An unhandled exception occurred while processing the request.
InvalidOperationException: The layout view '~/Areas/Admin/Views/Shared/_Layout' could not be located. The following locations were searched:
~/Areas/Admin/Views/Shared/_Layout
~/Areas/Admin/Views/Shared/_Layout
Microsoft.AspNetCore.Mvc.Razor.RazorView.GetLayoutPage(ViewContext context, string executingFilePath, string layoutPath)
解决方法：
将模板页
@{
Layout = "~/Areas/Admin/Views/Shared/_Layout";
}
改成：
@{
Layout = "~/Areas/Admin/Views/Shared/_Layout.cshtml";
}