c#抓取网页数据( 具体分析如下实例分析C#操作图片的相关技巧(图))
优采云 发布时间: 2022-04-10 01:02c#抓取网页数据(
具体分析如下实例分析C#操作图片的相关技巧(图))
C#方法抓取当前屏幕并保存为图片
更新时间：2015-04-17 12:36:23 作者：work24
本篇文章主要介绍了C#抓取当前屏幕并保存为图片的方法，并结合实例分析了C#操作图片的相关技巧，非常实用。有需要的朋友可以参考以下
本文示例介绍了C#抓取当前屏幕并保存为图片的方法。分享给大家，供大家参考。具体分析如下：
这是一个C#实现的截屏程序，可以截取整个屏幕并保存为指定格式的图片，并将当前控制台缓存保存为文本
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Diagnostics;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading;
using System.Windows.Forms;
namespace RobvanderWoude
{
class PrintScreen
{
static int Main( string[] args )
{
try
{
string output = string.Empty;
bool overwrite = false;
bool text = false;
ImageFormat type = null;
#region Command Line parsing
if ( args.Length == 0 )
{
return WriteError( );
}
foreach ( string arg in args )
{
switch ( arg.ToUpper( ).Substring( 0, 2 ) )
{
case "/?":
return WriteError( );
case "/O":
overwrite = true;
break;
case "/T":
if ( text )
{
return WriteError( "Cannot capture current window as bitmap" );
}
switch ( arg.ToUpper( ).Substring( 3 ) )
{
case "BMP":
type = ImageFormat.Bmp;
break;
case "GIF":
type = ImageFormat.Gif;
break;
case "JPG":
case "JPEG":
type = ImageFormat.Jpeg;
break;
case "PNG":
type = ImageFormat.Png;
break;
case "TIF":
case "TIFF":
type = ImageFormat.Tiff;
break;
case "TXT":
text = true;
break;
default:
return WriteError( "Invalid file format: \"" + arg.Substring( 4 ) + "\"" );
}
break;
default:
output = arg;
break;
}
}
// Check if directory exists
if ( !Directory.Exists( Path.GetDirectoryName( output ) ) )
{
return WriteError( "Invalid path for output file: \"" + output + "\"" );
}
// Check if file exists, and if so, if it can be overwritten
if ( File.Exists( output ) )
{
if ( overwrite )
{
File.Delete( output );
}
else
{
return WriteError( "File exists; use /O to overwrite existing files." );
}
}
if ( type == null && text == false )
{
string ext = Path.GetExtension( output ).ToUpper( );
switch ( ext )
{
case ".BMP":
type = ImageFormat.Bmp;
break;
case ".GIF":
type = ImageFormat.Gif;
break;
case ".JPG":
case ".JPEG":
type = ImageFormat.Jpeg;
break;
case ".PNG":
type = ImageFormat.Png;
break;
case ".TIF":
case ".TIFF":
type = ImageFormat.Tiff;
break;
case ".TXT":
text = true;
break;
default:
return WriteError( "Invalid file type: \"" + ext + "\"" );
return 1;
}
}
#endregion Command Line parsing
if ( text )
{
string readtext = string.Empty;
for ( short i = 0; i < (short) Console.BufferHeight; i++ )
{
foreach ( string line in ConsoleReader.ReadFromBuffer( 0, i, (short) Console.BufferWidth, 1 ) )
{
readtext += line + "\n";
}
}
StreamWriter file = new StreamWriter( output );
file.Write( readtext );
file.Close( );
}
else
{
int width = Screen.PrimaryScreen.Bounds.Width;
int height = Screen.PrimaryScreen.Bounds.Height;
int top = 0;
int left = 0;
Bitmap printscreen = new Bitmap( width, height );
Graphics graphics = Graphics.FromImage( printscreen as Image );
graphics.CopyFromScreen( top, left, 0, 0, printscreen.Size );
printscreen.Save( output, type );
}
return 0;
}
catch ( Exception e )
{
Console.Error.WriteLine( e.Message );
return 1;
}
}
#region Error Handling
public static int WriteError( string errorMessage = "" )
{
Console.ResetColor( );
if ( string.IsNullOrEmpty( errorMessage ) == false )
{
Console.Error.WriteLine( );
Console.ForegroundColor = ConsoleColor.Red;
Console.Error.Write( "ERROR: " );
Console.ForegroundColor = ConsoleColor.White;
Console.Error.WriteLine( errorMessage );
Console.ResetColor( );
}
Console.Error.WriteLine( );
Console.Error.WriteLine( "PrintScreen, Version 1.10" );
Console.Error.WriteLine( "Save a screenshot as image or save the current console buffer as text" );
Console.Error.WriteLine( );
Console.Error.Write( "Usage: " );
Console.ForegroundColor = ConsoleColor.White;
Console.Error.WriteLine( "PRINTSCREEN outputfile [ /T:type ] [ /O ]" );
Console.ResetColor( );
Console.Error.WriteLine( );
Console.Error.Write( "Where: " );
Console.ForegroundColor = ConsoleColor.White;
Console.Error.Write( "outputfile" );
Console.ResetColor( );
Console.Error.WriteLine( " is the file to save the screenshot or text to" );
Console.ForegroundColor = ConsoleColor.White;
Console.Error.Write( " /T:type" );
Console.ResetColor( );
Console.Error.Write( " specifies the file type: " );
Console.ForegroundColor = ConsoleColor.White;
Console.Error.Write( "BMP" );
Console.ResetColor( );
Console.Error.Write( ", " );
Console.ForegroundColor = ConsoleColor.White;
Console.Error.Write( "GIF" );
Console.ResetColor( );
Console.Error.Write( ", " );
Console.ForegroundColor = ConsoleColor.White;
Console.Error.Write( "JPG" );
Console.ResetColor( );
Console.Error.Write( ", " );
Console.ForegroundColor = ConsoleColor.White;
Console.Error.Write( "PNG" );
Console.ResetColor( );
Console.Error.Write( ", " );
Console.ForegroundColor = ConsoleColor.White;
Console.Error.Write( "TIF" );
Console.ResetColor( );
Console.Error.Write( " or " );
Console.ForegroundColor = ConsoleColor.White;
Console.Error.WriteLine( "TXT" );
Console.ResetColor( );
Console.Error.Write( " (only required if " );
Console.ForegroundColor = ConsoleColor.White;
Console.Error.Write( "outputfile" );
Console.ResetColor( );
Console.Error.WriteLine( " extension is different)" );
Console.ForegroundColor = ConsoleColor.White;
Console.Error.Write( " /O" );
Console.ResetColor( );
Console.Error.WriteLine( " overwrites an existing file" );
Console.Error.WriteLine( );
Console.Error.Write( "Credits: Code to read console buffer by Simon Mourier " );
Console.ForegroundColor = ConsoleColor.DarkGray;
Console.Error.WriteLine( "http://www.sina.com.cn" );
Console.ResetColor( );
Console.Error.Write( " Code for graphic screenshot by Ali Hamdar " );
Console.ForegroundColor = ConsoleColor.DarkGray;
Console.Error.WriteLine( "https://www.jb51.net" );
Console.ResetColor( );
Console.Error.WriteLine( );
Console.Error.WriteLine( "Written by Rob van der Woude" );
Console.Error.WriteLine( "http://www.qq.com" );
return 1;
}
#endregion Error Handling
}
#region Read From Console Buffer
public class ConsoleReader
{
public static IEnumerable ReadFromBuffer( short x, short y, short width, short height )
{
IntPtr buffer = Marshal.AllocHGlobal( width * height * Marshal.SizeOf( typeof( CHAR_INFO ) ) );
if ( buffer == null )
throw new OutOfMemoryException( );
try
{
COORD coord = new COORD( );
SMALL_RECT rc = new SMALL_RECT( );
rc.Left = x;
rc.Top = y;
rc.Right = (short) ( x + width - 1 );
rc.Bottom = (short) ( y + height - 1 );
COORD size = new COORD( );
size.X = width;
size.Y = height;
const int STD_OUTPUT_HANDLE = -11;
if ( !ReadConsoleOutput( GetStdHandle( STD_OUTPUT_HANDLE ), buffer, size, coord, ref rc ) )
{
// 'Not enough storage is available to process this command' may be raised for buffer size > 64K (see ReadConsoleOutput doc.)
throw new Win32Exception( Marshal.GetLastWin32Error( ) );
}
IntPtr ptr = buffer;
for ( int h = 0; h < height; h++ )
{
StringBuilder sb = new StringBuilder( );
for ( int w = 0; w < width; w++ )
{
CHAR_INFO ci = (CHAR_INFO) Marshal.PtrToStructure( ptr, typeof( CHAR_INFO ) );
char[] chars = Console.OutputEncoding.GetChars( ci.charData );
sb.Append( chars[0] );
ptr += Marshal.SizeOf( typeof( CHAR_INFO ) );
}
yield return sb.ToString( );
}
}
finally
{
Marshal.FreeHGlobal( buffer );
}
}
[StructLayout( LayoutKind.Sequential )]
private struct CHAR_INFO
{
[MarshalAs( UnmanagedType.ByValArray, SizeConst = 2 )]
public byte[] charData;
public short attributes;
}
[StructLayout( LayoutKind.Sequential )]
private struct COORD
{
public short X;
public short Y;
}
[StructLayout( LayoutKind.Sequential )]
private struct SMALL_RECT
{
public short Left;
public short Top;
public short Right;
public short Bottom;
}
[StructLayout( LayoutKind.Sequential )]
private struct CONSOLE_SCREEN_BUFFER_INFO
{
public COORD dwSize;
public COORD dwCursorPosition;
public short wAttributes;
public SMALL_RECT srWindow;
public COORD dwMaximumWindowSize;
}
[DllImport( "kernel32.dll", SetLastError = true )]
private static extern bool ReadConsoleOutput( IntPtr hConsoleOutput, IntPtr lpBuffer, COORD dwBufferSize, COORD dwBufferCoord, ref SMALL_RECT lpReadRegion );
[DllImport( "kernel32.dll", SetLastError = true )]
private static extern IntPtr GetStdHandle( int nStdHandle );
}
#endregion Read From Console Buffer
}
我希望这篇文章对你的 C# 编程有所帮助。
