很想知道为什么?大家来看看!

Question

System.Drawing.Bitmap bmp = 绘图类.画图(width, height, "加总乘总K线图", als);            //第一种显示
            //为什么下面的可以正确显示？
            //Response.ContentType = "image/jpeg";
            //bmp.Save(Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);            //第二种显示
            //为什么下面就不可以正确显示？
            //Response.ContentType = "application/x-bmp";
            //bmp.Save(Response.OutputStream, System.Drawing.Imaging.ImageFormat.Bmp);            //第三种显示
            // Response.ContentType = "application/x-bmp";为什么加了这行就出错了呢？
            System.IO.MemoryStream ms = new System.IO.MemoryStream();
            bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Bmp);
            Response.BinaryWrite(ms.ToArray());
            ms.Dispose();            bmp.Dispose();

Answer 1

Response.ContentType = "application/x-bmp"； -->没有这种MIME的用法的给你参考:ez  =>  application/andrew-inset
hqx  =>  application/mac-binhex40
cpt  =>  application/mac-compactpro
doc  =>  application/msword
bin  =>  application/octet-stream
dms  =>  application/octet-stream
lha  =>  application/octet-stream
lzh  =>  application/octet-stream
exe  =>  application/octet-stream
class  =>  application/octet-stream
so  =>  application/octet-stream
dll  =>  application/octet-stream
oda  =>  application/oda
pdf  =>  application/pdf
ai  =>  application/postscript
eps  =>  application/postscript
ps  =>  application/postscript
smi  =>  application/smil
smil  =>  application/smil
mif  =>  application/vnd.mif
xls  =>  application/vnd.ms-excel
ppt  =>  application/vnd.ms-powerpoint
wbxml  =>  application/vnd.wap.wbxml
wmlc  =>  application/vnd.wap.wmlc
wmlsc  =>  application/vnd.wap.wmlscriptc
bcpio  =>  application/x-bcpio
vcd  =>  application/x-cdlink
pgn  =>  application/x-chess-pgn
cpio  =>  application/x-cpio
csh  =>  application/x-csh
dcr  =>  application/x-director
dir  =>  application/x-director
dxr  =>  application/x-director
dvi  =>  application/x-dvi
spl  =>  application/x-futuresplash
gtar  =>  application/x-gtar
hdf  =>  application/x-hdf
js  =>  application/x-javascript
skp  =>  application/x-koan
skd  =>  application/x-koan
skt  =>  application/x-koan
skm  =>  application/x-koan
latex  =>  application/x-latex
nc  =>  application/x-netcdf
cdf  =>  application/x-netcdf
sh  =>  application/x-sh
shar  =>  application/x-shar
swf  =>  application/x-shockwave-flash
sit  =>  application/x-stuffit
sv4cpio  =>  application/x-sv4cpio
sv4crc  =>  application/x-sv4crc
tar  =>  application/x-tar
tcl  =>  application/x-tcl
tex  =>  application/x-tex
texinfo  =>  application/x-texinfo
texi  =>  application/x-texinfo
t  =>  application/x-troff
tr  =>  application/x-troff
roff  =>  application/x-troff
man  =>  application/x-troff-man
me  =>  application/x-troff-me
ms  =>  application/x-troff-ms
ustar  =>  application/x-ustar
src  =>  application/x-wais-source
xhtml  =>  application/xhtml+xml
xht  =>  application/xhtml+xml
zip  =>  application/zip
au  =>  audio/basic
snd  =>  audio/basic
mid  =>  audio/midi
midi  =>  audio/midi
kar  =>  audio/midi
mpga  =>  audio/mpeg
mp2  =>  audio/mpeg
mp3  =>  audio/mpeg
aif  =>  audio/x-aiff
aiff  =>  audio/x-aiff
aifc  =>  audio/x-aiff
m3u  =>  audio/x-mpegurl
ram  =>  audio/x-pn-realaudio
rm  =>  audio/x-pn-realaudio
rpm  =>  audio/x-pn-realaudio-plugin
ra  =>  audio/x-realaudio
wav  =>  audio/x-wav
pdb  =>  chemical/x-pdb
xyz  =>  chemical/x-xyz
bmp  =>  image/bmp
gif  =>  image/gif
ief  =>  image/ief
jpeg  =>  image/jpeg
jpg  =>  image/jpeg
jpe  =>  image/jpeg
png  =>  image/png
tiff  =>  image/tiff
tif  =>  image/tiff
djvu  =>  image/vnd.djvu
djv  =>  image/vnd.djvu
wbmp  =>  image/vnd.wap.wbmp
ras  =>  image/x-cmu-raster
pnm  =>  image/x-portable-anymap
pbm  =>  image/x-portable-bitmap
pgm  =>  image/x-portable-graymap
ppm  =>  image/x-portable-pixmap
rgb  =>  image/x-rgb
xbm  =>  image/x-xbitmap
xpm  =>  image/x-xpixmap
xwd  =>  image/x-xwindowdump
igs  =>  model/iges
iges  =>  model/iges
msh  =>  model/mesh
mesh  =>  model/mesh
silo  =>  model/mesh
wrl  =>  model/vrml
vrml  =>  model/vrml
css  =>  text/css
html  =>  text/html
htm  =>  text/html
asc  =>  text/plain
txt  =>  text/plain
rtx  =>  text/richtext
rtf  =>  text/rtf
sgml  =>  text/sgml
sgm  =>  text/sgml
tsv  =>  text/tab-separated-values
wml  =>  text/vnd.wap.wml
wmls  =>  text/vnd.wap.wmlscript
etx  =>  text/x-setext
xsl  =>  text/xml
xml  =>  text/xml
mpeg  =>  video/mpeg
mpg  =>  video/mpeg
mpe  =>  video/mpeg
qt  =>  video/quicktime
mov  =>  video/quicktime
mxu  =>  video/vnd.mpegurl
avi  =>  video/x-msvideo
movie  =>  video/x-sgi-movie
ice  =>  x-conference/x-cooltalk  

Answer 2

//Response.ContentType = "application/x-bmp";
我想是不是.net中的应用类型没有这个x-bmp类型，不识别

Answer 3

在 net 2.0 中，创建的 Bitmap 的格式为 ImageFormat.MemoryBmp（通过 Bitmap 的 RawFormat 属性可以看出，
属性值为 [ImageFormat: b96b3caa-0728-11d3-9d7b-0000f81ef32e]），即Windows GDI+ 中的 ImageFormatMemoryBMP 图片格式，
看 NET 2.0 中的声明：
[TypeConverter(typeof(ImageFormatConverter))]
public sealed class ImageFormat
{
    // Fields
    private static ImageFormat bmp = new ImageFormat(new Guid("{b96b3cab-0728-11d3-9d7b-0000f81ef32e}"));
    private static ImageFormat emf = new ImageFormat(new Guid("{b96b3cac-0728-11d3-9d7b-0000f81ef32e}"));
    private static ImageFormat exif = new ImageFormat(new Guid("{b96b3cb2-0728-11d3-9d7b-0000f81ef32e}"));
    private static ImageFormat flashPIX = new ImageFormat(new Guid("{b96b3cb4-0728-11d3-9d7b-0000f81ef32e}"));
    private static ImageFormat gif = new ImageFormat(new Guid("{b96b3cb0-0728-11d3-9d7b-0000f81ef32e}"));
    private Guid guid;
    private static ImageFormat icon = new ImageFormat(new Guid("{b96b3cb5-0728-11d3-9d7b-0000f81ef32e}"));
    private static ImageFormat jpeg = new ImageFormat(new Guid("{b96b3cae-0728-11d3-9d7b-0000f81ef32e}"));
    private static ImageFormat memoryBMP = new ImageFormat(new Guid("{b96b3caa-0728-11d3-9d7b-0000f81ef32e}")); // <--- 这行
    private static ImageFormat photoCD = new ImageFormat(new Guid("{b96b3cb3-0728-11d3-9d7b-0000f81ef32e}"));
    private static ImageFormat png = new ImageFormat(new Guid("{b96b3caf-0728-11d3-9d7b-0000f81ef32e}"));
    private static ImageFormat tiff = new ImageFormat(new Guid("{b96b3cb1-0728-11d3-9d7b-0000f81ef32e}"));
    private static ImageFormat wmf = new ImageFormat(new Guid("{b96b3cad-0728-11d3-9d7b-0000f81ef32e}"));    // Methods
    public ImageFormat(Guid guid)
    {
        this.guid = guid;
    }Windows GDI+ 对图片格式的定义有：ConstantsImageFormatBMP 
Indicates the Microsoft Windows bitmap (BMP) format.ImageFormatEMF 
Indicates the Enhanced Metafile (EMF) format.ImageFormatEXIF 
Indicates the Exif (Exchangeable Image File) format.ImageFormatGIF 
Indicates the Graphics Interchange Format (GIF) format.ImageFormatIcon 
Indicates the Icon format.ImageFormatJPEG 
Indicates the JPEG format.ImageFormatMemoryBMP 
Indicates that the image was constructed from a memory bitmap.ImageFormatPNG 
Indicates the Portable Network Graphics (PNG) format.ImageFormatTIFF 
Indicates the Tagged Image File Format (TIFF) format.ImageFormatUndefined 
Indicates that Windows GDI+ is unable to determine the format.ImageFormatWMF 
Indicates the Windows Metafile Format (WMF) format.
而默认情况下，GDI+只实现  ImageFormatMemoryBMP 到 ImageFormatJPEG  的转换，要想转换为其他格式，你需要自己写编码器 Encoder。
 

Answer 4

不对吧, 我前段时间刚在做这个, 记得 .net 默认支持 5 种格式
bmp, jpeg, gif, png 都可以, 还有一个没试过, 忘了...