How to add/insert multi thread upon running or executing in WinForm (please see my code)

Question

When I run my codes and click the execute button, It hangs upon running(especially when I'm running more files) and i cannot click my main form anymore it needs to finish my execution first before interaction with my main form. I researched that i need to multi thread. How will i INSERT the code of the multi threading or backgroundworker so that i can still interact with my form.?

Here below is the execution button where when i click it start execution of my scipts and freezes my form when not finished.

    private void Execute_Click(object sender, EventArgs e)
    {

        try
        {                
            //Execution Pane
            timer1.Start();
            progressBar1.Maximum = checkedListBox1.CheckedItems.Count;

            richTextBox2.Text = "";
            string file_name = "\\test1.sql";
            file_name = textBox1.Text + file_name;
            {                 
                string line;
                line = null;

                foreach (Object item in checkedListBox1.CheckedItems)
                {

                    string sql_name = "\\test1.sql";
                    sql_name = textBox1.Text + sql_name;
                    StreamWriter SaveFile = new StreamWriter(sql_name);
                    SaveFile.WriteLine(":r \"" + textBox1.Text + "\\" + item + "\"");
                    SaveFile.Close();

                    line += item + "\n";

                    StreamReader sql = new StreamReader(sql_name);
                    //richTextBox1.Text = sr.ReadToEnd();
                    sql.Close();
                    sql.Dispose();

                    //Create a batchfile for execution of consolidated script 
                    string execute = "\\Script_Runner.bat";
                    execute = textBox1.Text + execute;
                    StreamWriter SaveFile2 = new StreamWriter(execute);
                    SaveFile2.WriteLine("sqlcmd -S localhost -E -i " + textBox1.Text + "\\" + "test1.sql");
                    //Environment.NewLine + "pause");
                    SaveFile2.Close();

                    //running the batchfile
                    string ScriptRun = "\\Script_Runner.bat";
                    ScriptRun = textBox1.Text + ScriptRun;
                    Process.Start(ScriptRun);

                    progressBar1.PerformStep();
                    this.Refresh();

                }

                richTextBox2.Text = line;
                richTextBox2.Text += "\nData Patch Completed.";

                transfer = label3.Text;
                NotificationForm NF = new NotificationForm();
                NF.Show();

            }

        }
        catch (Exception ex)
        {
            string filePath = @"C:\Error.txt";
            filePath = textBox1.Text + filePath;

            using (StreamWriter writer = new StreamWriter(filePath, false))
            {
                writer.WriteLine("Message :" + ex.Message + Environment.NewLine + "StackTrace :" + ex.StackTrace +
                   "" + Environment.NewLine + "Date :" + DateTime.Now.ToString());
                writer.WriteLine(Environment.NewLine + "-----------------------------------------------------------------------------" + Environment.NewLine);
            }
        }
    }                   

Answer 1

private void Execute_Click(object sender, EventArgs e)
{
  Task.Factory.StartNew(() =>
  {
    if (InvokeRequired)
    {
      Invoke(new MethodInvoker(DoSomething));
    }
    else
    {
      DoSomething();
    }
  });
}

private void DoSomething()
{
  try
  {
    //Execution Pane
    timer1.Start();
    progressBar1.Maximum = checkedListBox1.CheckedItems.Count;

    richTextBox2.Text = "";
    var file_name = "\\test1.sql";
    file_name = textBox1.Text + file_name;
    {
      string line;
      line = null;

      foreach (var item in checkedListBox1.CheckedItems)
      {
        var sql_name = "\\test1.sql";
        sql_name = textBox1.Text + sql_name;
        var SaveFile = new StreamWriter(sql_name);
        SaveFile.WriteLine(":r \"" + textBox1.Text + "\\" + item + "\"");
        SaveFile.Close();

        line += item + "\n";

        var sql = new StreamReader(sql_name);
        //richTextBox1.Text = sr.ReadToEnd();
        sql.Close();
        sql.Dispose();

        //Create a batchfile for execution of consolidated script 
        var execute = "\\Script_Runner.bat";
        execute = textBox1.Text + execute;
        var SaveFile2 = new StreamWriter(execute);
        SaveFile2.WriteLine("sqlcmd -S localhost -E -i " + textBox1.Text + "\\" + "test1.sql");
        //Environment.NewLine + "pause");
        SaveFile2.Close();

        //running the batchfile
        var ScriptRun = "\\Script_Runner.bat";
        ScriptRun = textBox1.Text + ScriptRun;
        Process.Start(ScriptRun);

        progressBar1.PerformStep();
        Refresh();
      }

      richTextBox2.Text = line;
      richTextBox2.Text += "\nData Patch Completed.";

      var transfer = label3.Text;
      //NotificationForm NF = new NotificationForm();
      //NF.Show();
    }
  }
  catch (Exception ex)
  {
    var filePath = @"C:\Error.txt";
    filePath = textBox1.Text + filePath;

    using (var writer = new StreamWriter(filePath, false))
    {
      writer.WriteLine("Message :" + ex.Message + Environment.NewLine + "StackTrace :" + ex.StackTrace +
                        "" + Environment.NewLine + "Date :" + DateTime.Now);
      writer.WriteLine(Environment.NewLine +
                        "-----------------------------------------------------------------------------" +
                        Environment.NewLine);
    }
  }
}