Introduction
In this article I have explained how to upload multiple files using file upload control. I have used jQuery plugin for uploading multiple files.
I have also explained how to check for file type, file maximum size limit using jQuery & also using server side validation code.
Download the Following Files
Namespace used
using System.Security.Cryptography;
using System.Text;
using System.IO;
Step 1: Include the jQuery Files needed on the page.
Assuming you have downloaded these files, create a reference to these files in the <head> section of your page as shown below:
<head id="Head1" runat="server">
<title>Multiple File Upload using JQuery</title>
<script src="Scripts/jquery-1.3.2.js"
type="text/javascript">
</script>
<script src="Scripts/jquery.MultiFile.js"
type="text/javascript">
</script>
</head>
Step 2: Add File Upload Control & Button on the Page.
<asp:FileUpload ID="FileUpload1" runat="server"
class="multi" accept="gif|jpeg|bmp|png|jpg"
maxlength="5" />
<br />
<asp:Button ID="btnUpload" runat="server"
Text="Upload All" OnClick="btnUpload_Click" />
<br />
<asp:Label ID="lblMsg" runat="server" Text="">\
</asp:Label>
class=”multi” is used to specify that user can select multiple files.
maxlength property specify that user can upload maximum 5 files not more than that.
accept property used to restrict user to upload only certain type of file only.
Step 3: Double click on Upload Button & Write the code that is used to upload files.
protected void btnUpload_Click(object sender, EventArgs e)
{
if (ServerSideValidation() == true)
{
string SavePath, Msg = null;
// Get the HttpFileCollection
HttpFileCollection hfc = Request.Files;
for (int i = 0; i < hfc.Count; i++)
{
HttpPostedFile hpf = hfc[i];
if (hpf.ContentLength > 0)
{
SavePath = ConfigurationManager.AppSettings["PatientPhotoImages"].ToString()
+ GetUniqueKey() + GetFileExtension(hpf.FileName);
hpf.SaveAs(Server.MapPath(SavePath));
//SavePath can be saved in DB.
Msg += GetFileName(hpf.FileName.ToString()) + " , ";
}
}
lblMsg.Text = Msg + " Uploaded Successfully.";
}
}
Step 4: Write the private function which helps to Upload files.
This function helps to extract file extension from the fileName.
private string GetFileExtension(string FileName)
{
char saperator = ‘.’;
string[] temp = FileName.Split(saperator);
return "." + temp[1].ToString();
}
This function helps to get Unique Key, which is used to save files on server with different name that does not collied with each other.
private string GetUniqueKey()
{
int maxSize = 8;
char[] chars = new char[62];
string a;
a = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
chars = a.ToCharArray();
int size = maxSize;
byte[] data = new byte[1];
RNGCryptoServiceProvider crypto = new RNGCryptoServiceProvider();
crypto.GetNonZeroBytes(data);
size = maxSize;
data = new byte[size];
crypto.GetNonZeroBytes(data);
StringBuilder result = new StringBuilder(size);
foreach (byte b in data)
{
result.Append(chars[b % (chars.Length - 1)]);
}
return result.ToString();
}
This function help to get Filename from the filepath.
private string GetFileName(string filePath)
{
FileInfo fi = new FileInfo(filePath);
return fi.Name;
}
Step 5: Add Server Side Validation Code
This is the function which is used to validate files that user wants to upload. If the client side validation does not work, this code will help us to identify the invalid files.
Validation rules like whether file type is correct or not, file size is valid or not.
If you do not want to validate the files on server side, you can ignore this code. But I prefer to use it.
private bool ServerSideValidation()
{
string errorMsg = string.Empty , temp=null;
bool errorFlag = true;
// Get the HttpFileCollection
HttpFileCollection hfc = Request.Files;
for (int i = 0; i < hfc.Count; i++)
{
HttpPostedFile hpf = hfc[i];
if (hpf.ContentLength > 0)
{
temp = ValidateImage(hpf);
if(temp != null)
{
errorMsg += GetFileName(hpf.FileName.ToString()) + " has error : " + temp;
temp = null;
}
}
}
if (errorMsg != "")
{
lblMsg.Text = errorMsg;
errorFlag = false;
}
return errorFlag;
}
This function used to check file type & file size. If file is invalid than it will return error message.
private string ValidateImage(HttpPostedFile myFile)
{
string msg = null;
int FileMaxSize = Convert.ToInt32(ConfigurationManager.AppSettings["FileUploadSizeLimit"].ToString());
//Check Length of File is Valid or Not.
if (myFile.ContentLength > FileMaxSize)
{
msg = msg + "File Size is Too Large.";
}
//Check File Type is Valid or Not.
if (!IsValidFile(myFile.FileName))
{
msg = msg + "Invalid File Type.";
}
return msg;
}
This function is used to check whether the file that user want to upload is valid file type or not.
private bool IsValidFile(string filePath)
{
bool isValid = false;
string[] fileExtensions = { ".bmp", ".jpg", ".png", ".gif", ".jpeg", ".BMP", ".JPG", ".PNG", ".GIF", ".JPEG" };
for (int i = 0; i < fileExtensions.Length; i++)
{
if (filePath.Contains(fileExtensions[i]))
{
isValid = true;
}
}
return isValid;
}
Conclusion:
This code is complete solution that helps to upload multiple file using File Upload with jQuery plugin. I was always in a need of such code in my route work so I decided to write the code that helps others also.
Hope this will help !!!
Jay Ganesh
