WebClient with Progress bar
I am writing a small application which allows user to enter an URL then download a file on the net. In addition, I use the progress bar to show the downloading status. These code as below
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Net;
namespace DowloaderProgress
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void cmdDownload_Click(object sender, EventArgs e)
{
this.prgDownload.Maximum = 100;
WebClient myClient = new WebClient();
Uri url = new Uri(txtURL.Text);
string file = "text.pdf";
myClient.DownloadProgressChanged += new DownloadProgressChangedEventHandler(DownloadProgressCallback);
myClient.DownloadFileCompleted += new AsyncCompletedEventHandler(DownloadFileCallBack2);
//myClient.DownloadFileAsync(url, file);
}
void DownloadProgressCallback(object sender, DownloadProgressChangedEventArgs e)
{
this.prgDownload.Value = e.ProgressPercentage;
this.lblSize.Text = e.TotalBytesToReceive.ToString();
this.lblReceived.Text = e.BytesReceived.ToString();
this.lblPercent.Text = e.ProgressPercentage.ToString();
}
void DownloadFileCallBack2(object sender, AsyncCompletedEventArgs c)
{
MessageBox.Show("Download Completed");
}
}
}
However, I got the problem. If the file size is big enough, it can call the DownloadProgressCallback method so the progress bar could work, but if the file size is very small (downlading in cable network), it just call the DownloadFileCallBack2 method only. Anyone has any suggestion?
Thanks in advanced,
Chris
[1830 byte] By [
ChrisDu] at [2007-12-24]
I'm using Visual Studio 2005, Professional edition,
I've implemented this download manager, and, in my machine, the progress bar never moves, even though the file is being downloaded and in the directory the file size is increasing, however the progress bar is not moving.
Do I have to implement that form as a seperate thread? I think when the download starts the form gets jammed or something, and when I try to quit it it says (not responding) and none of the controls on the form change during the download.
Altough lblsize, lblprogress etc. should be updated while the download proceeds.
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Net;
namespace DowloaderProgress
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
// In the following procedure:
// from Microsoft MSDN Online Documentation:
// working sample url: http://www.contoso.com/logs/
// working file: January.txt
private void cmdDownload_Click(object sender, EventArgs e)
{
this.prgDownload.Maximum = 100;
WebClient myClient = new WebClient();
Uri url = new Uri(this.txtURL.Text);
string file = "January.txt"; myClient.DownloadProgressChanged += new DownloadProgressChangedEventHandler
(DownloadProgressCallback); myClient.DownloadFileCompleted +=
new AsyncCompletedEventHandler(DownloadFileCallBack2); myClient.DownloadFileAsync(url, file);
}
void DownloadProgressCallback(object sender, DownloadProgressChangedEventArgs e)
{
this.prgDownload.Value = e.ProgressPercentage;
this.lblSize.Text = e.TotalBytesToReceive.ToString();
this.lblReceived.Text = e.BytesReceived.ToString();
this.lblPercent.Text = e.ProgressPercentage.ToString();
} void DownloadFileCallBack2(object sender, AsyncCompletedEventArgs c)
{
MessageBox.Show("Download Completed");
}
}From:
new DownloadProgressChangedEventArgs(DownloadProgressCallback);
To:
new DownloadProgressChangedEventHandler(DownloadProgressCallback);
I've tested the above code and it is now updating the label.
Regards Dat.
i have do the same like you but if a file is big for ex. 200 kb
Before and during:
e.ProgressPercentage = 0
e.TotalBytesToReceive.ToString() = -1;
Then when the download is terminated:
e.ProgressPercentage = 100;
e.TotalBytesToReceive.ToString() = 200 kb;
but during the download this 2 properties don't work
Hi,man
I have the problem too.
WebClient WebIni;
Uri url;
WebIni = new WebClient();
WebIni.Credentials = new NetworkCredential("qyy","74123698"); //username and password
url = new Uri("ftp://192.168.2.6/UFDATA.MDF");
WebIni.DownloadProgressChanged += new DownloadProgressChangedEventHandler(WebIni_DownloadProgressChanged);
WebIni.DownloadFileCompleted += new AsyncCompletedEventHandler(WebIni_DownloadFileCompleted);
WebIni.DownloadFileAsync (url, "c:\\ww.dat");
}
void WebIni_DownloadProgressChanged(object sender, DownloadProgressChangedEventArgs e)
{
this.Text = "revd:" + e.BytesReceived.ToString() + " total:"
+ e.TotalBytesToReceive.ToString() + " Percent:"
+ e.ProgressPercentage.ToString()+"%";//
}
void WebIni_DownloadFileCompleted(object sender, AsyncCompletedEventArgs e)
{
MessageBox.Show("download ok");
}
I don't understand why e.TotalBytesToReceive is always -1,but BytesReceived will increase.
Who knows?
