đoạn code trên sử dụng để download một hình ảnh về
/// <summary>
/// Function to download Image from website
/// </summary>
/// <param name="_URL">URL address to download image</param>
/// <returns>Image</returns>
public Image DownloadImage(string _URL)
{
Image _tmpImage = null;
try
{
// Open a connection
System.Net.HttpWebRequest _HttpWebRequest = (System.Net.HttpWebRequest)System.Net.HttpWebRequest.Create(_URL);
_HttpWebRequest.AllowWriteStreamBuffering = true;
// You can also specify additional header values like the user agent or the referer: (Optional)
_HttpWebRequest.UserAgent = "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1)";
_HttpWebRequest.Referer = "http://www.google.com/";
// set timeout for 20 seconds (Optional)
_HttpWebRequest.Timeout = 20000;
// Request response:
System.Net.WebResponse _WebResponse = _HttpWebRequest.GetResponse();
// Open data stream:
System.IO.Stream _WebStream = _WebResponse.GetResponseStream();
// convert webstream to image
_tmpImage = Image.FromStream(_WebStream);
// Cleanup
_WebResponse.Close();
_WebResponse.Close();
}
catch (Exception _Exception)
{
// Error
Console.WriteLine("Exception caught in process: {0}", _Exception.ToString());
return null;
}
return _tmpImage;
}
Các sử dụng
// Download web image
Image _Image = null;
_Image = DownloadImage("http://www.yourdomain.com/sample-image.jpg");
// check for valid image
if (_Image != null)
{
// show image in picturebox
pictureBox1.Image = _Image;
// lets save image to disk
_Image.Save(@"C:\SampleImage.jpg");
}
Đoạn code này sử dụng để down một file trên internet
/// <summary>
/// Function to download a file from URL and save it to local drive
/// </summary>
/// <param name="_URL">URL address to download file</param>
public void DownloadFile(string _URL, string _SaveAs)
{
try
{
System.Net.WebClient _WebClient = new System.Net.WebClient();
// Downloads the resource with the specified URI to a local file.
_WebClient.DownloadFile(_URL, _SaveAs);
}
catch (Exception _Exception)
{
// Error
Console.WriteLine("Exception caught in process: {0}", _Exception.ToString());
}
}
Sử dụng
DownloadFile("http://www.yourdomain.com/sample-file.zip", @"C:\sample-file.zip");
Sử dụng tiếp tính down load
// Occurs when an asynchronous file download operation completes.
private void _DownloadFileCompleted(object sender, AsyncCompletedEventArgs e)
{
// File download completed
download_button.Enabled = Enabled;
MessageBox.Show("Download completed");
}
// Occurs when an asynchronous download operation successfully transfers some or all of the data.
private void _DownloadProgressChanged(object sender, System.Net.DownloadProgressChangedEventArgs e)
{
// Update progress bar
progressBar1.Value = e.ProgressPercentage;
}
// download button click event
private void download_button_Click(object sender, EventArgs e)
{
// Disable download button to avoid clicking again while downloading the file
download_button.Enabled = false;
// Downloads, to a local file, the resource with the specified URI.
// This method does not block the calling thread.
System.Net.WebClient _WebClient = new System.Net.WebClient();
_WebClient.DownloadFileCompleted += new AsyncCompletedEventHandler(_DownloadFileCompleted);
_WebClient.DownloadProgressChanged += new System.Net.DownloadProgressChangedEventHandler(_DownloadProgressChanged);
_WebClient.DownloadFileAsync(new Uri("http://www.youdomain.com/sample-file.zip"), @"C:\sample-file.zip");
}
Đoạn code này thích hợp để tạo một database để lưu những đối tượng cần lưu có thể sử dụng như cache vậy
/// <summary>
/// Function to save object to external file
/// </summary>
/// <param name="_Object">object to save</param>
/// <param name="_FileName">File name to save object</param>
/// <returns>Return true if object save successfully, if not return false</returns>
public bool ObjectToFile(object _Object, string _FileName)
{
try
{
// create new memory stream
System.IO.MemoryStream _MemoryStream = new System.IO.MemoryStream();
// create new BinaryFormatter
System.Runtime.Serialization.Formatters.Binary.BinaryFormatter _BinaryFormatter
= new System.Runtime.Serialization.Formatters.Binary.BinaryFormatter();
// Serializes an object, or graph of connected objects, to the given stream.
_BinaryFormatter.Serialize(_MemoryStream, _Object);
// convert stream to byte array
byte[] _ByteArray = _MemoryStream.ToArray();
// Open file for writing
System.IO.FileStream _FileStream = new System.IO.FileStream(_FileName, System.IO.FileMode.Create, System.IO.FileAccess.Write);
// Writes a block of bytes to this stream using data from a byte array.
_FileStream.Write(_ByteArray.ToArray(), 0, _ByteArray.Length);
// close file stream
_FileStream.Close();
// cleanup
_MemoryStream.Close();
_MemoryStream.Dispose();
_MemoryStream = null;
_ByteArray = null;
return true;
}
catch (Exception _Exception)
{
// Error
Console.WriteLine("Exception caught in process: {0}", _Exception.ToString());
}
// Error occured, return null
return false;
}
Sử dụng:
ObjectToFile(pictureBox1.Image, "c:\\image-object.dat");
/// <summary>
/// Gets IP addresses of the local computer
/// </summary>
public string GetLocalIP()
{
string _IP = null;
// Resolves a host name or IP address to an IPHostEntry instance.
// IPHostEntry - Provides a container class for Internet host address information.
System.Net.IPHostEntry _IPHostEntry = System.Net.Dns.GetHostEntry(System.Net.Dns.GetHostName());
// IPAddress class contains the address of a computer on an IP network.
foreach (System.Net.IPAddress _IPAddress in _IPHostEntry.AddressList)
{
// InterNetwork indicates that an IP version 4 address is expected
// when a Socket connects to an endpoint
if (_IPAddress.AddressFamily.ToString() == "InterNetwork")
{
_IP = _IPAddress.ToString();
}
}
return _IP;
}
Ví dụ sử dụng:
Console.WriteLine("Local computer IP address : " + GetLocalIP());
Đoạn code này sử dụng để lấy ip của máy có nhiều địa chỉ ip
/// <summary>
/// Gets IP addresses object list from the local computer
/// </summary>
public System.Net.IPAddress[] GetLocalIPList()
{
// Resolves a host name or IP address to an IPHostEntry instance.
// IPHostEntry - Provides a container class for Internet host address information.
System.Net.IPHostEntry _IPHostEntry = System.Net.Dns.GetHostEntry(System.Net.Dns.GetHostName());
return _IPHostEntry.AddressList;
}
Ví dụ sử dụng:
// display all IP addresses of local machine
foreach (System.Net.IPAddress _IPAddress in GetLocalIPList())
Console.WriteLine(_IPAddress.ToString());
// display all IP addresses of local machine with addressing scheme
foreach (System.Net.IPAddress _IPAddress in GetLocalIPList())
Console.WriteLine(_IPAddress.AddressFamily.ToString() + " = " + _IPAddress.ToString());
// using System.Text.RegularExpressions;
/// <summary>
/// Regular expression built for C# on: Mon, Nov 22, 2010, 03:51:18 PM
/// Using Expresso Version: 3.0.2766, http://www.ultrapico.com
///
/// A description of the regular expression:
///
/// <img src="
/// <img
/// Space
/// src="
/// Any character that is NOT in this class: ["], any number of repetitions
/// " alt="
/// "
/// Space
/// alt="
/// [1]: A numbered capture group. [[^"]*]
/// Any character that is NOT in this class: ["], any number of repetitions
/// ">
/// ">
///
///
/// </summary>
public static Regex regex = new Regex(
"<img src=\"[^\"]*\" alt=\"([^\"]*)\">",
RegexOptions.Compiled
);
// This is the replacement string
public static string regexReplace = "$1";
//// Replace the matched text in the InputText using the replacement pattern
// string result = regex.Replace(InputText,regexReplace);
//// Split the InputText wherever the regex matches
// string[] results = regex.Split(InputText);
//// Capture the first Match, if any, in the InputText
// Match m = regex.Match(InputText);
//// Capture all Matches in the InputText
// MatchCollection ms = regex.Matches(InputText);
//// Test to see if there is a match in the InputText
// bool IsMatch = regex.IsMatch(InputText);
//// Get the names of all the named and numbered capture groups
// string[] GroupNames = regex.GetGroupNames();
//// Get the numbers of all the named and numbered capture groups
// int[] GroupNumbers = regex.GetGroupNumbers();