Multi file upload using c# on ASP.NET 4.0 environment

Question

I am looking for a solution to upload multiple files (click on browse button, and select multiple files using shift key).

I see several solutions that need to be uploaded one by one by clicking browse button, and click submit button. But I need to allow users to select multiple files at the same time.

Answer 1

We have been using the below jQuery plugin to help us.

jQuery Multiple File Upload Plugin

After including the necessary js file : jQuery.multifile.pack.js, we can use it like below.

<input type="file" id="flAttachment" runat="server" tabindex="8" class="multi max-3 accept-gif|jpg|xlsx|xls|doc|docx|pdf|png" size="37" />

Giving class="multi" makes it to accept more than one file.

You can also apply the constraints if you want. Like class = "max-3" would allow maximum three files to be uploaded. class = "accept-gif|jpg" would only allow files with gif OR jpg extensions to be uploaded.

For getting the multiple files on the sever side you will need to include the namespace : System.Web;

Then you can have the below code for iterating through each file uploaded.

if (Request.Files.Count > 0)
{
    HttpFileCollection attachments = Request.Files;
    for (int i = 0; i < attachments.Count; i++)
    {
        HttpPostedFile attachment = attachments[i];
        if (attachment.ContentLength > 0 && !String.IsNullOrEmpty(attachment.FileName))
        {
            //do your file saving or any related tasks here.
        }
    }
}

This would be regardless of .net framework version.

Answer 2

Set the property "AllowMultiple = true" as below. This property is available for 4.5 framework.

 <asp:FileUpload ID="file_upload" runat="server" AllowMultiple="true" />

This will allow you to select multiple files at one time

Aspx Code:

<form id="form1" runat="server">
    <div>
        <asp:FileUpload ID="file_upload" runat="server" AllowMultiple="true" />
        <asp:Button ID="btnFileUpload" runat="server" Text="Upload" OnClick="btnFileUpload_Click" />
        <asp:Label ID="lblUploadStatus" runat="server"></asp:Label>
    </div>
</form>

Aspx.cs Code:

protected void btnFileUpload_Click(object sender, EventArgs e)
{
    try
    {
        if (file_upload.HasFile && file_upload.PostedFiles.All(x => x.ContentType == "image/jpeg" && x.ContentLength < 102400))
        {
            foreach (var file in file_upload.PostedFiles)
            {
                file_upload.SaveAs(Server.MapPath("~/") + Path.GetFileName(file.FileName));
            }
            lblUploadStatus.Text = "File(s) uploaded successfully.";
        }
        else
        {
            lblUploadStatus.Text = "Please upload proper file.";
        }
    }
    catch (Exception ex)
    {
        lblUploadStatus.Text = "Error in uploading file." + ex.Message;
    }
}