Suppose you have application (WinForm) in which you like to see the intermediate progress and status of a time taking process on the GUI of the Main Form. This Time taking process is running in a separate DLL. As the process progresses, the DLL sends current status/progress to Calling App (i.e. WinForm app).
In the GUI of the Calling app, progress and current status text of the process is displayed on Progress Bar as shown below:
Let us see how we can do this in a very simple way:
- Create a Main Application (WinForm app) as above with a “Start Process” button that is used for starting the process in my DLL. Add “StatusStrip” control too in the form. In StatusStrip, add ProgressBar (inbuilt) and StatusLable controls (inbuilt)
- Create a DLL (Class Library project) with a class named “MyClass”. Add the reference of this DLL into your Main Application.
- Now create a public delegate to raise the Status event to show the intermediate processing status on GUI in the Main Form as:
public delegate void MyDLL_InternalStatus(int progress, string statustext);
In this delegate, we are specifying the parameters:
progress variable is used for storing current percentage progress of the process.
Statustext variable is used for storing the current status message related to process.
- In “MyClass” class, Add a method TimeConsumingProcess() that simulates a process taking a lot of time. TimeConsumingProcess() is built up with smaller several tasks such as Task-1, task-2 etc. Assume each task takes some significant amount of time (to simulate the time consumption, I used Thread.Sleep() method)
Now we want to send current status to calling application. In order to do this, we call MyClassStatusEvent() after the ending of each task.
e.g. MyClassStatusEvent(10, "Task-1 is started. Task-1 is in process...");
- Now add a reference to your DLL into your Main Application project. Then create an object of the “MyClass” and subscribe its event as:
// MyClass object is created
oMyClass = new MyClassLibrary.MyClass();
// MyClass's event is subscribed here
oMyClass.MyClassStatusEvent +=
new MyClassLibrary.MyDLL_InternalStatus (oMyClass_MyClassStatusEvent);
This subscription will require an event handler, which we specify like this:
// Event Handler of MyClass's event
void oMyClass_MyClassStatusEvent(int progress, string statustext)
{
toolStripProgressBar.Value = progress; // Setting ProgreeBar Value
toolStripStatusLabel.Text = statustext; // Setting Status Text
// To refresh the GUI simultaneously as the background process progresses
Application.DoEvents();
}
So, the whole code of class “MyClass” looks like:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
namespace MyClassLibrary
{
// Created a public delegate in the same namespace but outside of the class "MyClass"
// in order to raise the Status event to show the intermediate processing status on
// GUI in the Main Form
public delegate void MyDLL_InternalStatus(int progress, string statustext);
public class MyClass
{
// Created a public event
public event MyDLL_InternalStatus MyClassStatusEvent;
public void TimeConsumingProcess()
{
// event firing
MyClassStatusEvent(10, "Task-1 is started. Task-1 is in process...");
Task1();
MyClassStatusEvent(20, "Task-1 is finished. Task-2 is in process...");
Task2();
MyClassStatusEvent(40, "Task-2 is finished. Task-3 is in process...");
Task3();
MyClassStatusEvent(60, "Task-3 is finished. Task-4 is in process...");
Task4();
MyClassStatusEvent(80, "Task-4 is finished. Task-5 is in process...");
Task5();
MyClassStatusEvent(100, "Task-5 is finished. All tasks completed sucessfully!");
}
// Suppose Task1 takes 2 seconds
private void Task1()
{
Thread.Sleep(1000);
}
// Suppose Task2 takes 2 seconds
private void Task2()
{
Thread.Sleep(2000);
}
// Suppose Task3 takes 4 seconds
private void Task3()
{
Thread.Sleep(4000);
}
// Suppose Task4 takes 3 seconds
private void Task4()
{
Thread.Sleep(3000);
}
// Suppose Task5 takes 2 seconds
private void Task5()
{
Thread.Sleep(2000);
}
}
}
And the code of the Calling application’s main form (“MyForm”) will look like:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace EventBubblerDemo
{
public partial class MyForm : Form
{
// Created an object of the Dll
MyClassLibrary.MyClass oMyClass;
public MyForm()
{
InitializeComponent();
// MyClass object is created
oMyClass = new MyClassLibrary.MyClass();
// MyClass's event is subscribed here
oMyClass.MyClassStatusEvent += new MyClassLibrary.MyDLL_InternalStatus(oMyClass_MyClassStatusEvent);
}
// Event Handler of MyClass's event
void oMyClass_MyClassStatusEvent(int progress, string statustext)
{
toolStripProgressBar.Value = progress; // Setting ProgreeBar Value
toolStripStatusLabel.Text = statustext; // Setting Status Text
// To refresh the GUI simultaneously as the background process progresses
Application.DoEvents();
}
/// <summary>
/// Start Button Click Method
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btn_Start_Click(object sender, EventArgs e)
{
oMyClass.TimeConsumingProcess();
}
}
}
