asp.net2.0 上传图片(FileUpload控件) 并生成缩略图

记录，备忘：

（1）

using System.IO; //添加

（2）

在页面上放入一个FileUpload控件，id为“FileUpload1”，和一个“上传”按钮，id为“btnUpload”。

/// <summary>
///"上传"按钮
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
protected void btnUpload_Click(object sender, EventArgs e)
{
    string serverPath = Server.MapPath("~/images/product");//设置图片路径

    if(this.FileUpload1.HasFile)
    {
        string name=FileUpload1.FileName;
        string fName = this.txtImageName.Text; //新的图片名称，不填则使用原图片名
        //string type=fName.Substring(fName.LastIndexOf(".")+1).ToLower();

string type = name.Substring(name.LastIndexOf(".") + 1).ToLower();

if(string.IsNullOrEmpty(fName)) 

        {
            fName = name;
        }
       else 

    fName += "." + type;

 

if(type == "jpg"|| type == "png"|| type == "bmp"|| type == "gif"|| type == "jpeg")
        {
            UpLoadImage(serverPath,fName);//执行上传图片，并生成缩略图
        }
        else
       {
            HttpContext.Current.Response.Write("<script>alert('图片格式不对!');</script>");
            return;
        }
    }
    else
   {
        HttpContext.Current.Response.Write(" <script>alert('请选择要上传的文件') </script>");
        return;
    }
    HttpContext.Current.Response.Write(" <script>alert('文件上传成功') </script>");
}

/// <summary>
///执行上传图片操作，并生成缩略图
/// </summary>
/// <param name="serverPath"></param>
/// <param name="fName"></param>
private voidUpLoadImage(stringserverPath, stringfName)
{
    if(!File.Exists(serverPath))
    {
         Directory.CreateDirectory(serverPath);
         Directory.CreateDirectory(serverPath + "_thumb");
    }
    stringfPath = serverPath + "\\"+ fName;//文件实际路径

    Stringtpath = serverPath + "_thumb\\"+ fName;//缩略图路径 

    if(!File.Exists(tpath) && !File.Exists(fPath))
    {       
         this.FileUpload1.SaveAs(fPath);//上传到图片路径       
         ImageClass.MakeThumbnail(fPath, tpath, 180, 117, "w"); //调用ImageClass类的MakeThumbnail()方法，生成缩略图
         this.myImage.ImageUrl = "~/images/product_thumb"+ "\\"+ fName;
    }
    else
   {
         HttpContext.Current.Response.Write("<script>alert('图片已存在!');</script>");
         return;
    }
}

（3）ImageClass类（转，网址忘记了）

//add
usingSystem.Data;
usingSystem.Configuration;
usingSystem.Web.UI;
usingSystem.IO;

/// <summary>
///生成缩略图
/// </summary>
/// <param name="originalImagePath">源图路径（物理路径）</param>
/// <param name="thumbnailPath">缩略图路径（物理路径）</param>
/// <param name="width">缩略图宽度</param>
/// <param name="height">缩略图高度</param>
/// <param name="mode">生成缩略图的方式</param> 
public static voidMakeThumbnail(stringoriginalImagePath, stringthumbnailPath, intwidth, intheight, stringmode)
{
    System.Drawing.ImageoriginalImage = System.Drawing.Image.FromFile(originalImagePath);

    inttowidth = width;
    inttoheight = height;

    intx = 0;
    inty = 0;
    intow = originalImage.Width;
    intoh = originalImage.Height;

    if(ow < towidth && oh < toheight)
    {
        originalImage.Save(thumbnailPath);
    }
    else
   {

        switch(mode.ToUpper())
        {
            case"HW"://指定高宽缩放（可能变形）         
                break;
            case"W"://指定宽，高按比例           
                toheight = originalImage.Height * width / originalImage.Width;
                break;
            case"H"://指定高，宽按比例
                towidth = originalImage.Width * height / originalImage.Height;
                break;
            case"CUT"://指定高宽裁减（不变形）         
                if((double)originalImage.Width / (double)originalImage.Height > (double)towidth / (double)toheight)
                {
                    oh = originalImage.Height;
                    ow = originalImage.Height * towidth / toheight;
                    y = 0;
                    x = (originalImage.Width - ow) / 2;
                }
                else
               {
                    ow = originalImage.Width;
                    oh = originalImage.Width * height / towidth;
                    x = 0;
                    y = (originalImage.Height - oh) / 2;
                }
                break;
            case"AUTO": //自动适应高度
                if(ow > oh)
                {
                    //newwidth = 200;
                   toheight = (int)((double)oh / (double)ow * (double)towidth);
                }
                else
               {
                    //newheight = 200;
                   towidth = (int)((double)ow / (double)oh * (double)toheight);
                }
                break;
            default:
                break;
        }

        //新建一个bmp图片
        System.Drawing.Imagebitmap = newSystem.Drawing.Bitmap(towidth, toheight);

        //新建一个画板
        System.Drawing.Graphicsg = System.Drawing.Graphics.FromImage(bitmap);

        //设置高质量插值法
        g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;

        //设置高质量,低速度呈现平滑程度
        g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

        //清空画布并以透明背景色填充
        g.Clear(System.Drawing.Color.Transparent);

        //在指定位置并且按指定大小绘制原图片的指定部分
        g.DrawImage(originalImage, newSystem.Drawing.Rectangle(0, 0, towidth, toheight),
            newSystem.Drawing.Rectangle(x, y, ow, oh),
            System.Drawing.GraphicsUnit.Pixel);

        try
       {
            //以jpg格式保存缩略图
            bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);

        }
        catch(System.Exceptione)
        {
            throwe;
        }
        finally
       {

            bitmap.Dispose();
            g.Dispose();
        }
    }
    originalImage.Dispose();
}