[英]System.Reflection.TargetException: 'Non-static method requires a target.' only with VS 2017 not with VS 2013
[英]Why the postman is returning a “Non-static method requires a target.”
我的SavesController(Web Api控制器)中有一个Save方法。 当我与邮递员测试时,它返回了此结果。
{
"message": "An error has occurred.",
"exceptionMessage": "Non-static method requires a target.",
"exceptionType": "System.Reflection.TargetException",
"stackTrace": " at System.Web.Http.ApiController. <InvokeActionWithExceptionFilters>d__1.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()\r\n at System.Web.Http.Dispatcher.HttpControllerDispatcher.<SendAsync>d__0.MoveNext()"
}
我的保存方法是这样。 if语句引发异常
[HttpPost]
public IHttpActionResult Save(SavesDto dto)
{
var userId = User.Identity.GetUserId();
if (_context.SavedPosts.Any(a => a.AttendeeId == userId && a.PostId == dto.PostId))
return BadRequest("The save already exists.");
var savedPost = new Saves
{
PostId = dto.PostId,
AttendeeId = userId
};
_context.SavedPosts.Add(savedPost);
_context.SaveChanges();
return Ok();
}
我已经在互联网上搜索过,发现问题出在LINQ中使用空值。 但是Linq语句中的任何方法仅返回true / false,为什么会抛出此异常?
public class SavesDto
{
public int PostId { get; set; }
}
我在这里叫阿皮
@foreach(var post in Model)
{
<button
data-post-id="@post.Id"
class="btn btn-default btn-sm pull-right .js-toggle-save">Save ?</button
}
@section scripts
{
<script>
$(document).ready(function()
{
$(".js-toggle-save").click(function(e)
{
var button = $(e.target);
$.post("/api/saves", { postId: button.attr("data-post-id") } )
.done(function()
{
button.removeClass("btn-default")
.addClass("btn-info").text("Saved");
})
.fail(function ()
{
alert("something failed");
})
});
}
);
</script>
}
PostId和AttendeeId不可为空
public class Saves
{
public ApplicationUser User { get; set; }
public Post Post { get; set; }
[Key]
[Column(Order = 1)]
public int PostId { get; set; }
[Key]
[Column(Order = 2)]
public string AttendeeId { get; set; }
}
当您在lambda表达式中使用变量为空时,会发生此异常。 看来dto对象为null。 因此,尝试这样做:
if (dto != null && _context.SavedPosts.Any(a => a.AttendeeId == userId
&& a.PostId == dto.PostId))
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