c# - Cannot Access Command in WPF UserControl's DataGrid Row -

i not able execute command (testcommand) in user control may because datagrid of usercontrol using filedetailslist(list)

the following wpf form , using mvvm

<window>     <tabcontrol>         <tabitem header="result">             <usercontrol:filesearchresult></usercontrol:filesearchresult>         </tabitem>     </tabcontrol> </window> 

the below user control

<usercontrol>     <grid>         <grid.rowdefinitions>             <rowdefinition height="*"></rowdefinition>             <rowdefinition height="30"></rowdefinition>         </grid.rowdefinitions         <datagrid grid.row="0" itemsource="{binding filedetailslist}">             <datagrid.columns>                 <datagridtemplatecolumn>                     <datagridtemplatecolumn.celltemplate>                         <datatemplate>                             <button>view                                 <button.contextmenu>                                     <contextmenu fontsize="11">                                             <menuitem command="{binding testcommand}" commandparameter="{binding fileid}" header="splitter errors"/>                                     </contextmenu>                                 </button.contextmenu>                             </button>                         </datatemplate>                     </datagridtemplatecolumn.celltemplate>                 </datagridtemplatecolumn>                 <datagridtextcolumn binding="{binding fileid}" header="file id"/>                 <datagridtextcolumn binding="{binding filename}" header="file name"/>             <datagrid.columns>         <datagrid grid.row="0">     </grid> </usercontrol> 

the below view model

public class filedetailsviewmodel : inotifypropertychanged {     private list<filedetail> _filedetailslist = new list<filedetail>();      public relaycommand<int32> testcommand { get; private set; }     public filedetailsviewmodel()     {          testcommand = new relaycommand<int>(opentestcommand);     }      private void opentestcommand(int fileid)     {          ///some code     }              public list<filedetail> filedetailslist { { return _filedetailslist; } set { _filedetailslist = value; notifypropertychanged("filedetailslist"); } }      public event propertychangedeventhandler propertychanged;      protected void notifypropertychanged(string property)     {         if (propertychanged != null)         {             propertychanged(this, new propertychangedeventargs(property));         }     } } 

please solve issue

you try work 100%,

 <button tag="{binding path=datacontext, relativesource={relativesource ancestortype={x:type datagrid}}}">                                     view                                     <!--  binding relativesource={relativesource ancestortype={x:type datagrid}}, path=datacontext.  -->                                     <button.contextmenu>                                         <contextmenu fontsize="11">                                             <menuitem command="{binding path=placementtarget.tag.testcommand,                                                                         relativesource={relativesource ancestortype={x:type contextmenu}}}"                                                       commandparameter="{binding fileid}"                                                       header="splitter errors" />                                         </contextmenu>                                     </button.contextmenu>                                 </button>