上传图片

         

最经做了一个项目，是关于上传图片的，图片下面只有一个按钮，当数图片存在时下面按钮就出现修改图片的字样，在图片没有的时候就会出现上传图片，在外网上找了许多资料并没有合适的，后来的在无意中看到一篇关于如何隐藏  FileUploa控件来到大我们需要的效果，因此在此篇的基础上进行了一定的修改（注：原文已丢）从而实现了我需要的效果，所依在我们做项目的时候在网上找不要一样的时，我们要根据网上提供的信息发散我们的灵感进行修改，就会出现我们想要的效果~

<<<<<<<<<<<<<<<CSS中>>>>>>>>>>>>>>>>>>  

   .pic_image
        {
            margin: 5px;
            }

#pic_upload
        {
            background-color: #000000;
            left: 0;
            margin: 2px;
            opacity: 0;
            top: 0;
            color:White;
           padding-right:5px;
            }
            .opa
            {
              opacity:0;
             
             
               position:absolute;top:0px;right:9px;
height:100%;cursor:pointer; opacity:0;filter:alpha(opacity:0);z-index:999;
             }
        .file_div
        {
          margin-top:10px;
            border: 1px solid #CCCCCC;
       position:relative; overflow:hidden;
            line-height: 15px;
            text-align: center;
            width: 55px;
        }

<<<<<<<<html中>>>>>>>>>>  

    <div class="pic_image">
        <asp:Image class="picshow" ID="pic" runat="server"
            Height="84px" Width="86px" /></div>
    <div>
  
    <div class="file_div">
   
 <div  id="file_text" style="cursor:pointer"><%=strConter %></div>

 

  <asp:FileUpload ID="pic_upload" runat="server"  ToolTip="选择图片"   onchange="javascript:__doPostBack('lbUploadPhoto','')" Width="40px"             Height="19px" CssClass="opa" /> 

 </div>  

 <asp:LinkButton ID="lbUploadPhoto" runat="server" onclick="lbUploadPhoto_Click"></asp:LinkButton>

    <asp:Label ID="pic" runat="server" class="pic"></asp:Label></div>

<<<<<<<<<<<<<<<<<<lbUploadPhoto_Click>>>>>>>>>>>>>>>

 首先默认      public string strConter = "上传图片";

 

        protected void lbUploadPhoto_Click(object sender, EventArgs e)     

    {            
string id = Request["id"];

            int Id = Convert.ToInt32(id);   
          ZHXX_Child_Welfare cw = ef.GetErWelfare(Id); 
            Boolean fileOk = false;           
  //ShowMess(pic_upload.HasFile.ToString());  
           if (pic_upload.HasFile)//验证是否包含文件 
            {                
 //取得文件的扩展名,并转换成小写     
            string fileExtension = Path.GetExtension(pic_upload.FileName).ToLower();  
               //验证上传文件是否图片格式           
      fileOk = IsImage(fileExtension);

                if (fileOk)      
           {                    
 //对上传文件的大小进行检测，限定文件最大不超过8M    
       if (pic_upload.PostedFile.ContentLength < 8192000)      
               {                  
       string filepath = "/ETFL1/Upfile/";    
                     if (Directory.Exists(Server.MapPath(filepath)) == false)//如果不存在就创建file文件夹
         {  
         Directory.CreateDirectory(Server.MapPath(filepath));   
                      }                        
 string virpath = filepath + CreatePasswordHash(pic_upload.FileName, 4) + fileExtension;//这是存到服务器上的虚拟路径
          string mappath = Server.MapPath(virpath);//转换成服务器上的物理路径 
                        pic_upload.PostedFile.SaveAs(mappath);//保存图片 
                        //显示图片        
  pic.ImageUrl = virpath;

    ZHXX_Child_Welfare zcw = new ZHXX_Child_Welfare();    
                     zcw.ID = Id;                   
                              zcw.Photo = virpath;    
                     if (!string.IsNullOrEmpty(cw.Photo))   
                      {             
    int sid = ef.UpdatePhtoto(zcw);  
                           if (sid > 0)    
                         {          
                       ShowMess("修改成功！");   
                          }                            
 else                           
  {                      
           ShowMess("修改失败!"); 
                            
}                         
}                         
else                        
 {                             
int sid = ef.UpdatePhtoto(zcw);                             
if (sid > 0)                             
{                                 
ShowMess("上传成功！");                             
}                             
else                            
 {                                 
ShowMess("上传失败！");                             
}                         
}                                                                  
}                     
else                    

 {                         
pic.ImageUrl = "";                         
ShowMess("文件大小超出8M！请重新选择！");                     
}                 
}                 
else                
 {                     
ShowMess("要上传的文件类型不对！请重新选择！");                
 }             
}            
 else            
 {

           
 }         
}

   /// <summary>        
 /// 验证是否指定的图片格式         
/// </summary>         
/// <param name="str"></param>         
/// <returns></returns>         
public bool IsImage(string str)         
{             
bool isimage = false;             
string thestr = str.ToLower();             
//限定只能上传jpg和gif图片             
string[] allowExtension = { ".jpg", ".gif", ".bmp", ".png" };             
//对上传的文件的类型进行一个个匹对             
for (int i = 0; i < allowExtension.Length; i++)             
{                 
if (thestr == allowExtension[i])                 
{                     
isimage = true;                     
break;                 
}            
 }             
return isimage;        
 }

        
/// <summary>         
/// 创建一个指定长度的随机salt值         
/// </summary>        
 public string CreateSalt(int saltLenght)         
{             
//生成一个加密的随机数             
RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();             
byte[] buff = new byte[saltLenght];             
rng.GetBytes(buff);             
//返回一个Base64随机数的字符串            
 return Convert.ToBase64String(buff);         
}

        /// <summary>         
/// 返回加密后的字符串        
 /// </summary>        
 public string CreatePasswordHash(string pwd, int saltLenght)        
 {             
string strSalt = CreateSalt(saltLenght);             
//把密码和Salt连起来             
string saltAndPwd = String.Concat(pwd, strSalt);             
//对密码进行哈希            
 string hashenPwd = FormsAuthentication.HashPasswordForStoringInConfigFile(saltAndPwd, "sha1");             
//转为小写字符并截取前16个字符串             
hashenPwd = hashenPwd.ToLower().Substring(0, 16);             
//返回哈希后的值             
return hashenPwd;         
}        
 private void ShowMess(string mess)         
{            
 ScriptManager.RegisterStartupScript(this.Page, this.GetType(), "", "alert('" + mess + "')", true);         
}     
}