c# - How to select the listbox items from View Model -

i want select list box items view model?

my xaml is:-

<grid x:name="mvvmlistboxuicontainer" grid.row="1" margin="2,0,2,0"> <listbox height="374" itemssource="{binding studentdetails,mode=twoway}" horizontalalignment="left" margin="2,6,0,0" name="listbox1" verticalalignment="top" width="476" borderbrush="#00410d0d">     <i:interaction.triggers>         <i:eventtrigger eventname="tap">             <i:invokecommandaction command="{binding eventpagecommand, mode=oneway}"/>         </i:eventtrigger>     </i:interaction.triggers>     <listbox.itemtemplate>         <datatemplate>             <border borderbrush="gray" padding="5" borderthickness="1">                 <stackpanel orientation="horizontal">                     <border borderbrush="wheat" borderthickness="1">                         <image  name="listpersonimage" source="{binding personimage}" height="100" width="100" stretch="uniform" margin="10,0,0,0"/>                     </border>                     <textblock text="{binding firstname}" name="firstname" width="200" foreground="white" margin="10,10,0,0" fontweight="semibold" fontsize="22"  />                       <button margin="-100,0,0,0" height="80" width="80" datacontext="{binding datacontext, elementname=listbox1}" command="{binding addperson}">                         <button.background>                             <imagebrush imagesource="{binding addimage}" stretch="fill" />                         </button.background>                     </button>                 </stackpanel>             </border>         </datatemplate>     </listbox.itemtemplate> </listbox> 

my view model:-

eventpagecommand = new reactiveasynccommand(); eventpagecommand.subscribe(x => {     messagebox.show("list box item clicked."); }); 

here when click on list box items message box showing. can not show selected items. can show xaml.cs.

private void listbox1_tap(object sender, system.windows.input.gestureeventargs e) {     listbox listbox = (listbox)sender;     listboxeventsmodel items = (listboxeventsmodel)listbox.selecteditem;     messagebox.show("selected name"+items.firstname);     //if(!constants.buttonselected)     //messagebox.show("list item selected..!!"); } 

but when try view model can not show selected items. please let me know how show selected items. have try this:-

eventpagecommand = new reactiveasynccommand(); eventpagecommand.subscribe(x => {     messagebox.show("list box item clicked.");      listbox listbox = (listbox)sender;     listboxeventsmodel items = (listboxeventsmodel)listbox.selecteditem;     messagebox.show("selected name" + items.firstname); }); 

but receiving error:- the name 'sender' not exist in current context

in xaml in listbox:

selecteditem={binding selectedstudent, mode=twoway}

then in viewmodel:

public observablecollection<your_object_here> selecteditems { get; set;}

edit full example:

 <listbox margin="5,0" grid.row="1" grid.rowspan="2" itemssource="{binding roles}" selecteditem="{binding selecteditem, mode=twoway}">         <listbox.itemtemplate>             <datatemplate>                 <textblock text="{binding path=title}" />             </datatemplate>         </listbox.itemtemplate>     </listbox> 

viewmodel

public class rolesviewmodel : baseviewmodel {     private collection<bo.rolebo> roles;     private bo.rolebo selecteditem;      public bo.rolebo selecteditem     {         { return selecteditem; }         set          {              selecteditem = value;             notifyonpropertychanged("selecteditem");          }     }      public collection<bo.rolebo> roles     {         { return roles; }         set { roles = value; notifyonpropertychanged("roles"); }     }  }