I am trying to create a thumbnail image in asp.net-core 2.2 application but I keep getting the above error whenever it gets to the point of creating the thumbnail.
The main image creates and stores fine but it is not able to create the thumbnail. Please I will appreciate any guide to resolve the error
Here are my methods for storing the uploaded image. This one works as expected
using LazZiya.ImageResize;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using System;
using System.Collections.Generic;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
namespace eSchool.Models.Utilities
{
public class FileUploadHelper
{
private readonly IHostingEnvironment host;
public FileUploadHelper(IHostingEnvironment _host)
{
host = _host;
}
public async Task<string> SaveFileAsync(IFormFile file, string pathToUplaod)
{
string webroot=host.WebRootPath;
string DesiredDirectoryLocation = Path.Combine(webroot,pathToUplaod);
if(!Directory.Exists(DesiredDirectoryLocation))
{
Directory.CreateDirectory(DesiredDirectoryLocation);
}
string imageUrl = string.Empty;
var filename = Path.GetRandomFileName();
var newfilename = CreateUniqueFileName(file);
string pathwithfileName = DesiredDirectoryLocation + "/" + newfilename;
using (var fileStream = new FileStream(pathwithfileName, FileMode.Create))
{
await file.CopyToAsync(fileStream);
}
imageUrl = newfilename;
return imageUrl;
}
I have tried two different methods to create the thumbnail but either of them gives the above error
Here are the two methods.
The first one is this:
public string CreateThumbImage(IFormFile uploadedFile, string desiredThumbPath,string desiredThumbFilename, int desiredThumbWidth, int desiredThumbHeight)
{
try
{
Stream filestream = uploadedFile.OpenReadStream();
Image thumbnailStream = Image.FromStream(filestream);
Image thumbnailImage = thumbnailStream.GetThumbnailImage(desiredThumbWidth, desiredThumbHeight, () => false, IntPtr.Zero);
string webroot = host.WebRootPath;
string DesiredDirectoryLocation = Path.Combine(webroot, desiredThumbPath);
if (!Directory.Exists(DesiredDirectoryLocation))
{
Directory.CreateDirectory(DesiredDirectoryLocation);
}
string thumbFullPathName = desiredThumbPath + "/" + desiredThumbFilename;
thumbnailImage.Save(thumbFullPathName);
return thumbFullPathName;
}
catch
{
throw;
}
}
And the second one is this:
public void ResizeImage(IFormFile uploadedFile, string desiredThumbPath, int desiredWidth=0, int desiredHeight=0)
{
if (uploadedFile.Length > 0)
{
using (var stream = uploadedFile.OpenReadStream())
{
var uploadedImage = System.Drawing.Image.FromStream(stream);
//decide how to scale dimensions
if (desiredHeight == 0 && desiredWidth > 0)
{
var img = ImageResize.ScaleByWidth(uploadedImage, desiredWidth); // returns System.Drawing.Image file
img.SaveAs(desiredThumbPath);
}
else if(desiredWidth == 0 && desiredHeight > 0)
{
var img = ImageResize.ScaleByHeight(uploadedImage, desiredHeight); // returns System.Drawing.Image file
img.SaveAs(desiredThumbPath);
}
else
{
var img = ImageResize.Scale(uploadedImage, desiredWidth,desiredHeight); // returns System.Drawing.Image file
img.SaveAs(desiredThumbPath);
}
}
}
return;
}
And this is where I call the methods:
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<ActionResult> Register(RegisterViewModel model)
{
FileUploadHelper uploadHelper = new FileUploadHelper(_host);
if (EmailValidation.EmailExists(model.EmailAddress,_context))
{
ModelState.AddModelError("EmailAddress", "This email address is already registered with us.");
}
if (model.Photo != null)
{
string[] extensions = new string[] { ".jpeg",".jpg", ".gif", ".png" };
///Validate the type of the image file being uploaded
ResponseMsg fileTypeValidated = uploadHelper.ValidateFileExtension(model.Photo, extensions);
if (!fileTypeValidated.ResponseStatus)
{
ModelState.AddModelError("Photo", fileTypeValidated.ResponseDescription);
}
///Validate the size of the image file being uploaded
ResponseMsg fileSizeValidated = uploadHelper.ValidateFilesize(model.Photo, 1);
if (!fileSizeValidated.ResponseStatus)
{
ModelState.AddModelError("Photo", fileSizeValidated.ResponseDescription);
}
}
if (ModelState.IsValid)
{
try
{
Instructor instructor = new Instructor
{
Surname = model.Surname,
OtherNames = model.Othernames,
Email = model.EmailAddress,
UserName = model.EmailAddress,
PhoneNumber = model.PhoneNumber,
Gender = model.Gender,
StateId = model.ResidenceState,
LgaId = model.ResidenceLga,
DateOfBirth = model.DateOfBirth,
TimeRegistered = DateTime.Now
};
var photo = await uploadHelper.SaveFileAsync(model.Photo,"images/instructors");
//Create image thumbnail for the instructor photo
var photo_thumbnail = "images/instructors/thumbs/" + photo;
uploadHelper.CreateThumbImage(model.Photo, "images/instructors/thumbs/", photo, 100, 100);...
Please help me if you can point out where I am missing the right path or a better way to handle image thumbnail creation in ASP.NET-Core 2.* to fix the error.
Regards
