FileUpload上床图片，怎么判断这是不是一个图片类型
public bool CheckImgFormat(string fileExt, string contentType) { string Extlist = ".BMP.GIF.JPEG.JPG.PNG"; if (Extlist.IndexOf(fileExt) == -1) { return false; } else { string conType = "image/pjpeg image/gif image/bmp image/x-png image/tiff image/png image/jpeg"; if (conType.IndexOf(contentType) == -1) { return false; } else { return true; } } }String fileExtension = System.IO.Path.GetExtension(FileUpload1.FileName).ToLower();//获取文件扩展名 String[] allowedExtensions = { ".gif", ".png", ".jpeg", ".jpg" }; //允许上传的文件格式 for (int i = 0; i < allowedExtensions.Length; i++) { if (fileExtension == allowedExtensions[i]) { fileOK = true; break; }
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例子
<%@ Page Language="C#" EnableEventValidation="false" EnableViewState="true" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><script runat="server">private bool IsAllowedExtension(String filePath){ bool ret = false; System.IO.FileStream fs = new System.IO.FileStream(filePath, System.IO.FileMode.Open, System.IO.FileAccess.Read); System.IO.BinaryReader r = new System.IO.BinaryReader(fs); string fileclass = ""; byte buffer; try { buffer = r.ReadByte(); fileclass = buffer.ToString(); buffer = r.ReadByte(); fileclass += buffer.ToString(); } catch { return false; } r.Close(); fs.Close(); /*文件扩展名说明 *4946/104116 txt *7173 gif *255216 jpg *13780 png *6677 bmp *239187 txt,aspx,asp,sql *208207 xls.doc.ppt *6063 xml *6033 htm,html *4742 js *8075 xlsx,zip,pptx,mmap,zip *8297 rar *01 accdb,mdb *7790 exe,dll *5666 psd *255254 rdp *10056 bt种子 *64101 bat *4059 sgf */ String[] fileType = { "255216", "7173", "6677", "13780" }; String[] fileExtName = { "jpg", "gif", "bmp", "png" }; /* //纯图片 String[] fileType = { "7173", //gif "255216", //jpg "13780" //png }; */ String fExt = ""; for (int i = 0; i < fileType.Length; i++) { if (fileclass == fileType[i]) { fExt = fileExtName[i]; ret = true; break; } } System.Web.HttpContext.Current.Response.Write(fExt);//可以在这里输出你不知道的文件类型的扩展名 return ret;} protected void Button1_Click(object sender, EventArgs e) { String g = System.Guid.NewGuid().ToString("D"); FileUpload1.SaveAs(Server.MapPath("~/" + g + ".tmp")); if (IsAllowedExtension(Server.MapPath("~/" + g + ".tmp"))) { FileUpload1.SaveAs(Server.MapPath("~/x.jpg")); } System.IO.File.Delete(Server.MapPath("~/" + g + ".tmp")); }</script><html xmlns="http://www.w3.org/1999/xhtml"><head id="Head1" runat="server"> <title></title></head><body> <form runat="server" id="form1"> <asp:FileUpload ID="FileUpload1" runat="server" /> <asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Button" /> </form></body></html>
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<script language="javascript" type="text/javascript"> function Show() { var x = ""; var y = document.getElementById("FileUpload1"); if (!x || !y.value || !y) return; var pt = /\.jpg$|\.gif$|\.bmp$/i; if (pt.test(y.value)) { //alert("file://" + y.value); x = "file://" + y.value; } else { alert("您似乎选择的不是图片!为了避免错误.请重新选择."); document.getElementById("FileUpload1").value = ""; return false; } } function pd() { if (document.getElementById("FileUpload1").value == "") { alert("请选择一张图片上传！"); return false; } if (document.getElementById("TextBox1").value == "") { alert("请填写标题！"); return false; } } </script>
[解决办法]
string imageurl = @"G:\图片\wb.jpg"; int i = imageurl.LastIndexOf('.'); string newstr = imageurl.Substring(i+1); FileStream Fs = new FileStream(imageurl, FileMode.Open, FileAccess.Read); BinaryReader rdr = new BinaryReader(Fs); string fileClass; byte buffer; buffer = rdr.ReadByte(); fileClass = buffer.ToString(); buffer = rdr.ReadByte(); fileClass += buffer.ToString(); rdr.Close(); Fs.Close(); //Common.MessageBox.MsgBox(this, fileClass.ToString()); string trueimage = ""; switch(fileClass)//255216是jpg;7173是gif;6677是BMP,13780是PNG; { case "255216": trueimage = "jpg"; break; case "7173": trueimage = "gif"; break; case "6677": trueimage = "bmp"; break; case "13780": trueimage = "png"; break; }
[解决办法]
http://blog.csdn.net/fengyarongaa/article/details/6640211
[解决办法]
ArrayList ImgType = new ArrayList(); excelType.Add("image/x-jg");excelType.Add("image/bmp");excelType.Add("image/gif");excelType.Add("image/ief");excelType.Add("image/jpeg");excelType.Add("image/x-macpaint");excelType.Add("image/png"); if (ImgType .Contains(fileUpload1.PostedFile.ContentType))//判断是否是刚才定义的图片类型 {}