C#

When I pushed the Transfer button a second time, I get the this error message, System.InvalidOperationException: 'This BackgroundWorker is currently busy and cannot run multiple tasks concurrently.' Can someone help me with this problem?

private void buttonTransfer_Click(object sender, EventArgs e)
        {

                if (backgroundWorker1.IsBusy)
            {
                backgroundWorker1.WorkerSupportsCancellation = true;
                backgroundWorker1.CancelAsync();
                MessageBox.Show("Running!");
            }

                    richTextBoxViewStatus.Clear();
                    
            backgroundWorker1.WorkerReportsProgress = true;
            backgroundWorker1.RunWorkerAsync();

        }


private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            port.Close();
            backgroundWorker1.WorkerSupportsCancellation = true;
            backgroundWorker1.CancelAsync();
        }

      

        private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
        do some work
        }

Quote:

IDE: Integrated development environment
C#, Visual Studio 2019, Windows10Pro in
2.1

C#

Exception: An object reference does not point to an instance of an object.

Quote:

using System;
using System.IO;
using System.Text;
// - using System.Text.StringBuilder;
using System.Globalization;
using System.Windows.Forms;

using System.Threading;

// using Microsoft.CSharp;

namespace WFA_BankPercent
{
public partial class Form7 : Form
{
public Form7()
{
InitializeComponent();
}
//- string m_sWork44 = ""; // C# требует инициализации
private void Form7_Load(object sender, EventArgs e)
{

}

// below on forum www.codeproject.com 29032022
private void button21_Click(object sender, EventArgs e)
{
string line = System.String.Empty;
string s_sourse = System.String.Empty;
bool b_beforeRead = false;
bool b_afterRead = false;
string s_begin = "Begin";
string s_end = "End";
bool b_begin = false;
bool b_end = false;
int i_begin = 0;
int i_end = 0;
try
{
StreamReader sr = new StreamReader(@"D:\Input_my.txt");
StreamWriter sw = new StreamWriter("D:\\Out_my.txt", false, Encoding.UTF8);
line = sr.ReadLine();
byte k = 0; // temporary for debug

while (line != null)
{
// k++; // temporary
// //+if (k > 6) // read only the first 6 lines of the input file
////+ if (k > 17) // 15 lines were written to the output file, but there was no Exception
// if (k > 18) // 0 lines were written to the output file, Exception was
// goto Close_my;

if ((line.Trim().Length == 0))
goto label_read;

b_begin = line.Contains(s_begin);
b_end = line.Contains(s_end);

if (b_begin && b_end)
{
i_begin = line.IndexOf(s_begin);
i_end = line.IndexOf(s_end);
s_sourse = line.Substring(0, i_begin);
MessageBox.Show("in line found 'Begin' and 'End'\n" + line);
goto label_wr;
}
else
{
s_sourse = line;
goto label_wr;
}
goto label_read;

label_wr:
sw.WriteLine(s_sourse);
label_read:
b_beforeRead = line.Contains(s_begin);
line = sr.ReadLine();
b_afterRead = line.Contains(s_end);
} // end while (line != null)
Close_my:
line = sr.ReadLine();
MessageBox.Show("Does it get here?" + s_sourse);
sr.Close();
sw.Close();
} // end try
catch (Exception e1)
{
MessageBox.Show("2.1 Exception: " + e1.Message);
}
finally
{
MessageBox.Show("3.Executing finally block.");
}
} // end button21
}
}

int size = Convert.ToInt32(Console.ReadLine());

array[i] = Convert.ToInt32(Console.ReadLine());

Console.Write("Wrong input, only numbers");

//Ask how many array items need to be present
Console.Write("How many items in the array ");
int size = Convert.ToInt32(Console.ReadLine());
int[] array = new int[size];

//Enter array items
Console.WriteLine("Enter {0} array items", size);
for (int i = 0; i < size; i++)
{
    array[i] = Convert.ToInt32(Console.ReadLine());
}

// Print array items
Console.Write("\nThe following items are in the array: ");
for (int i = 0; i < size; i++)
{
    Console.Write("{0} ", array[i]);
}
Console.ReadLine();