback that ensurs the form doesn't stay open when the
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/// close request arrives at an inappropriate time.
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/// </summary>
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/// <param name="sender">Timer that has ticked</param>
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/// <param name="e">Not used</param>
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private void controlCreationTimerTicked(object sender, EventArgs e) {
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// This timer is intended to run only once to find out when the dialog has
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// been fully constructed and is running its message pump. So we'll disable
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// it as soon as it has been triggered once.
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this.controlCreationTimer.Enabled = false;
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// If the new state is 2, then the form was requested to close before it had
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// been fully constructed, so we should close it now!
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int newState = System.Threading.Interlocked.Increment(ref this.state);
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if(newState == 2)
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Close();
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}
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/// <summary>
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/// Aborts the background operation when the user clicks the cancel button
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/// </summary>
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/// <param name="sender">Button that has been clicked</param>
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/// <param name="e">Not used</param>
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private void cancelClicked(object sender, EventArgs e) {
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if(this.abortReceiver != null) {
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// Do this first because the abort receiver might trigger the AsyncEnded
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// event in the calling thread and thus destroy our window even in
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// the safe and synchronous UI thread :)
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this.cancelButton.Enabled = false;
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// Now we're ready to abort!
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this.abortReceiver.AsyncAbort();
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this.abortReceiver = null;
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}
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}
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/// <summary>Delegate for the asyncEnded() method</summary>
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private EventHandler asyncEndedDelegate;
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/// <summary>Delegate for the asyncProgressUpdated() method</summary>
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private EventHandler<ProgressUpdateEventArgs> asyncProgressUpdatedDelegate;
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/// <summary>Delegate for the progress update method</summary>
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private MethodInvoker updateProgressDelegate;
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/// <summary>Whether an update of the control state is pending</summary>
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private volatile bool progressUpdatePending;
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/// <summary>Async result for the invoked control state update method</summary>
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private volatile IAsyncResult progressUpdateAsyncResult;
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/// <summary>Most recently reported progress of the tracker</summary>
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private volatile float currentProgress;
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/// <summary>Whether the form can be closed and should be closed</summary>
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/// <remarks>
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/// 0: Nothing happened yet
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/// 1: Ready to close or close requested
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/// 2: Ready to close and close requested, triggers close
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/// </remarks>
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private int state;
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/// <summary>
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/// If set, reference to an object implementing IAbortable by which the
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/// ongoing background process can be aborted.
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/// </summary>
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private IAbortable abortReceiver;
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}
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} // namespace Nuclex.Windows.Forms
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