Asp. net 2.0 display thumbnail without refreshing picture upload concrete implementation

  • 2020-06-07 04:24:56
  • OfStack

Compatibility is not bad: FF, CH, IE, cheetah, can be achieved. If you see echo. Success, of course.

After several days of non-stop drilling, finally this 2 goods out. That was a great effort. But it was a happy moment.

Step 1: We need to load several JS libraries.
jquery library.
jquery. form. js library.

Download both libraries and reference them to the page.

Here is the JS code on the page:

  function upload() {
            var options = {
                type: "POST",                            // Of course this is the mode of transport 
                url: '../Include/Files.ashx',        //1 The path of the general handler 
                success: function (msg) {        // Parameters returned 
                    $("#server_img").attr("src", msg);            // Echo the picture. 
            //  will options To pass to ajaxForm

Step 2:1 Code in the general handler

 public void ProcessRequest(HttpContext context)
        HttpFileCollection files = context.Request.Files;              // From Gets the file object 
        if (files.Count > 0)
             string path = "";                                                            // Path string 
            Random rnd = new Random();
            for (int i = 0; i < files.Count; i++)
                HttpPostedFile file = files[i];                                        // Get the file object 
                if (file.ContentLength > 0)
                    string fileName = file.FileName;
                    string extension = Path.GetExtension(fileName);
                    int num = rnd.Next(5000, 10000);                            // The file name 
                    path = "../../UserFiles/temp/" + num.ToString() + extension;
                    file.SaveAs(System.Web.HttpContext.Current.Server.MapPath(path));        // Save the file. 
            context.Response.Write(path);            // Returns the path after the file is stored for echo. 

Step 3: The code in html or aspx.
The following two lines of code are inserted anywhere in html or aspx. I think it's possible.

    <img id="server_img" width="360px" style="border: 1px solid #ccc; padding: 2px;"   title="" alt="" />   // Used to echo images 
    <asp:FileUpload ID="Up_load" runat="server" onchange="upload()"  ontextchange="upload()"/>        // Upload images, automatically, two events to ensure that all browsers are compatible. 

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