制作最清晰缩略图的完整类(VB.NET版)

最新推荐文章于 2021-10-23 16:35:50 发布

happmaoo

最新推荐文章于 2021-10-23 16:35:50 发布

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该博客给出了一段VB.NET代码，用于图片上传与处理。代码中定义了相关变量和枚举类型，实现了图片类型检验、大文件保存、缩略图生成、小文件保存等功能，还包含删除临时文件操作，确保图片上传和处理的有效性。

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先收集一些相关资源
PublicClassClassUpPic

PrivatevPicFileAsSystem.Web.UI.HtmlControls.HtmlInputFile

PrivatevSmallPicSize,vUpFileSizeAsInteger

PrivatevUpPicPath,vNewPicName,vTmpPicNameAsString

PrivatePicMin,PicMax,vPicMaxAsSystem.Drawing.Image

PrivatePicFormatAsSystem.Drawing.Imaging.ImageFormat

PrivateMinHeight,MinWidthAsDecimal

PrivateMyfileAsIO.File

PublicSubNew(ByValPicFileAsSystem.Web.UI.HtmlControls.HtmlInputFile,ByValUpPicTypeAsPicType)

vPicFile=PicFile

vUpFileSize=HttpContext.Current.Application("UpFileSize")

SelectCaseUpPicType

CasePicType.Face

vUpPicPath="upload/images/Face"

vSmallPicSize=150

vNewPicName=HttpContext.Current.Session("MemberID")&"."&GetRightByChar(vPicFile.PostedFile.FileName,".")

CasePicType.Photo

vUpPicPath="upload/images/Photo"

vSmallPicSize=150

vNewPicName=System.Guid.NewGuid.ToString()&"."&GetRightByChar(vPicFile.PostedFile.FileName,".")

CasePicType.Pic

vUpPicPath="upload/images/Pic"

vSmallPicSize=550

vNewPicName=System.Guid.NewGuid.ToString()&"."&GetRightByChar(vPicFile.PostedFile.FileName,".")

EndSelect

EndSub

PublicFunctionGetSavedFileName()AsString

'检验图片类型=================================================================

IfvPicFile.PostedFile.FileName=""Then

ThrowNewNotSupportedException("文件为空，请您选择上传的图片文件！")

EndIf

IfLeft(vPicFile.PostedFile.ContentType,5)<>"image"Then

ThrowNewNotSupportedException("文件格式不合法，请选取有效的图片文件！"&vPicFile.PostedFile.ContentType)

EndIf

IfvPicFile.PostedFile.ContentLength>vUpFileSizeThen

DimMaxNumberAsDecimal=vUpFileSize/1024/1024

ThrowNewNotSupportedException("上传的图片文件太大,最大支持"&Format(MaxNumber,"##,##0")&"M！")

EndIf

'检验数量限制=================================================================

'保存大文件=================================================================

vPicFile.PostedFile.SaveAs(HttpContext.Current.Server.MapPath(vUpPicPath&"/max/")&vNewPicName)

vPicFile.Dispose()

'缩略图片文件=================================================================

PicMax=System.Drawing.Image.FromFile(HttpContext.Current.Server.MapPath(vUpPicPath&"/max/")&vNewPicName)

IfNot(PicMax.RawFormatIsPicFormat.GifOrPicMax.RawFormatIsPicFormat.Png)Then

IfPicMax.Height>vSmallPicSizeOrPicMax.Width>vSmallPicSizeThen

vTmpPicName=System.Guid.NewGuid.ToString()&".png"

vPicMax=PicMax

PicMax.Save(HttpContext.Current.Server.MapPath(vUpPicPath&"/max/")&vTmpPicName,PicFormat.Png)

vPicMax.Dispose()

PicMax=System.Drawing.Image.FromFile(HttpContext.Current.Server.MapPath(vUpPicPath&"/max/")&vTmpPicName)

EndIf

EndIf

'保存小文件=================================================================

GetMinPic(PicMax).Save(HttpContext.Current.Server.MapPath(vUpPicPath&"/min/")&vNewPicName,PicFormat.Jpeg)

PicMax.Dispose()

'删除临时png文件=================================================================

IfvTmpPicName<>""ThenMyfile.Delete(HttpContext.Current.Server.MapPath(vUpPicPath&"/max/")&vTmpPicName)

ReturnvNewPicName

EndFunction

PrivateFunctionGetMinPic(ByValMaxPicAsSystem.Drawing.Image)AsSystem.Drawing.Image

IfMaxPic.Height>vSmallPicSizeOrMaxPic.Width>vSmallPicSizeThen

IfMaxPic.Height>MaxPic.WidthThen

MinWidth=MaxPic.Width/(MaxPic.Height/vSmallPicSize)

MinHeight=vSmallPicSize

Else

MinWidth=vSmallPicSize

MinHeight=MaxPic.Height/(MaxPic.Width/vSmallPicSize)

EndIf

ReturnMaxPic.GetThumbnailImage(CInt(MinWidth),CInt(MinHeight),Nothing,NewSystem.IntPtr())

Else

ReturnMaxPic

EndIf

EndFunction

EnumPicType

Face=1

Photo=2

Pic=3

EndEnum

PrivateFunctionGetRightByChar(ByValStrValueAsString,ByValCharValueAsString)AsString

DimMyStr()AsString=Split(StrValue,CharValue)

ReturnMyStr(MyStr.Length-1)

EndFunction

EndClass

转自：http://guoblog.com/blogview.asp?logID=259