Question

在用户选择要上传的照片时，我需要更改照片的大小并将其保存为新的大小。

i使用此代码，但未保存为新大小。有什么问题？

public async Task<IActionResult> UploadNewsPic()
    {
        var file = Request.Form.Files[0];
        try
        {
            if (file.Length > 0)
            {
                string fileName = ContentDispositionHeaderValue.Parse(file.ContentDisposition).FileName.Trim('"');
                string fullPath = Path.Combine(_applicationRoot.UploadNewPath(), file.Name);
                using (var stream = new FileStream(fullPath, FileMode.Create))
                {
                    if (file.IsImage())
                    {
                        await file.ResizeImage(3, 3);
                        file.CopyTo(stream);
                    }
                }
            }
            return Ok();
        }
        catch (Exception e)
        {
            return BadRequest();
        }
    }

这是调整大小范围：

 public async static Task<Image> ResizeImage(this IFormFile file, int width, int height)
    {
        using (var memoryStream = new MemoryStream())
        {
            await file.CopyToAsync(memoryStream);
            using (var img = Image.FromStream(memoryStream))
            {
                return img.Resize(width, height);
            }
        }
    }

    public static Image Resize(this Image image, int width, int height)
    {
        var res = new Bitmap(width, height);
        using (var graphic = Graphics.FromImage(res))
        {
            graphic.InterpolationMode = InterpolationMode.HighQualityBicubic;
            graphic.SmoothingMode = SmoothingMode.HighQuality;
            graphic.PixelOffsetMode = PixelOffsetMode.HighQuality;
            graphic.CompositingQuality = CompositingQuality.HighQuality;
            graphic.DrawImage(image, 0, 0, width, height);
        }
        return res;
    }

Answer 1

您的ResizeImage()函数将返回一个已调整大小的图像，它不会编辑图像本身，因此必须将其设置为变量。

if (file.IsImage())
{
    Image imageResized = await file.ResizeImage(3, 3);
    // ...
}

Answer 2

您需要将let fetchRequest = NSFetchRequest<Project>(entityName: "Project") let sortDescriptor = NSSortDescriptor(key: "pname", ascending: true) fetchRequest.sortDescriptors = [sortDescriptor] do { let newProjectArray = try managedContext.fetch(fetchRequest) }catch let error as NSError { print("Could not fetch. \(error), \(error.userInfo)") }中的结果保存到流中。现在，您只是在复制原始文件。

func numberOfSections(in tableView: UITableView) -> Int {
    return (newProjectArray != nil) ? newProjectArray!.count : 0
}

func tableView(_ tableView: UITableView, numberOfRowsInSection
    section: Int) -> Int {
    if newProjectArray![section].isExpandable, let folders =  newProjectArray![section].folders { 
        return folders.count
    } 
    else{
        return 0
    }
}

func tableView(_ tableView: UITableView, heightForHeaderInSection
    section: Int) -> CGFloat {
    return 40
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath:
    IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier:
        "FoldersCell") as! FoldersCell
    if  newProjectArray![indexPath.section].isExpandable == true {
        if let folders = newProjectArray![indexPath.section].folders {
            folder = folders[indexPath.row]
            cell.projectNameLabel.text = folder.name
        }
    }
    return cell
}

在Asp Core中上传时调整图像大小

2 个答案: