c# - WPF: Can't access the view. Datagrid is not refreshing with data in tabs -

i'm following how create tab-able content in wpf/c#? want each tab show datagrid. datagrid doesn't show , doesn't show data. when step code, see 0,1 being set.

mainwindow.xaml

<window x:class="mvvmdatainstances.mainwindow"         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:viewmodel="clr-namespace:mvvmdatainstances"         title="mainwindow" height="350" width="525">      <window.datacontext>         <viewmodel:mainwindowviewmodel />     </window.datacontext>     <grid>         <grid.resources>             <datatemplate x:key="contenttemplate"                        datatype="{x:type viewmodel:childviewmodel}"/>         </grid.resources>         <tabcontrol contenttemplate="{staticresource contenttemplate}"                   itemssource="{binding items}" />     </grid> </window> 

mainwindowviewmodel.cs

 public observablecollection<childviewmodel> items { get; private set; }          public mainwindowviewmodel()         {              items = new observablecollection<childviewmodel> {new childviewmodel(0), new childviewmodel(1)};         } 

childview.xaml

<usercontrol x:class="mvvmdatainstances.view"              xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"              xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"               xmlns:d="http://schemas.microsoft.com/expression/blend/2008"              xmlns:viewmodel="clr-namespace:mvvmdatainstances"              mc:ignorable="d"               d:designheight="300" d:designwidth="300">     <usercontrol.datacontext>         <viewmodel:childviewmodel/>     </usercontrol.datacontext>             <datagrid horizontalalignment="stretch" verticalalignment="stretch" itemssource="{binding grid, mode=twoway}" />  </usercontrol> 

childviewmodel.cs

public class childviewmodel : viewmodelbase     {         private observablecollection<childmodel> _grid;          public observablecollection<childmodel> grid         {             { return _grid; }             private set             {                 _grid = value;                 onpropertychanged("grid");             }         }          public childmodel data { get; set; }          public childviewmodel()         {         }          public childviewmodel(int tabnumber)         {             data = new childmodel {a = tabnumber.tostring(cultureinfo.invariantculture)};              grid = new observablecollection<childmodel> {data};         }     } 

childmodel.cs

public class childmodel     {         public string { get; set; }         public string b { get; set; }     } 

viewmodelbase.cs

 public class viewmodelbase : inotifypropertychanged     {          public void onpropertychanged(string name)         {             if (propertychanged != null)             {                 propertychanged(this, new propertychangedeventargs(name));             }         }          public event propertychangedeventhandler propertychanged;     } 

i see 1 grid per tab. entry on first tab has value of 0 property a. entry of second tab has value of 1 property b.

i see when onpropertychanged called propertychanged null.

i can access datagrid if have in mainwindow.xaml

<grid>         <tabcontrol itemssource="{binding items}">             <tabcontrol.itemtemplate>                 <datatemplate>                     <textblock text="{binding tabtitle}"/>                 </datatemplate>             </tabcontrol.itemtemplate>             <tabcontrol.contenttemplate>                 <datatemplate>                     <datagrid horizontalalignment="stretch" verticalalignment="stretch" autogeneratecolumns="true"                   itemssource="{binding grid}"/>                 </datatemplate>             </tabcontrol.contenttemplate>         </tabcontrol>     </grid> 

but onpropertychanged null , don't see grid

<datatemplate x:key="contenttemplate"                    datatype="{x:type viewmodel:childviewmodel}">      <viewmodel:childview />  </datatemplate> 

your datatemplate empty. question, want along these lines:

<grid>     <grid.resources>         <datatemplate x:key="contenttemplate" targettype="{x:type viewmodel:childviewmodel}">             <datagrid autogeneratecolumns="false" . . .>                 <datagrid.columns>                     <!-- column definitions here -->                 </datagrid.columns>             </datagrid>         </datatemplate>     </grid.resources>     <tabcontrol contenttemplate="{staticresource contenttemplate}"               itemssource="{binding items}" /> </grid>