图片上传时应该注意的内容

封面图片上传：<asp:FileUpload ID="FileUpload1" runat="server" οnchange="DisplayImage(this);" />
上传按钮：<asp:Button ID="Button1" runat="server" OnClientClick="return CheckImg(document.getElementById('FileUpload1'))"
                OnClick="Button1_Click" Text="上传" /><br />
文件路径:<asp:Label ID="Label1" runat="server" Text="Label"></asp:Label><br />
大小:<asp:Label ID="Label2" runat="server" Text="Label"></asp:Label>
上传图片：<asp:Image ID="Image1" runat="server" />

 <script type="text/javascript">  
    function CheckImg(FileUpload)
    {
 var mime=FileUpload.value;
        mime=mime.toLowerCase().substr(mime.lastIndexOf("."));
     if(mime!=".jpg")
     {
      FileUpload.value="";
      alert("仅支持JPG格式");
      return false;
     }
    }
   
    function DisplayImage(FileUpload)
    {
        var mime=FileUpload.value;  
        document.getElementById("aa").src = mime;
    }
    </script>

protected void Button1_Click(object sender, EventArgs e)
    {
        //判断有没有文件上传
        if (this.FileUpload1.HasFile)
        {
            //得到文件名
            string fileName = this.FileUpload1.PostedFile.FileName;
            int fileSize = this.FileUpload1.PostedFile.ContentLength;

            this.Label1.Text = fileName;
            this.Label2.Text = fileSize.ToString();

            //真正上传到 UpLoad文件夹下面
            string saveFileName = DateTime.Now.ToString("yyyyMMddHHmmss")
            + System.IO.Path.GetExtension(fileName);

            //上传
            saveFileName = "~/UpLoad/" + saveFileName;

            //要求用物理路径, 实现上传
            this.FileUpload1.PostedFile.SaveAs( MapPath(saveFileName ) );

           this.Image1.ImageUrl = saveFileName;

        }
    }

这个方法是按上传按钮就会显示出所有的信息不是跨页跳转的实现。

 

实现跨页提交用session保存图片的信息

<asp:FileUpload ID="FileUpload1" runat="server" οnchange="CheckImg(this)"/>
<asp:Button ID="Button1" runat="server" Text="上传" OnClick="Button1_Click" Width="57px" />

<script type="text/javascript">
        function CheckImg(FileUpLoad){
           var mime=FileUpLoad.value;
           mime=mime.toLowerCase().substr(mime.lastIndexOf("."));
           if(mime!=".jpg"){
            FileUpLoad.value="";
            alert("图片必须为.JPG格式！");
            return;
           }
        }
</script>

 protected void Button1_Click(object sender, EventArgs e)
        {
            string fileName = this.FileUpload1.PostedFile.FileName;
            string saveName = DateTime.Now.ToString("yyyyMMddHHmmss") + System.IO.Path.GetExtension(fileName);
            saveName = "~/UpLoad/" + saveName;
            this.FileUpload1.PostedFile.SaveAs(MapPath(saveName));
            Session["saveName"] = saveName;
        }

显示页面获取session中的对象    string text = Session["saveName"].ToString();
                           this.Image1.ImageUrl = text;