In my previous article [BackgroundWorker Component Overview in Winforms - Part 1], I described the working of BackgroundWorker component in Winform Application. In this article, I will demonstrate how to use the BackgroundWorker component to run a time-consuming operation on a separate thread. Example fills the dataset in background thread and also shows progress-bar while method is running.
First I created a class which inherits from BackgroundWorker Class which contains following key elements:
- An Enum ActionType : which contains Enum of Actions to do in background. i.e. FillCustData, DownloadCustImgs, etc will be used in method OnDoWork
- A public variable DoWorkArgs of type Dictionary<String, Object> for passing Arguments in key, value pair to worker method.
- A public class ResultData which contains properties like ResultObject, MsgText, PassedArgs etc to pass information from worker thread to UI layer. So UI layer can know what happened during background and take action based on Result.
- A protected override void OnDoWork (DoWorkEventArgs e) method - a key method which is executed during in separate thread.
- A winform with Button to start process in background and progressbar component to show progress while method is executing in background.
Here is the code for custom APKWorker Class which inherits from BackgroundWorker Class:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.ComponentModel;
namespace TemplateApp
{
public class APKWorker : BackgroundWorker
{
private ActionType ActionName { get; set; }
private DataTable dtResult = null;
public Dictionary<String, Object> DoWorkArgs = new Dictionary<string, object>();
public APKWorker()
{
this.WorkerReportsProgress = true;
this.WorkerSupportsCancellation = false;
}
public APKWorker(ActionType ActionName) : this()
{
this.ActionName = ActionName;
}
protected override void OnDoWork(DoWorkEventArgs e)
{
switch (this.ActionName)
{
case ActionType.RegisterUser:
//Call to method RegisterUser()
break;
case ActionType.Insert_Usage_Statistic:
//Call to method Insert_Usage_Statistic()
break;
case ActionType.FillUsers:
int deptid = 0;
if (DoWorkArgs.Keys.Contains("deptid"))
deptid = (int)DoWorkArgs["deptid"];
dtResult = new DataTable();
dtResult.Columns.Add("UID", Type.GetType("System.Int32"));
dtResult.Columns.Add("UserName", Type.GetType("System.String"));
DataRow dr = null;
this.ReportProgress(30, "Started");
System.Threading.Thread.Sleep(2000);
for (int i = 0; i < 5; i++)
{
dr = dtResult.NewRow();
dr["UID"] = i;
dr["UserName"] = "Test" + i.ToString();
dtResult.Rows.Add(dr);
}
this.ReportProgress(80, "Data Filled");
System.Threading.Thread.Sleep(2000);
e.Result = new ResultData { PassedArgs = DoWorkArgs, MsgText = "Data Filled.", MsgType = ResultData.MessageType.Success, ResultObject = dtResult };
this.ReportProgress(100, "Completed");
break;
}
base.OnDoWork(e);
}
public enum ActionType
{
RegisterUser,
Insert_Usage_Statistic,
FillUsers
}
}
public class ResultData
{
public Object ResultObject { get; set; }
public string MsgText { get; set; }
public MessageType MsgType { get; set; }
public Dictionary<String, Object> PassedArgs { get; set; }
public enum MessageType
{
Success,
Failure
}
}
}
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.ComponentModel;
namespace TemplateApp
{
public class APKWorker : BackgroundWorker
{
private ActionType ActionName { get; set; }
private DataTable dtResult = null;
public Dictionary<String, Object> DoWorkArgs = new Dictionary<string, object>();
public APKWorker()
{
this.WorkerReportsProgress = true;
this.WorkerSupportsCancellation = false;
}
public APKWorker(ActionType ActionName) : this()
{
this.ActionName = ActionName;
}
protected override void OnDoWork(DoWorkEventArgs e)
{
switch (this.ActionName)
{
case ActionType.RegisterUser:
//Call to method RegisterUser()
break;
case ActionType.Insert_Usage_Statistic:
//Call to method Insert_Usage_Statistic()
break;
case ActionType.FillUsers:
int deptid = 0;
if (DoWorkArgs.Keys.Contains("deptid"))
deptid = (int)DoWorkArgs["deptid"];
dtResult = new DataTable();
dtResult.Columns.Add("UID", Type.GetType("System.Int32"));
dtResult.Columns.Add("UserName", Type.GetType("System.String"));
DataRow dr = null;
this.ReportProgress(30, "Started");
System.Threading.Thread.Sleep(2000);
for (int i = 0; i < 5; i++)
{
dr = dtResult.NewRow();
dr["UID"] = i;
dr["UserName"] = "Test" + i.ToString();
dtResult.Rows.Add(dr);
}
this.ReportProgress(80, "Data Filled");
System.Threading.Thread.Sleep(2000);
e.Result = new ResultData { PassedArgs = DoWorkArgs, MsgText = "Data Filled.", MsgType = ResultData.MessageType.Success, ResultObject = dtResult };
this.ReportProgress(100, "Completed");
break;
}
base.OnDoWork(e);
}
public enum ActionType
{
RegisterUser,
Insert_Usage_Statistic,
FillUsers
}
}
public class ResultData
{
public Object ResultObject { get; set; }
public string MsgText { get; set; }
public MessageType MsgType { get; set; }
public Dictionary<String, Object> PassedArgs { get; set; }
public enum MessageType
{
Success,
Failure
}
}
}
Code to write in Winform for Calling background worker class:
private void btnTest_Click(object sender, EventArgs e)
{
this.progressBar1.Minimum = 0;
this.progressBar1.Maximum = 100;
APKWorker objWorker = new APKWorker(APKWorker.ActionType.FillUsers);
objWorker.DoWorkArgs.Add("userid", 10);
objWorker.DoWorkArgs.Add("deptid", 3);
objWorker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(objWorker_RunWorkerCompleted);
objWorker.ProgressChanged += new ProgressChangedEventHandler(objWorker_ProgressChanged);
objWorker.RunWorkerAsync();
{
this.progressBar1.Minimum = 0;
this.progressBar1.Maximum = 100;
APKWorker objWorker = new APKWorker(APKWorker.ActionType.FillUsers);
objWorker.DoWorkArgs.Add("userid", 10);
objWorker.DoWorkArgs.Add("deptid", 3);
objWorker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(objWorker_RunWorkerCompleted);
objWorker.ProgressChanged += new ProgressChangedEventHandler(objWorker_ProgressChanged);
objWorker.RunWorkerAsync();
//Implementation Example 2:
//APKWorker objWorker = new APKWorker();
//objWorker.DoWork += new DoWorkEventHandler(objWorker_DoWork);
//objWorker.RunWorkerAsync();
//void objWorker_DoWork(object sender, DoWorkEventArgs e)
//{
// MessageBox.Show("hello");
//}
//Above example is useful, if you need to implement some custom logic in DoWork method. Here, first don't pass Actionname from Constructor,
//then add the 2nd line - objWorker.DoWork += new DoWorkEventHandler(objWorker_DoWork); and write custom logic in objWorker_DoWork
void objWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
this.progressBar1.Value = e.ProgressPercentage;
this.lblMsg.Text = (string)e.UserState;
}
void objWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
ResultData ResultObj = (ResultData)e.Result;
DataTable dtUser = (DataTable)ResultObj.ResultObject;
MessageBox.Show(ResultObj.PassedArgs["deptid"].ToString());
MessageBox.Show(dtUser.Rows[2]["UserName"].ToString());
MessageBox.Show("Done");
}
Hope this example will help to all who wants to use Background worker class to run long running methods in separate thread. Feel free to post your comments.
