C# - 从线程更新窗口表单元素

Question

我目前正在创建一个程序来将笔记本电脑备份到USB记忆棒。我创建了一个调用方法的类。然后，我通过单独的线程开始实际备份。目前，我正在尝试通过此线程更改文本框和进度条。但是，它始终仅立即显示第一个更改，而仅在程序运行时才显示另一个进度。我已经尝试了互联网上的几种解决方案，但到目前为止没有任何效果。也许有人在这里有一个解决方案。

    backup sales_backup = new backup();
    //Start Backup Button
    private void backup_button_Click(object sender, EventArgs e)
    {
        Thread backupprocess = new Thread(new 
        ThreadStart(sales_backup.backup_start));
        backupprocess.Start();
    }
    //Backup Function
        public void backup_start()
        {
            files_to_copy = 0;
            files_copied = 0;
            var principalForm = System.Windows.Forms.Application.OpenForms.OfType<Form1>().FirstOrDefault();
            if (principalForm.drive_selector.SelectedItem != null)
            {
                //Set Parameters
                principalForm.backup_button.Visible = false;
                error_copy = false;
                error_message = "";
                device_removed = false;
                //Fill variables
                string temp = principalForm.drive_selector.SelectedItem.ToString();
                temp = regex_matching_return_match(temp, @"[A-Z,a-z](:\)");
                backup_device = temp;
                //Set Backup device size
                for (int i = 0; i < backup_devices_list.Count; i++)
                {
                    if (backup_devices_list[i].backup_device_name == temp)
                    {
                        backup_device_size = backup_devices_list[i].device_size;
                        file_system = backup_devices_list[i].file_system;
                        double temp_free = calculate_GB(backup_devices_list[i].device_free_space.ToString());
                        device_free_space = temp_free;
                        break;
                    }
                }
                //If no device is initialized
                if (backup_device == null || backup_device_size == 0)
                {
                    write_to_textbox(get_create_usb_instance_error(), "red");
                }
                else //If select ist successfull
                {
                    //Get Backup size
                    get_size();
                    if (backup_size < device_free_space)
                    {
                        backup_path_target = backup_device + "\Backup\";
                        Directory.CreateDirectory(backup_path_target);
                        //Get file count
                        get_file_count();
                        //Create Copy job
                        for (int i = 0; i < backup_path_source.Length; i++)
                        {
                            string backup_path_s = backup_path_source[i] + "\";
                            string backup_path_t = backup_path_target + backup_path_target_folders[i] + "\";
                            copy_function(backup_path_s, backup_path_t);
                            int progress = return_progress();
                            TextBox test = principalForm.textBox2;
                            ProgressBar progress_bar = principalForm.progressBar1;
                            //Delegate Textbox
                            if (test.InvokeRequired)
                            {
                                test.Invoke(new Action(() => test.Text = "Copying: " + backup_path_t));
                            }
                            else
                            {
                                test.Text = "Copying: " + backup_path_t;
                            }
                            //Delegate Progressbar
                            if (progress_bar.InvokeRequired)
                            {
                                test.Invoke(new Action(() => progress_bar.Value = progress));
                            }
                            else
                            {
                                progress_bar.Value = progress;
                            }
                        }

Answer 1

确保您从正确的线程进行更新。GUI 只能从其自己的线程更新。更多 这里.

Answer 2

我无法对此进行测试，但它至少应该帮助您到达那里：

private void InvokeIfRequired<C>(C control, Action<C> action) where C : Control
{
    if (control.InvokeRequired)
    {
        control.Invoke((Action)(() => action(control)));
    }
    else
    {
        action(control);
    }
}
private void backup_button_Click(object sender, EventArgs e)
{
    var principalForm = System.Windows.Forms.Application.OpenForms.OfType<Form1>().FirstOrDefault();
    if (principalForm.drive_selector.SelectedItem != null)
    {
        principalForm.backup_button.Visible = false;
        string temp = principalForm.drive_selector.SelectedItem.ToString();
        TextBox test = principalForm.textBox2;
        ProgressBar progress_bar = principalForm.progressBar1;
        Action<string> updateTest = t => this.InvokeIfRequired<TextBox>(test, c => c.Text = t);
        Action<int> updateProgress = v => this.InvokeIfRequired<ProgressBar>(progress_bar, c => c.Value = v);
        Thread backupprocess = new Thread(new ThreadStart(() => sales_backup.backup_start(temp, updateTest, updateProgress)));
        backupprocess.Start();
    }
}
//Backup Function
public void backup_start(string temp, Action<string> updateTest, Action<int> updateProgress)
{
    files_to_copy = 0;
    files_copied = 0;
    //Set Parameters
    error_copy = false;
    error_message = "";
    device_removed = false;
    //Fill variables
    temp = regex_matching_return_match(temp, @"[A-Z,a-z](:\)");
    backup_device = temp;
    //Set Backup device size
    for (int i = 0; i < backup_devices_list.Count; i++)
    {
        if (backup_devices_list[i].backup_device_name == temp)
        {
            backup_device_size = backup_devices_list[i].device_size;
            file_system = backup_devices_list[i].file_system;
            double temp_free = calculate_GB(backup_devices_list[i].device_free_space.ToString());
            device_free_space = temp_free;
            break;
        }
    }
    //If no device is initialized
    if (backup_device == null || backup_device_size == 0)
    {
        write_to_textbox(get_create_usb_instance_error(), "red");
    }
    else //If select ist successfull
    {
        //Get Backup size
        get_size();
        if (backup_size < device_free_space)
        {
            backup_path_target = backup_device + "\Backup\";
            Directory.CreateDirectory(backup_path_target);
            //Get file count
            get_file_count();
            //Create Copy job
            for (int i = 0; i < backup_path_source.Length; i++)
            {
                string backup_path_s = backup_path_source[i] + "\";
                string backup_path_t = backup_path_target + backup_path_target_folders[i] + "\";
                copy_function(backup_path_s, backup_path_t);
                int progress = return_progress();
                //Delegate Textbox
                updateTest("Copying: " + backup_path_t);
                //Delegate Progressbar
                updateProgress(progress);
            }
        }
    }
}

Answer 3

你试过使用progress_bar.Invoke((MethodInvoker)(() => progress_bar.Value = progress));吗