下载图片asp.netmvc

Question

您好，我有一个按钮，当我单击它时，此函数称为：

public async Task<IActionResult> QrCode(int Id)
        {
            var model = await context.Files.Where(x => x.Id == Id).FirstOrDefaultAsync();
            string qrUrl = CreateQrLink(Id);
            FileDetailsViewModel fileDetails = new FileDetailsViewModel
            {
                Id = model.Id,
                Name = model.Name,
                Author=model.Author,
                Description=model.Description,
                Genre=model.Genre,
                PublishedOn = model.PublishedOn,
                QrUrl = qrUrl
            };
            return View(fileDetails);
          
        }

这里是CreateQrLink函数

  public string CreateQrLink(int Id)
        {
            var baseUrl = string.Format("{0}://{1}{2}",Request.Scheme, Request.Host, Url.Content("~"));
            QRCodeGenerator QrGenerator = new QRCodeGenerator();
            var url = Url.Action("DownloadFileFromFileSystem", "Files", new { id = Id });
         
            QRCodeData QrCodeInfo = QrGenerator.CreateQrCode(baseUrl+url, QRCodeGenerator.ECCLevel.Q);
            QRCode QrCode = new QRCode(QrCodeInfo);
            
            Bitmap QrBitmap = QrCode.GetGraphic(60);
            byte[] BitmapArray;
            using(MemoryStream ms = new MemoryStream())
            {
                QrBitmap.Save(ms, ImageFormat.Png);
                BitmapArray = ms.ToArray();
            }
            string qrUri= string.Format("data:image/png;base64,{0}", Convert.ToBase64String(BitmapArray));
            return qrUri;
        }

这是我想通过点击下载QrCode按钮从这个视图下载图像的视图，我如何实现它？我不在数据库中保存QrLink我应该保存它还是其他什么？我想从src=Model获取照片。QrUrl

@model FileDetailsViewModel
@{ 
    ViewBag.Title = "Qr Code";
}
<div class="row justify-content-center m-3">
    <div class="col-sm-8">
        <div class="card">
            <div class="card-header">
                <h1>@Model.Name</h1>
                <h2>Product Id: @Model.Id</h2>
            </div>
            <div class="card-body text-center">
                <img style="width:450px;height:450px;" src="@Model.QrUrl" />
               
            </div>
            <div class="card-footer text-center">
                <a asp-controller="files" asp-action="Details" asp-route-id="@Model.Id" class="btn btn-primary">Back</a>
                <a href="#" class="btn btn-success">Download QrCode</a>
            </div>
        </div>
    </div>
</div>

Answer 1

下面是一个简单的解决方案add download=“下载文件的名称”href=“图像的url”

<a download="@Model.Name" style="width:150px;" href="@Model.QrUrl"class="btn btn-success">Download</a>

Answer 2

返回类型应为FileResult，如下所示。

string filePath = string.Format("data:image/png;base64,{0}", Convert.ToBase64String(BitmapArray))

string contentType = ImageFormat.Png.ToString();

FileResult qrUri= this.File(filePath, contentType);
return qrUri;