c# - Entity Framework Eager Loading - pass data to ViewModel -

in asp.net mvc core app, action method shown below, i'm passing blogs data , related data posts table view return view(await _context.blogs.include(p => p.posts).tolistasync()); since i'm passing data 2 tables, need use viewmodel shown below. question: how can use viewmodel pass related data controller action method test() view shown below?

in code below i'm getting obvious error:

invalidoperationexception: model item passed viewdatadictionary of type 'system.collections.generic.list'1[asp_core_blogs.models.blog]', viewdatadictionary instance requires model item of type 'system.collections.generic.ilist'1[asp_core_blogs.models.blogpostviewmodels.blogswithrelatedpostsviewmodel]'.

model:

public class bloggingcontext : dbcontext {     public bloggingcontext(dbcontextoptions<bloggingcontext> options)         : base(options)     { }      public dbset<blog> blogs { get; set; }     public dbset<post> posts { get; set; } }  public class blog {     public int blogid { get; set; }     public string url { get; set; }      public list<post> posts { get; set; } }  public class post {     public int postid { get; set; }     public string title { get; set; }     public string content { get; set; }     public int postyear { get; set; }     public int blogid { get; set; }     public blog blog { get; set; } } 

controller:

[httpget] public async task<iactionresult> test(string returnurl = null) {     viewdata["returnurl"] = returnurl;     return view(await _context.blogs.include(p => p.posts).tolistasync()); } 

viewmodel:

public class blogswithrelatedpostsviewmodel {     public int blogid { get; set; }     public int postid { get; set; }     public string url { get; set; }     public string title { get; set; }     public string content { get; set; }     public int postyear { get; set; } } 

view:

@model ilist<asp_core_blogs.models.blogpostviewmodels.blogswithrelatedpostsviewmodel>  <div class="row">     <div class="col-md-12">         <form asp-controller="dbrelated" asp-action="entergrantnumbers" asp-route-returnurl="@viewdata["returnurl"]" method="post">             <table class="table">                 <thead>                     <tr>                         <th></th>                         <th></th>                         <th>url</th>                         <th>title</th>                         <th>content</th>                     </tr>                 </thead>                 <tbody>                     @for (int t = 0; t < model.count; t++)                     {                         <tr>                             <td><input type="hidden" asp-for="@model[t].blogid" /></td>                             <td><input type="hidden" asp-for="@model[t].postid" /></td>                             <td>                                 <input type="text" asp-for="@model[t].url" style="border:0;" readonly /> <!--not using /*html.displayfor(modelitem => model[t].url)*/ since not submit statename on post. not using <label asp-for=.....> since bootstrap bold text of <label> tag-->                             </td>                             <td>                                 <input asp-for="@model[t].title" />                             </td>                             <td>                                 <input asp-for="@model[t].content" />                             </td>                         </tr>                     }                 </tbody>             </table>             <button type="submit" class="btn btn-default">save</button>         </form>     </div> </div> 

you need project query using blogswithrelatedpostsviewmodel class:

     return view( _context.blogs                           .include(p => p.posts)                           .selectmany(e=> e.posts.select(p=> new blogswithrelatedpostsviewmodel                                                              {                                                               blogid= e.blogid,                                                               postid=p.postid,                                                               url=e.url,                                                               ...                                                              })                           .tolist());  

selectmany extension method allows flatten each projection e.posts 1 sequence, @ end list<blogswithrelatedpostsviewmodel>