How to update UI controls from another thread in ASP.NET?

Question

How to update UI controls(ex. list box) from another thread in ASP.NET? From the below code I am expecting to update listbox once performLongTask1() and performLongTask2() completes execution and also should update in the order of finishing task. protected void Button1_Click( object sender, EventArgs e) { Thread t1 = new Thread(performLongTask1); Thread t2 = new Thread(performLongTask2); t1.Start(); t2.Start(); ListBox1.Items.Add( "LongTask1 Started" ); ListBox1.Items.Add( "LongTask2 Started" ); } private void performLongTask1() { Thread.Sleep(5000); //ListBox1.Items.Add("LongTask1 Completed"); } private void performLongTask2() { Thread.Sleep(10000); //ListBox1.Items.Add("LongTask2 Completed"); }

Dinesh Gabhane · Answer

Try to use Label1.Refresh() after setting text and see if it works.

Dinesh Gabhane · Answer

This can not be done with Thread. You need to use Task for it. Use Async - Await with Task . you can easily perform your functinality

Pradeep S · Answer

@Dinesh I have tried with Async - Await with task as below, but "BtnClicked..." message is not shown up when the task is in execution and only when task is executed "Task execution completed" message is shown. protected async void Button1_Click( object sender, EventArgs e) { Task task = new Task(PerformWork); task.Start(); Label1.Text = "BtnClicked..." ; await task; Label1.Text = "Task execution completed" ; } private void PerformWork() { try { Thread.Sleep(2000); } catch (Exception ex) { Label1.Text = ex.Message; } } How to get "Btn Clicked..." message?