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

Question

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.

Answer 1

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);
        }
    }
}

Answer 2

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.

Answer 3

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.