How do I invoke a UI method from a Systems.Timers thread in C#

Question

I have a windows form application. I am supposed a create an SQL job, and execute it. The SQL job consists of around 9 steps and takes around 4 hours to complete. I am supposed to display the status of the SQL job, in a datagridview, so that its not necessary to go to SQL server and monitor the events.

My code is as below

 public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {


            Thread t1 = new Thread(FirstThread);
            t1.Start();
            System.Timers.Timer timer = new System.Timers.Timer();
            timer.Interval = 500;
            timer.Enabled = true;

            timer.Elapsed += timer1_Tick;
            timer.Start();
            t1.Join();


        }
 private void FirstThread()
        {

            // Creates a job
            // Invoke the job, via a bat file

        }
 private void checkStatus()
        {            
            // Checks the status of the job using the EXEC sp_helpjob @jobName='JobName'
            // Populate the status on the DataGridView
            // If the status of the job, eg. 
            dataGridView1.DataSource = ds.Tables[0];
            int CurrentExecution = Convert.ToInt32(dt.Rows[0]["Current_Execution_Status"]);
            if (CurrentExecution == 4)
                label1.Text = "Job is Over";
        }

        private void timer1_Tick(object sender, EventArgs e)
        {

            checkStatus();
        }

I run into CrossThread Operation Not valid error. Could anyone please let me know how to call the UI controls inside the System.Timer Thread.

Patrick Hofman · Accepted Answer · 2015-03-24T15:48:32.607

3

You should call Invoke on the Control or Form:

this.Invoke((MethodInvoker)delegate() { label1.Text = "Job is Over"; });

Or BeginInvoke if you don't want to wait until the action ended:

this.BeginInvoke((MethodInvoker)delegate() { label1.Text = "Job is Over"; });

edited Mar 24 '15 at 15:48

answered Mar 24 '15 at 15:45

Patrick Hofman

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1

Or call [`BeginInvoke`](https://msdn.microsoft.com/en-us/library/system.windows.forms.control.begininvoke) ;-) – Uwe Keim Mar 24 '15 at 15:47
1

@UweKeim: Indeed. Updated. – Patrick Hofman Mar 24 '15 at 15:49
1

Or use `SynchronizationContext` or even better `async-await` ;) – Sriram Sakthivel Mar 24 '15 at 15:49
1

@SriramSakthivel: You are right. There are a lot of options. Sometimes too many :) – Patrick Hofman Mar 24 '15 at 15:50
But even the datagridview shows the Cross Thread operation error, how do I populate data inside it. – cmrhema Mar 24 '15 at 15:55
@cmrhema: Invoke it the same way. – Patrick Hofman Mar 24 '15 at 15:56
Should have updated long ago. Thank you. BeginInvoke works. – cmrhema Apr 01 '15 at 16:04

How do I invoke a UI method from a Systems.Timers thread in C#

1 Answers1