Atmo的程序人生

提示

InvalidOperationException: The view ‘Index’ was not found. The following locations were searched:
/Views/Home/Index.cshtml
/Views/Shared/Index.cshtml

解决方法：

现在的vs2022不知道为什么，选择mvc后，不添加相关mvc的nuget包，或者升级.net版本的时候会遇到这种情况，找不到视图，但是明明试图是存在了，两步：
1、安装Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation包。

2、将program.cs里面的services.AddControllersWithViews();改成services.AddControllersWithViews().AddRazorRuntimeCompilation();

3 、完成以上两步基本调试的时候不报错了，但是可能发布后会报错，还是一样的错误提示，这时候要看下vs2022的版本了，vs2022 17.7.7 要更新一下，更新成vs2022.17.8.0就可以解决掉了，总之17.7.7还有其他莫名的错误，能升级升级。

var yearList = _context.Content.Where(a => (a.CategoryId == cid )).ToList();
            var query = from t in list
                        group t by new
                        {
                            year = new { t.UpdateTime.Year }
                        }
                        into g
                        select new {
                            year = g.Key.year
            };

<select class="form-control" asp-for="State" asp-items="@Html.GetEnumSelectList(typeof(FF.Models.Enum.OrderState))"></select>

可以遍历枚举，还可以有默认值

HttpResponseMessage result = new HttpResponseMessage(HttpStatusCode.OK);
result.Content = new ByteArrayContent(ms.ToArray());
result.Content.Headers.ContentType = new MediaTypeHeaderValue("image/png");
return result ; 

网上的代码基本上都是这样的 但是api的请求结果是Json

{"Version":{"Major":1,"Minor":1,"Build":-1,"Revision":-1,"MajorRevision":-1,"MinorRevision":-1},"Content":{"Headers":[{"Key":"Content-Type","Value":["image/jpg"]}]},"StatusCode":200,"ReasonPhrase":"OK","Headers":[],"RequestMessage":null,"IsSuccessStatusCode":true}

最终结果，输入图片 使用IAcitonResult ，返回子类FileContentResult，直接输出图片

public IActionResult GetQr(string str)
{
    var img = LIB.QR.GetQrCode(str);
    MemoryStream ms = new MemoryStream();
    img.Save(ms, System.Drawing.Imaging.ImageFormat.Png);
    return new FileContentResult(ms.ToArray(), "image/png");
}