本文讲述了c# – 关于MVC 4视图中ViewData的Foreach！具有很好的参考价值，希望对大家有所帮助。一起跟随六星小编过来看看吧，具体如下:

我遇到的问题是我从我的数据库返回一张照片记录,这在我的详细信息视图中工作正常.但是在控制器下的细节我也正在编译一个列表对象,我想在我的详细信息视图中显示它,因为它包含相关的其他照片.因此,在视图的底部,它应列出每个引用的照片名称.我正在使用galleria.Io照片查看器,我想将其插入其中.

当我尝试遍历列表中的每个项目时,我得到：

1. {"Object reference not set to an instance of an object."}

PhotosController

1. publicActionResultDetails(intID=0)
2. {
3. Photos photos = db.FindPhotoByID(ID);
4. if(photos ==null)
5. {
6. returnhttpNotFound();
7. }
8.  
9. List<Photos> photoList=GetimagesFromFilmID(8);
10.  
11. VIEwData["NumberOfImages"]= photoList.Count().ToString();
12. VIEwData["PhotoList"]= photoList;
13.  
14. returnVIEw(photos);
15. }
16.  
17. publicList<Photos>GetimagesFromFilmID(int filmID=8)
18. {
19.  
20. List<Photos> photos;
21.  
22. photos =(from p in db.Photos
23. where p.PhotoDescription=="8"
24. select p).Take(filmID).ToList();
25.  
26. return photos;
27. }

细节视图

1. @modelTestingMVCQA.Models.Photos
2. @*@modelIEnumerable<TestingMVCQA.Models.Photos>*@
3. @{
4. VIEwBag.Title="Details";
5. }
6.  
7. <h2>Details</h2>
8.  
9. <fIEldset>
10. <legend>Photos</legend>
11.  
12. <divclass="display-label">
13. @HTML.displaynameFor(model => model.Photoname)
14. </div>
15. <divclass="display-fIEld">
16. @HTML.displayFor(model => model.Photoname)
17. </div>
18.  
19. <divclass="display-label">
20. @HTML.displaynameFor(model => model.PhotoDescription)
21. </div>
22. <divclass="display-fIEld">
23. @HTML.displayFor(model => model.PhotoDescription)
24. </div>
25.  
26. <divclass="display-label">
27. @HTML.displaynameFor(model => model.Photofilename)
28. </div>
29. <divclass="display-fIEld">
30. @HTML.displayFor(model => model.Photofilename)
31. </div>
32.  
33. <divclass="display-label">
34. @HTML.displaynameFor(model => model.ImageMimeType)
35. </div>
36. <divclass="display-fIEld">
37. @HTML.displayFor(model => model.ImageMimeType)
38. </div>
39.  
40. <script src="@Url.Content("~/Scripts/jquery-1.7.1.Js")"></script>
41. <script src="@Url.Content("~/Scripts/galleria-1.3.6.Js")"></script>
42.  
43. <style>
44. .galleria{ wIDth:900px; height:500px; background:#000 }
45. </style>
46.  
47. @if(Model.Photofile!=null){
48. <divclass="galleria">
49. <img src="@Url.Action("Getimage","Photos",new { ID = Model.PhotoID })" data-Title="My Title" data-description="My description"/>
50. <img src="@Url.Action("Getimage",new { ID = 5 })"/>
51. <img src="@Url.Action("Getimage",new { ID = 6 })"/>
52. <img src="@Url.Action("Getimage",new { ID = 7 })"/>
53. <img src="@Url.Action("Getimage",new { ID = 8 })"/>
54. <img src="@Url.Action("Getimage",new { ID = 9 })"/>
55. <img src="@Url.Action("Getimage",new { ID = 10 })"/>
56. <img src="@Url.Action("Getimage",new { ID = 11 })"/>
57. <img src="@Url.Action("Getimage",new { ID = 12 })"/>
58. <img src="@Url.Action("Getimage",new { ID = 13 })"/>
59. <img src="@Url.Action("Getimage",new { ID = 14 })"/>
60. </div>
61. }
62.  
63. <script>
64. galleria.loadtheme(src ="@Url.Content("~/Scripts/galleria.classic.Js")");
65. galleria.run('.galleria');
66. </script>
67.  
68. </fIEldset>
69.  
70. <p>Your favorite fruit is:</p>@VIEwData["NumberOfImages"]
71. <p>
72. @foreach(var item inVIEwData["NumberOfImages"]asIEnumerable<TestingMVCQA.Models.Photos>)
73. {
74. }
75. </p>
76.  
77. <p>
78. @HTML.Actionlink("Edit","Edit",new{ID=Model.PhotoID})|
79. @HTML.Actionlink("Back to List","Index")
80. </p>

在索引视图中,我有：

1. @modelIEnumerable<TestingMVCQA.Models.Photos>

这允许我使用foreach并且我理解为什么但是当我在详细信息视图中返回单个对象时,我对如何解决问题有点困惑.因此,当它全部工作时,我可以替换Getimage调用和foreach图像本身.

如果您需要任何其他代码或解释,请告诉我们.

您在foreach循环中使用VIEwData [“NumberOfImages”]这是错误的.

你的foreach循环应如下所示： –

1. @foreach(var item inVIEwData["PhotoList"]asIEnumerable<TestingMVCQA.Models.Photos>)
2. {
3. //@item.filename //instead .filename use property which you have used in your model class
4. }