C# Depends on the rolling of the file.

[shizuka]

It's about 20 per cent, 40 per cent, and then it hangs and rolls. client_DownloadFileCompleted I mean, how it's done, but the file isn't completely downloaded.

How do you fix that?

MessageBox.Show("Пожалуйста ожидайте начинаем процесс скачивание клиента", "тест",
 MessageBoxButtons.OK, MessageBoxIcon.Information);
WebClient client = new WebClient();
client.Proxy = null;
client.DownloadProgressChanged += new DownloadProgressChangedEventHandler(client_DownloadProgressChanged);
client.DownloadFileCompleted += new AsyncCompletedEventHandler(client_DownloadFileCompleted);
client.DownloadFileAsync(new Uri("http://***/test.7z"), @"test.7z");
void client_DownloadFileCompleted(object sender, AsyncCompletedEventArgs e)
{
    MessageBox.Show("Клиент успешно скачался,Ожидайте идет процесс распаковки.", "тест", MessageBoxButtons.OK, MessageBoxIcon.Information);

[Marcee]

You've got the processing written in such a way that it's not clear whether the async task has been successfully completed. The properties of AsyncCompletedEventArgs should be analysed.

private void DownloadCompleted(Object sender, AsyncCompletedEventArgs e)
{
    if (e.Cancelled)
    {
        //Тут обработка в случае сброса
    }
    else if (e.Error)
    {
        //Тут обработка в случае ошибки
    }
    else
    {
        MessageBox.Show("Клиент успешно скачался, Ожидайте идет процесс распаковки.", 
          "тест", MessageBoxButtons.OK, MessageBoxIcon.Information);
    }
}