FileUpload control in asp.net throwing exception - asp.net

Question

I am trying to read an Excel sheet using C# which is to be loaded by end user from fileUpload control.
I am writing my code to save the file on server in event handler of another button control(Upload). But when I click on Upload Button I am getting this exception:
The process cannot access the file 'E:\MyProjectName\App_Data\sampledata.xlsx' because it is being used by another process.
Here is the code that I have used in event handler:
string fileName = Path.GetFileName(file_upload.PostedFile.FileName);
string fileExtension = Path.GetExtension(file_upload.PostedFile.FileName);
string fileLocation = Server.MapPath("~/App_Data/" + fileName);
//if (File.Exists(fileLocation))
// File.Delete(fileLocation);
file_upload.SaveAs(fileLocation);
Even deleting the file is not working, throwing the same exception.

Answer 1

Make sure, some other process is not accessing that file.
This error might occurs whenever you are trying to upload file, without explicitly removing it from memory.
So try this:
try
{
string fileName = Path.GetFileName(file_upload.PostedFile.FileName);
string fileExtension = Path.GetExtension(file_upload.PostedFile.FileName);
string fileLocation = Server.MapPath("~/App_Data/" + fileName);
//if (File.Exists(fileLocation))
// File.Delete(fileLocation);
file_upload.SaveAs(fileLocation);
}
catch (Exception ex)
{
throw ex.Message;
}
finally
{
file_upload.PostedFile.InputStream.Flush();
file_upload.PostedFile.InputStream.Close();
file_upload.FileContent.Dispose();
//Release File from Memory after uploading
}

Answer 2

The references are hanging in memory, If you are using Visual Studio try with Clean Solution and Rebuild again, if you are in IIS, just do a recycle of your application.
To avoid this problems try to dispose the files once you used them, something like:
using(var file= new FileInfo(path))
{
//use the file
//it will be automatically disposed after use
}

Answer 3

If i have understood the scenario properly.
For Upload control, I don't think you have to write code for Upload Button. When you click on your button,your upload control has locked the file and using it so it is already used by one process. Code written for button will be another process.
Prior to this, check whether your file is not opened anywhere and pending for edit.