[英]Convert IFormFile to Image in Asp Core
如果文件是图像,我需要调整文件上传的大小。
我写扩展的大小:
public static Image ResizeImage(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;
}
这是上Upload Action :
[HttpPost("UploadNewsPic"), DisableRequestSizeLimit]
public IActionResult UploadNewsPic(IFormFile file)
{
if (file.IsImage())
{
}
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))
{
file.CopyTo(stream);
}
}
return Ok();
}
catch (Exception e)
{
return BadRequest();
}
}
现在我的问题在这里=>我的扩展仅适用于Image
文件的类型,但是此文件的类型为IFormFile
。 如何将IFormFile
转换为Image
类型?
您应该使用Image.FromStream()
方法将流作为Image读取:
public async Task<IActionResult> FileUpload(IFormFile file)
{
if (file == null || file.Length == 0)
{
return BadRequest();
}
using (var memoryStream = new MemoryStream())
{
await file.CopyToAsync(memoryStream);
using (var img = Image.FromStream(memoryStream))
{
// TODO: ResizeImage(img, 100, 100);
}
}
}
您需要使用OpenReadStream打开文件并将其转换为图像格式。 并将其传递给您的扩展方法。
FileDetails fileDetails;
using (var reader = new StreamReader(file.OpenReadStream()))
{
var fileContent = reader.ReadToEnd();
var parsedContentDisposition = ContentDispositionHeaderValue.Parse(file.ContentDisposition);
fileDetails = new FileDetails
{
Filename = parsedContentDisposition.FileName,
Content = fileContent,
ContentType=file.ContentType
};
}
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