C#

public sealed class ExtendedBackgroundWorker : BackgroundWorker
{
  private Thread thread;
  public void Stop()
  {
    thread?.Abort(); // Abort the thread if it has been set.
	thread = null;
  }
  protected override void OnDoWork(DoWorkEventArgs eventArgs)
  {
    thread = Thread.CurrentThread;
	try
	{
	  base.OnDoWork(eventArgs);
	}
	catch (ThreadAbortException threadAbort)
	{
	  Debug.WriteLine("ExtendedBackgroundWorker has been aborted");
	  Thread.ResetAbort();
	  eventArgs.Cancel = true;
	}
  }
}

CloseCancelForm(); //This form contains the Cancel Button

public partial class FormCancelQuery : Form
    {
        DialogResult result = DialogResult.OK;
        public FormCancelQuery()
        {
            InitializeComponent();
        }

        private void btnCancel_Click(object sender, EventArgs e)
        {
            result = DialogResult.Cancel;
            this.Close();
        }
    }

private void qbTestQueryBtn_Click(object sender, EventArgs e)
        {            
            frmCancel = new FormCancelQuery();
            RunQueryThread = new Thread(new ThreadStart(RunQuery));
            RunQueryThread.Start();
            DialogResult dr = frmCancel.ShowDialog(this);
            if (dr == DialogResult.Cancel)
            {
                frmCancel.DialogResult = DialogResult.OK;
                RunQueryThread.Abort();
            }                       
        }

private void RunQuery()
        {
            if (ValidQuery())
            {
                string queryTestString = GlobalStr.previewQueryString;
                // Check the query for the where fill flag, and if it contains it, branch off to the filling routine
                string fillFlag = "'mandafillflag'";
                if (queryTestString.ToLower().Contains(fillFlag))
                {
                    MessageBox.Show("This query requires completing the fields. Click OK to begin procedure.");
                    QueryFiller qf = new QueryFiller();
                    queryTestString = qf.FillQuery(queryTestString.ToLower(), fillFlag);
                }

                GlobalStr.previewQueryString = queryTestString;
                //selectTB.Text = GlobalStr.previewQueryString;
                selectTB.Invoke(new MethodInvoker(delegate { selectTB.Text = GlobalStr.previewQueryString; }));
                //whereTB.Clear();
                whereTB.Invoke(new MethodInvoker(delegate { whereTB.Clear(); }));
                //fromTB.Clear();
                fromTB.Invoke(new MethodInvoker(delegate { fromTB.Clear(); }));
                //orderTB.Clear();
                orderTB.Invoke(new MethodInvoker(delegate { orderTB.Clear(); }));

                try
                {
                    //examineQueryInputString(GlobalStr.previewQueryString, "", cmplxWhereClauseCB.Checked);
                    examineQueryInputString(GlobalStr.previewQueryString, "", GlobalBool.g_CmplxWhereClauseChecked);
                }
                catch (System.Exception ex)
                {
                    CloseCancelForm();
                    MessageBox.Show(ex.Message);
                    return;
                }

                // Clear the data table
                
                try
                {
                    GlobalData.g_queryData.Rows.Clear();
                    GlobalData.g_queryData.Columns.Clear();
                }
                catch (Exception ex)
                {
                    GlobalData.g_queryData = new DataTable();                    
                }                
                
                // set the wait cursor if query takes long. ens 01/28/2015
                Cursor.Current = Cursors.WaitCursor;
                //using (SqlConnection connection = new SqlConnection(GlobalStr.sqlConnString))
                using (SqlConnection connection = new SqlConnection(GlobalStr.sqlConnStringMetadata))
                {
                    try
                    {
                        connection.Open();

                        /*
                         * DRW 3/10/2016
                         * Added the following Transaction object in order to set the isolation level of all queries
                         * run from MAnDA to to Read Uncommited.
                         */
                        SqlTransaction Transaction = connection.BeginTransaction(IsolationLevel.ReadUncommitted);

                        using (SqlCommand testQuery = new SqlCommand(GlobalStr.previewQueryString, connection))
                        {
                            /*
                             * DRW 3/11/2016
                             * User sets the query timeout value via a textbox on the main form. The value is held in a variable.
                             * testQuery.CommandTimeout = 300;
                             */

                            testQuery.CommandTimeout = m_QueryTimeout;
                            testQuery.Transaction = Transaction;                           

                            using (SqlDataAdapter adapter3 = new SqlDataAdapter(testQuery))
                            {
                                adapter3.Fill(GlobalData.g_queryData);

                                // Open the DataSetViewer form and send the table to it
                                DataSetViewer dsv = new DataSetViewer();
                                dsv.SetSource(GlobalData.g_queryData);
                                // set the dataview classification 05272015
                                string strClassification = string.Format("{0} {1}", GlobalStr.g_classification, GlobalStr.g_releaseability);
                                dsv.setClassification(strClassification);
                                Cursor.Current = Cursors.Default;
                                CloseCancelForm();
                                dsv.ShowDialog();

                                //dataGridView1.DataSource = GlobalData.g_queryData;
                            }
                        }
                        connection.Close();                        
                    }
                    catch (Exception ex)
                    {
                        //frmCancel.Invoke(new MethodInvoker(delegate { frmCancel.Close(); }));                        
                        if (ex.Message != "Thread was being aborted.")
                        {
                            CloseCancelForm();
                            /// Print error message
                            MessageBox.Show("The query test failed: " + ex.Message);                            
                        }
                        return;
                    }
                }
            }
            else
            {
                CloseCancelForm();
                MessageBox.Show("SQL test failed.");
            } 
        }

        private void CloseCancelForm()
        {            
            try
            {
                if (frmCancel.InvokeRequired)
                {
                    frmCancel.Invoke(new MethodInvoker(delegate { frmCancel.DialogResult = DialogResult.OK; }));
                    frmCancel.Invoke(new MethodInvoker(delegate { frmCancel.Close(); }));
                }
                else
                {
                    frmCancel.DialogResult = DialogResult.OK;
                    frmCancel.Close();
                }                
            }
            catch(Exception ex)
            {
                string message = ex.Message;
                return;
            }
        }

public class something
{
  public string Comments {get; private set;}
  public string Selos {get;set;}

  public void SetComments(string comment)
  {
    string[] wordsToFind = new string[] {"Selo:", "selo:", "Selos:", "selos:"};
    if(String.IsNullOrEmpty(comment) == true)
    {
      Selos = "None";
    }
    else
    {
      string[] result = comment.Split(wordsToFind, StringSplitOptions.RemoveEmptyEntries);
      Selos = resuls[0];
    }
  }
}