Solved

Is it OK to call my method from any thread?

Posted on 2011-09-16
4
340 Views
Last Modified: 2012-08-13
I get the part about not updating the UI unless you're on the main thread.

My question now is: on line 39 of the sample code below, is it OK to call my LogMsg() method even though I may be running on a different thread?

namespace xyzzy
{
  public partial class Form1 : Form
  {
    // delegate enables asynchronous calls from other threads
    delegate void AppendTextBox1Delegate(string text);

    public Form1()
    {
      InitializeComponent();
    }

    /* Call this method to append text to textBox1 */
    public void AppendTextBox1(string text)
    {
      if (this.textBox1.InvokeRequired)  // Check if we are running on a different thread
      {
        // It's on a different thread, so use Invoke. (We call ourself through a delegate.)
        AppendTextBox1Delegate d = new AppendTextBox1Delegate(AppendTextBox1);
        this.textBox1.Invoke (d, new object[] { text });
      }
      else
      {
        // It's on the main UI thread, no need for Invoke
        this.textBox1.AppendText(text + Environment.NewLine);
      }
    }


    private void LogMsg(string text)
    {
      AppendTextBox1(text);
    }


    private void serialPort1_ErrorReceived(object sender, SerialErrorReceivedEventArgs e)
    {
      //I could be on any thread. Can I still call LogMsg?
      LogMsg("serialPort1_ErrorReceived.");
    }

  }
}

Open in new window

0
Comment
Question by:deleyd
  • 2
4 Comments
 
LVL 36

Accepted Solution

by:
Miguel Oz earned 250 total points
ID: 36552950
Yes it is OK, as you are using Invoke if you are calling this.textBox1.Invoke from a different thread.
If you a solution with anonymous methods, check:
http://stackoverflow.com/questions/2367718/c-automating-the-invokerequired-code-pattern
0
 
LVL 36

Assisted Solution

by:Miguel Oz
Miguel Oz earned 250 total points
ID: 36552973
Forgot to add this link:
http://msdn.microsoft.com/en-us/library/ms171728(v=vs.80).aspx
(see SetText method)
0
 
LVL 85

Assisted Solution

by:Mike Tomlinson
Mike Tomlinson earned 125 total points
ID: 36553065
Agreed...it's safe.  But why not call AppendTextBox1() directly?...
0
 
LVL 13

Assisted Solution

by:Corey2
Corey2 earned 125 total points
ID: 36553133
You might want to consider BeginInvoke if there is any chance that the update could cause a subsequent log message (shouldn't in your sample), it will also allow the logging to happen without stopping the calling thread to wait for the logging to finish.

this.textBox1.BeginInvoke (d, new object[] { text });
0

Featured Post

How our DevOps Teams Maximize Uptime

Our Dev teams are like yours. They’re continually cranking out code for new features/bugs fixes, testing, deploying, responding to production monitoring events and more. It’s complex. So, we thought you’d like to see what’s working for us. Read the use case whitepaper.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Many of us here at EE write code. Many of us write exceptional code; just as many of us write exception-prone code. As we all should know, exceptions are a mechanism for handling errors which are typically out of our control. From database errors, t…
For those of you who don't follow the news, or just happen to live under rocks, Microsoft Research released a beta SDK (http://www.microsoft.com/en-us/download/details.aspx?id=27876) for the Xbox 360 Kinect. If you don't know what a Kinect is (http:…
Finds all prime numbers in a range requested and places them in a public primes() array. I've demostrated a template size of 30 (2 * 3 * 5) but larger templates can be built such 210  (2 * 3 * 5 * 7) or 2310  (2 * 3 * 5 * 7 * 11). The larger templa…
I've attached the XLSM Excel spreadsheet I used in the video and also text files containing the macros used below. https://filedb.experts-exchange.com/incoming/2017/03_w12/1151775/Permutations.txt https://filedb.experts-exchange.com/incoming/201…

713 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question