asp.net如何生成缩略图

2019-08-09 05:49:40来源：爱站网阅读 ()

asp.net如何生成缩略图？asp.net生成缩略图就是指我们给出指定图片，生成后存放的服务器路径就会成为缩略图，那么我们现在就去看看ASP.NET生成缩略图的代码介绍吧。?

复制代码代码如下:

using System;

using System.Data;

using System.Configuration;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Web.UI.HtmlControls;

using System.IO;

using System.Drawing;

using System.Drawing.Imaging;

/// <summary>

/// 图片处理类

/// 1、生成缩略图片或按照比例改变图片的大小和画质

/// 2、将生成的缩略图放到指定的目录下

/// </summary>

public class ImageClass

{

public System.Drawing.Image ResourceImage;

private int ImageWidth;

private int ImageHeight;

public string ErrMessage;

/// <summary>

/// 类的构造函数

/// </summary>

/// <param name="ImageFileName">图片文件的全路径名称</param>

public ImageClass(string ImageFileName)

{

ResourceImage = System.Drawing.Image.FromFile(ImageFileName);

ErrMessage = "";

}

public bool ThumbnailCallback()

{

return false;

}

/// <summary>

/// 生成缩略图重载方法1，返回缩略图的Image对象

/// </summary>

/// <param name="Width">缩略图的宽度</param>

/// <param name="Height">缩略图的高度</param>

/// <returns>缩略图的Image对象</returns>

public System.Drawing.Image GetReducedImage(int Width, int Height)

{

try

{

System.Drawing.Image ReducedImage;

System.Drawing.Image.GetThumbnailImageAbort callb = new System.Drawing.Image.GetThumbnailImageAbort(ThumbnailCallback);

ReducedImage = ResourceImage.GetThumbnailImage(Width, Height, callb, IntPtr.Zero);

return ReducedImage;

}

catch (Exception e)

{

ErrMessage = e.Message;

return null;

}

}

/// <summary>

/// 生成缩略图重载方法2，将缩略图文件保存到指定的路径

/// </summary>

/// <param name="Width">缩略图的宽度</param>

/// <param name="Height">缩略图的高度</param>

/// <param name="targetFilePath">缩略图保存的全文件名，(带路径)，参数格式：D:Images ilename.jpg</param>

/// <returns>成功返回true，否则返回false</returns>

public bool GetReducedImage(int Width, int Height, string targetFilePath)

{

try

{

System.Drawing.Image ReducedImage;

System.Drawing.Image.GetThumbnailImageAbort callb = new System.Drawing.Image.GetThumbnailImageAbort(ThumbnailCallback);

ReducedImage = ResourceImage.GetThumbnailImage(Width, Height, callb, IntPtr.Zero);

ReducedImage.Save(@targetFilePath, ImageFormat.Jpeg);

ReducedImage.Dispose();

return true;

}

catch (Exception e)

{

ErrMessage = e.Message;

return false;

}

}

/// <summary>

/// 生成缩略图重载方法3，返回缩略图的Image对象

/// </summary>

/// <param name="Percent">缩略图的宽度百分比 如：需要百分之80，就填0.8</param>

/// <returns>缩略图的Image对象</returns>

public System.Drawing.Image GetReducedImage(double Percent)

{

try

{

System.Drawing.Image ReducedImage;

System.Drawing.Image.GetThumbnailImageAbort callb = new System.Drawing.Image.GetThumbnailImageAbort(ThumbnailCallback);

ImageWidth = Convert.ToInt32(ResourceImage.Width * Percent);

ImageHeight = Convert.ToInt32(ResourceImage.Width * Percent);

ReducedImage = ResourceImage.GetThumbnailImage(ImageWidth, ImageHeight, callb, IntPtr.Zero);

return ReducedImage;

}

catch (Exception e)

{

ErrMessage = e.Message;

return null;

}

}

/// <summary>

/// 生成缩略图重载方法4，返回缩略图的Image对象

/// </summary>

/// <param name="Percent">缩略图的宽度百分比 如：需要百分之80，就填0.8</param>

/// <param name="targetFilePath">缩略图保存的全文件名，(带路径)，参数格式：D:Images ilename.jpg</param>

/// <returns>成功返回true,否则返回false</returns>

public bool GetReducedImage(double Percent, string targetFilePath)

{

try

{

System.Drawing.Image ReducedImage;

System.Drawing.Image.GetThumbnailImageAbort callb = new System.Drawing.Image.GetThumbnailImageAbort(ThumbnailCallback);

ImageWidth = Convert.ToInt32(ResourceImage.Width * Percent);

ImageHeight = Convert.ToInt32(ResourceImage.Width * Percent);

ReducedImage = ResourceImage.GetThumbnailImage(ImageWidth, ImageHeight, callb, IntPtr.Zero);

ReducedImage.Save(@targetFilePath, ImageFormat.Jpeg);

ReducedImage.Dispose();

return true;

}

catch (Exception e)

{

ErrMessage = e.Message;

return false;

}

}

}