我正在尝试构建一种方法，该方法可将Guid创建并插入到先前保存的媒体文件的数据库中，并将其插入到项目的wwwroot中。我将实体基本上分为三个部分：数据层的EF模型，业务层的服务模型和Web层的ViewModel。
如我所说，文件已保存在Web层的文件夹中，并且我已经成功创建了一种旨在上载和提取压缩文件夹的方法，并将提取的文件馈送到文件夹中经过清理的文件夹结构中wwwroot文件夹。我尝试过的是构建ViewModel并将它们手动映射到EF模型。 VM拥有3个特别称为EF的模型：MediaModel，FolderUpload和Test。
在上载/提取文件夹的方法中，它立即将新的Guid附加到数据库中的文件夹本身，并列出该文件夹的保存位置。就是那个方法。
在我遇到问题的当前方法中，我尝试对媒体文件执行相同的操作，在其上设置布尔“选择”选项，立即为其附加新的GUID，并保存文件夹/文件数据库的位置。当我在其上放置一个断点时，它得到的是空引用。当然，我将添加示例代码来展示正在发生的事情。
来自控制器：
public IActionResult CreateMediaTest([Bind("LocationPath, Selected, MediaID, TestID, FolderName, DataAdded")]CombinedMediaViewModel fm, string path, string Id)
{
try
{
if (ModelState.IsValid)
{
var getTestItem = _service.GetMediaTestByID(Id);
var getMediaItem = _service.GetMediaItem(Id);
var getFolderByID = _service.GetFolderByID(Id);
var getLocationPath = _service.GetLocationPath(path);
MediaModel test = new MediaModel
{
MediaID = getMediaItem.MediaID,
TestID = getTestItem.TestID,
Selected = true,
LocationPath = getLocationPath.ExtractPath,
FolderName = fm.Folder.FolderName,
DateAdded = fm.Media.DateAdded
};
var result = _service.CreateMediaTest(test);
}
TempData[StaticString.StatusMessage] = "Your have successfully created a test!";
return RedirectToAction(nameof(UploadConfirmationPage), new { id = fm.MediaID == Guid.Empty });
}
catch (Exception ex)
{
TempData[StaticString.StatusMessage] = "Error: " + ex.Message;
return RedirectToAction(nameof(ManageCurrentMediaPage), new { id = fm.MediaID == Guid.Empty });
}
}
来自业务层：
public MediaModel GetMediaItem(string ID)
{
return _repo.GetMediaItem(ID);
}
public FolderUpload GetFolderByID(string ID)
{
return _repo.GetFolderByID(ID);
}
public FolderUpload GetLocationPath(string path)
{
return _repo.GetLocationPath(path);
}
这是ViewModel：
public class CombinedMediaViewModel
{
#region Mapped Entity Items
public MediaModel Media { get; set; }
public FolderUpload Folder { get; set; }
public Test Test { get; set; }
public IdentityUser User { get; set; }
#endregion
#region Mapped Frontend Items
public string FolderPath { get; set; }
public string FolderName { get; set; }
public Guid MediaID { get; set; }
public string UserID { get; set; }
public DateTime DateCreated { get; set; }
public Guid TestID { get; set; }
public bool Selected { get; set; }
#endregion
}
这是cshtml视图：
<div class="d-flex justify-content-between align-items-center mb-3">
@if (Model.URL.ToLower() != "/explorer/")
{
<h4 class="card-title mb-0">@Model.FolderName</h4>
<div class="titles">
@await Html.PartialAsync(PartialView.StatusMessage, TempData[StaticString.StatusMessage])
</div>
}
</div>
<div class="card-block">
<ul>
@*Listing the directories *@
@foreach (Crowdsource.DataAccess.Models.FolderUpload dir in Model.FolderList)
{
<li>
<input type="hidden" asp-for="@dir.FolderID" />
<input type="hidden" asp-for="@dir.FolderName" />
<input type="hidden" asp-for="@dir.ExtractPath" />
<img src="~/img/folder.jpg" alt="Folder" align="top" style="width: 20px; height: 20px; border: none" />
<a href="@(Model.URL + dir.FolderName)/" title="@dir.FolderName">@dir.FolderName</a>
. . . . . . @dir.DateAdded
</li>
}
@*Listing the files *@
@*@foreach (Crowdsource.DataAccess.Models.MediaModel item in Model.MediaItem)
{
<li>
<input type="hidden" asp-for="@item.Test.TestName" />
</li>
*@
@foreach (Crowdsource.DataAccess.Models.MediaModel file in Model.MediaList)
{
<li>
<input type="hidden" asp-for="@file.MediaID" />
<input type="hidden" asp-for="@file.FileName" />
<input type="hidden" asp-for="@file.DateAdded" />
<input type="hidden" asp-for="@file.Folder.FolderName" />
<input type="hidden" asp-for="@file.Test.AID" />
<input type="checkbox" asp-for="@file.Selected" class="form-check-input" />
<img src="~/img/image.png" alt="Folder" align="top" style="width: 20px; height: 20px; border: none" />
<a href="@(Model.URL + file.FileName)"
title="@file.FileName" target="_blank">
@file.FileName
</a>. . . . . . @file.FileSizeText
. . . . . . @file.DateAdded
</li>
}
</ul>
<div class="card-footer">
<button type="submit" class="btn btn-inverse-success">Create Test</button>
<button type="submit" class="btn btn-inverse-danger">Delete Folder</button>
</div>
</div>