在产品页面上使用ASP.NET上的Sixlabour.ImageSharper Core mvc

Question

在我的项目产品页面控制器中，我想上传一个图像，并在提交后自动压缩图像，因此我使用Sixlabour.ImageSharper。它在我的演示项目中起作用(我只添加了一个输入字段图像(。当我在我的主要项目中转移这个代码时，它不起作用。

这是我的代码：

ProductController.cs

public string ResizeImage(Image img, int maxWidth, int maxHeight)
{
if (img.Width > maxWidth || img.Height > maxHeight)
{
double widthRatio = (double)img.Width / (double)maxWidth;
double heightRatio = (double)img.Height / (double)maxHeight;
double ratio = Math.Max(widthRatio, heightRatio);
int newWidth = (int)(img.Width / ratio);
int newHeight = (int)(img.Height / ratio);
return newHeight.ToString() + "," + newWidth.ToString();
}
else
{
return img.Height.ToString() + "," + img.Width.ToString();
}
}
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<IActionResult> Upsert(ProductVM productVM,IFormFile file)
{
if (ModelState.IsValid)
{
string webRootPath = _hostEnvironment.WebRootPath;
var files = HttpContext.Request.Form.Files;
if (files.Count > 0)
{
string fileName = Guid.NewGuid().ToString();
var uploads = Path.Combine(webRootPath, @"imagesproducts");
var extension = Path.GetExtension(files[0].FileName);

using (var image = Image.Load(file.OpenReadStream()))
{
string newSize = ResizeImage(image, 500, 500);
string[] aSize = newSize.Split(',');
image.Mutate(h => h.Resize(Convert.ToInt32(aSize[1]), Convert.ToInt32(aSize[0])));
}

if (productVM.Product.ImageUrl != null)
{
//this is an edit and we need to remove old image
var imagePath = Path.Combine(webRootPath, productVM.Product.ImageUrl.TrimStart('\'));
if (System.IO.File.Exists(imagePath))
{
System.IO.File.Delete(imagePath);
}
}
using(var filesStreams = new FileStream(Path.Combine(uploads, fileName + extension), FileMode.Create))
{
files[0].CopyTo(filesStreams);
}
productVM.Product.ImageUrl = @"imagesproducts" + fileName + extension;
}
else
{
//update when they do not change the image
if(productVM.Product.Id != 0)
{
Product objFromDb = _unitOfWork.Product.Get(productVM.Product.Id);
productVM.Product.ImageUrl = objFromDb.ImageUrl;
}
}

if (productVM.Product.Id == 0)
{
_unitOfWork.Product.Add(productVM.Product);
}
else
{
_unitOfWork.Product.Update(productVM.Product);
}
_unitOfWork.Save();
return RedirectToAction(nameof(Index));
}

return View(productVM);
}

I used webrootpath for uploading images.how can I solve this
**Error** show "Object reference not set to an instance of an object" on using (var image = Image.Load(file.OpenReadStream()))

Answer 1

我自己解决了这是解决方案。。我删除webRoot路径，并手动调用它

[HttpPost]
[ValidateAntiForgeryToken]
public async Task<IActionResult> Upsert(ProductVM productVM, IFormFile file)
{
if (ModelState.IsValid)
{
var files = HttpContext.Request.Form.Files;
if (files.Count > 0)
{
string fileName = string.Empty;
string path = string.Empty;
if (file.Length > 0) //that means file was uploaded
{
fileName = Guid.NewGuid() + Path.GetExtension(file.FileName);
path = Path.GetFullPath(Path.Combine(Directory.GetCurrentDirectory(), "wwwroot/images/products"));
string fullPath = Path.Combine(path, fileName);
using (var image = Image.Load(file.OpenReadStream()))
{
string newSize = ResizeImage(image, 500, 500);
string[] aSize = newSize.Split(',');
image.Mutate(h => h.Resize(Convert.ToInt32(aSize[1]), Convert.ToInt32(aSize[0])));
image.Save(fullPath);
}
if(productVM.Product.Id != 0 )
{
Product objFromDb = await _unitOfWork.Product.GetAsync(productVM.Product.Id);
productVM.Product.ImageUrl = objFromDb.ImageUrl;
if(objFromDb.ImageUrl!= null)
{
//Image already exists we need to remove old image
var imagepath = Path.Combine(Directory.GetCurrentDirectory(), objFromDb.ImageUrl.TrimStart('\'));
if (System.IO.File.Exists(imagepath))
System.IO.File.Delete(imagepath);
}
}
productVM.Product.ImageUrl = @"imagesproducts" + fileName;
}
}
else
{
//update when they do not change the image
if (productVM.Product.Id != 0)
{
Product objFromDb = await _unitOfWork.Product.GetAsync(productVM.Product.Id);
productVM.Product.ImageUrl = objFromDb.ImageUrl;
}
}

if (productVM.Product.Id == 0)
{
await _unitOfWork.Product.AddAsync(productVM.Product);
}
else
{
_unitOfWork.Product.Update(productVM.Product);
}
_unitOfWork.Save();
return RedirectToAction(nameof(Index));


}
return View(productVM);
}
public string ResizeImage(Image img, int maxWidth, int maxHeight)
{
if (img.Width > maxWidth || img.Height > maxHeight)
{
double widthRatio = (double)img.Width / (double)maxWidth;
double heightRatio = (double)img.Height / (double)maxHeight;
double ratio = Math.Max(widthRatio, heightRatio);
int newWidth = (int)(img.Width / ratio);
int newHeight = (int)(img.Height / ratio);
return newHeight.ToString() + "," + newWidth.ToString();
}
else
{
return img.Height.ToString() + "," + img.Width.ToString();
}
}