How to close file stream in .netcore - asp.net-core

Question

I am new to .net core and c#. I have a file upload requirement in my project. I am trying to upload my file to aws s3. I upload file from a folder in my project root folder and then delete the uploaded file from there. But when I try to upload to s3 I am getting following error
The process cannot access the file because it is being used by another process.
Here is my code to upload file
string fileFolder = Path.Combine(hostingEnvironment.WebRootPath, "TempFiles");
uniqueFileName1 = Guid.NewGuid().ToString() + "_" + cm.UDocument1.FileName;
string filePath = Path.Combine(fileFolder, uniqueFileName1);
cm.UDocument1.CopyTo(new FileStream(filePath, FileMode.Create));
var tempPath = Path.Combine(hostingEnvironment.WebRootPath, "TempFiles", Path.GetFileName(uniqueFileName1));
UploadFile(cm.UDocument1,tempPath);
[HttpPost]
public ActionResult UploadFile(IFormFile file,string path)
{
var s3Client = new AmazonS3Client(accesskey, secretkey, bucketRegion);
var fileTransferUtility = new TransferUtility(s3Client);
try
{
if (file.Length > 0)
{
var fileTransferUtilityRequest = new TransferUtilityUploadRequest
{
BucketName = bucketName,
FilePath = path,
StorageClass = S3StorageClass.Standard,
Key = file.FileName
};
fileTransferUtilityRequest.Metadata.Add("param1", "Value1");
fileTransferUtilityRequest.Metadata.Add("param2", "Value2");
fileTransferUtility.Upload(fileTransferUtilityRequest);
fileTransferUtility.Dispose();
string[] tmp = { "" };
tmp = fileName.Split("-");
}
ViewBag.Message = "File Uploaded Successfully!!";
if (System.IO.File.Exists(path))
{
System.IO.File.Delete(path);
}
}
return ViewBag.Message;
}
what can I do about it?

Answer 1

On this line:
cm.UDocument1.CopyTo(new FileStream(filePath, FileMode.Create));
You create a file stream but you dont dispose it.
wrap in a using statement instead:
using (var iNeedToLearnAboutDispose = new FileStream(filePath, FileMode.Create))
{
cm.UDocument1.CopyTo(iNeedToLearnAboutDispose);
}