Previously, the thumbnail on the page must be used to use a third party component. Now, with .NET, thumbnails can be easily implemented. Below is an example of achieving thumbnails.
Keywords: C #, ASP.NET, thumbnail
Example Download: http://www.lionsky.net/mywebsite/downsoft/list.aspx? Id = 221
TOTHUMBNAILIMAGE.ASPX
<% @ Page language = "c #" Codebehind = "ToThumbnailImage.aspx.cs" Src = "ToThumbnailImage.aspx.cs" AutoEventWireup = "false" Inherits = "Exam_C.ToThumbnailImage"%>
Lion Interactive Network => Generate Thumbnail </ Title> </ head> <body> <form id = "form1" method = "post" runat = "server"> </ form> </ body> </ html></p>
<p>TOTHUMBNAILIMAGE.ASPX.CS</p>
<p>using System; using System.Collections; using System.ComponentModel; using System.Data; using System.Drawing; using System.Web; using System.Web.SessionState; using System.Web.UI; using System.Web.UI.WebControls Using system.Web.ui.htmlControls; Using System.drawing.Imaging; Namespace Exam_c {/// <summary> /// TothumbnailImage Summary Description. /// </ summary> public class tothumbnailimage: system.Web.ui.page {/ * create by lion 2003-05-20 19:00 Copyright (c) 2004 www.lionsky.net. All Rights Reserved. Web: http : //www.lionsky.net; email: lion-a@sohu.com * /</p>
<p>Static hashtable htmimes = new hashtable (); internal readonly string allowext = ".jpe | .jpeg | .jpg | .png | .tif | .tiff | .bmp"; #REGON Web Form Designer Generated Code Override Protected Void OnInit (Eventargs E) {#Region Htmimes ["JPE"] = "image / jpeg"; htmimes ["jpeg"] = "image / jpeg"; htmimes ["jpg"] = "image / jpeg"; HTMIMES ["PNG"] = "image / png"; htmimes [". TIF"] = "image / TIFF"; htmimes ["TIFF"] = "image / TIFF"; htmimes [". BMP"] = "image / bmp"; #ndregion // Call generation thumbnail method TothumbnailImages, "B.GIF", 300);} # endregion # region helper /// <summary> /// Get image encoding All related information of the decoder /// </ summary> /// <param name = "MIMETYPE"> Contains a multi-purpose Internet Snail Extension Protocol (MIME) type of the encoded decoder </ param> /// < returns> returns all image codec information </ returns> static ImageCodecInfo GetCodecInfo (string mimeType) {ImageCodecInfo [] CodecInfo = ImageCodecInfo.GetImageEncoders (); foreach (ImageCodecInfo ici in CodecInfo) {if (ici.MimeType == mimeType Return ICI;} return null;}</p>
<p>/// <summary> /// detects the validity of the extension /// </ summary> /// <param name = "sext"> file name extension </ param> /// <returns> If the extension Effective, return true, otherwise returning false. </ Returns> BOOL CheckvaliDext (String sext) {bool flag = false; string [] ate = allowext.split ('|'); foreach (string filetype in aext) {ix .Tolower () == sext) {flag = true; Break;}} Return Flag;</p>
<p>/// <summary> /// Save Picture /// <//// <param name = "image"> image object </ param> /// <param name = "savepath"> save the path </ param> /// <param name = "ici"> parameter specifies codec format </ param> void SaveImage (System.Drawing.Image image, string savePath, ImageCodecInfo ici) {// set the object original image object EncoderParameters EncoderParameters Parameters = New EncoderParameters (1); parameters.Param [0] = new encoderparameter (Encoder.quality, ((long) 90)); Image.Save (SavePath, ICI, Parameters); parameters.dispose ();} #ENDREGION #Region Methods</p>
<p>/// <summary> /// Generate thumbnail /// </ summary> /// <param name = "sourceImagePath"> original image path (relative path) </ param> /// <parame = "thumbnailimagePath "> The resulting thumbnail path, if saved as the original picture path (relative path) </ param> /// <param name =" thumbnailimageWidth "> The width of the thumbnail (height is automatically generated by the source image proportion) </ param> public void ToThumbnailImages (string sourceImagePath, string thumbnailImagePath, int thumbnailImageWidth) {string sourceImagePath = sourceImagePath; string thumbnailImagePath = thumbnailImagePath; int thumbnailImageWidth = thumbnailImageWidth; string sExt = SourceImagePath.Substring ( "." SourceImagePath.LastIndexOf ()). ToLower (); if (SourceImagePath.ToString () == System.String.Empty) throw new NullReferenceException ( "SourceImagePath is null!"); (! CheckValidExt (sExt)) if {throw new ArgumentException ( "the original image file format does not Correctly, supported formats have [" Allowext "] "," SourceImagePath ");} // Create an Image object from the original image System.drawing.Image.fromfile (httpContext.current.server. Mappath (SourceImagePath)); int Num = ((thumbnailimagewidth / 4) * 3) Int width = image.width; int Height = image.Height; // Calculate the proportion of pictures IF ((Double) Width) / ((Double) Height)> = 1.333333333333331F) {Num = ((Height * ThumbnailimageWidth) / width);} else {thumbnailimageWidth = (width * Num) / height);}} ((ThumbnailImageWidth <1) || (Num <1)) {return;} // initialize with the specified size and format BitMap class Bitmap Bitmap = New Bitmap (thumbnailimagewidth, num, pixelformat.format32bppargb); // Create a new Graphics object from the specified image object graphics graphics = graphics.FromImage (Bitmap);</p>
<p>/ / Clear the entire drawing and populate graphics.clear (color.TransParent) in transparent background; // Draw the original picture object in the specified location and press the specified size (Image, New Rectangle (0, 0, ThumbnailImageWidth, Num )); image.Dispose (); try {// this original image to the specified format and saved with the specified codec parameter to specify the file string savepath = (ThumbnailImagePath == null SourceImagePath:? ThumbnailImagePath); SaveImage (bitmap, HttpContext. CURRENT.SERVER.MAPPATH (SavePath), getCodecInfo ((String) htmimes [sext]));} catch (system.exception e) {throw e;} finally {bitmap.dispose (); graphics.dispose ();}} #ndregion}}}</p>
<p>Source: http://blog.9cbs.net/houjianxun/archive/2004/07/07/AAAAA.ASPX</p></div><div class="text-center mt-3 text-grey">
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var debug = DEBUG = 0;
var url_rewrite_on = 1;
var url_path = './';
var forumarr = {"1":"Tech"};
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function resize_image() {
var jmessagelist = $('div.message');
var first_width = jmessagelist.width();
jmessagelist.each(function() {
var jdiv = $(this);
var maxwidth = jdiv.attr('isfirst') ? first_width : jdiv.width();
var jmessage_width = Math.min(jdiv.width(), maxwidth);
jdiv.find('img, embed, iframe, video').each(function() {
var jimg = $(this);
var img_width = this.org_width;
var img_height = this.org_height;
if(!img_width) {
var img_width = jimg.attr('width');
var img_height = jimg.attr('height');
this.org_width = img_width;
this.org_height = img_height;
}
if(img_width > jmessage_width) {
if(this.tagName == 'IMG') {
jimg.width(jmessage_width);
jimg.css('height', 'auto');
jimg.css('cursor', 'pointer');
jimg.on('click', function() {
});
} else {
jimg.width(jmessage_width);
var height = (img_height / img_width) * jimg.width();
jimg.height(height);
}
}
});
});
}
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$('div.message').each(function() {
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jdiv.find('table').addClass('table').wrap('<div class="table-responsive"></div>');
});
}
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resize_image();
resize_table();
$(window).on('resize', resize_image);
});
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