asp.net - Object reference not set to an instance of an object -

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• what nullreferenceexception, , how fix it? 32 answers

i new asp.net mvc , cannot find solution how make selectable dropdown list.

my model:

public class parentcategory {      public int id { get; set; }     [required]     [display(name = "parent category name")]     public string pcatname { get; set; }     [required]     [display(name = "urlseo")]     public string urlseo { get; set; }     [required]     [display(name = "description")]     public string pcatlogo { get; set; }      public icollection<childcategory> childcategories { get; set; }     }      public class addparentcategoryviewmodel     {         public int id { get; set; }         public string pcatname { get; set; }         public string urlseo { get; set; }         public string pcatlogo { get; set; }     } 

my controller

    [httpget]     public actionresult addnewpcat()     {         list<int> numlist = new list<int>();         int num = 0;         var newid = num;         addparentcategoryviewmodel model = new addparentcategoryviewmodel();         model.id = newid;         return view(model);     }      [httppost]     [validateantiforgerytoken]     [validateinput(false)]     public actionresult addnewpcat([bind(include = "id,pcatname,urlseo,pcatlogo")]addparentcategoryviewmodel model, httppostedfilebase file)     {              var filename = path.getfilename(file.filename);                       var path = path.combine(server.mappath("~/image/pcatlogo/"), filename);             file.saveas(path);             model.pcatlogo = file.filename;          var pcategory = new parentcategory         {             id = model.id,             pcatname = model.pcatname,             urlseo = model.urlseo,             pcatlogo = model.pcatlogo          };          _pagerepository.addnewparentcategory(pcategory);         return redirecttoaction("index", "page");     } 

my repository is:

    public void addnewparentcategory(parentcategory pcategory)     {         _context.parentcategories.add(pcategory);         save();     } 

and view:

@model bandymas.models.pageviewmodels.addparentcategoryviewmodel @using bandymas.controllers; @{ viewbag.title = "add new pcat"; layout = "~/views/shared/_layout.cshtml"; } @section scripts { <script src="~/scripts/view.js"></script> <script src="~/ckeditor/ckeditor.js"></script> }  @using (html.beginform("addnewpcat", "page", null, formmethod.post, new { role = "form" }))    {    @html.antiforgerytoken()     <div class="editpostcontainer">     <table>         @*<tr>                 <td>id :</td>                 <td colspan="2" class="editpageid">@html.textboxfor(m => m.id, new { @class = "editidinp", @readonly = "readonly" })</td>             </tr>*@         <tr>             <td>pcatname :</td>             <td colspan="2" class="editpageusername">@html.textboxfor(m => m.pcatname, new { @class = "editpcatnameinp" })</td>         </tr>         <tr>             <td>urlseo :</td>             <td colspan="2">@html.textboxfor(m => m.urlseo, new { @class = "editurlseo" })</td>         </tr>         <tr>             <td>pcatlogo :</td>             @*<td colspan="2">@html.textboxfor(m => m.pcatlogo, new { @class = "editpcatlogo" })</td>*@             <td>                 <input id="imagepath" title="upload category image"                        type="file" name="file" />             </td>         </tr>         <tr>         <td></td>         <td colspan="3" class="editpagebody"><input class="comtextbtn" type="submit" value="&#x27a5;" /></td>     </tr>     </table>    </div>    } 

something wrong file upload. problem is:

an exception of type 'system.nullreferenceexception' occurred in bandymas.dll not handled in user code additional information: object reference not set instance of object.

it first time face problem , cannot find solution anywhere... thank in advance.

you need add enctype="multipart/form-data" form post file like

html.beginform(     action, controller, formmethod.post, new { enctype="multipart/form-data"})