windows phone 8 - Mvvm How to get the value txtNmItem with TextChanged method -

how value txtnmitem textchanged method?

<textbox grid.column="1" name="txtnmitem" background="#f3f3f3" borderbrush="#f3f3f3" verticalalignment="top" text="{binding path=snmitem, mode=twoway}">                                         <i:interaction.triggers>                                             <i:eventtrigger eventname="textchanged">                                                 <cmd:eventtocommand command="{binding elementname=listaitem,path=datacontext.salvarcommand}" passeventargstocommand="true"/>                                             </i:eventtrigger>                                         </i:interaction.triggers>                                     </textbox> 

viewmodel

public relaycommand<object> salvarcommand { { return new relaycommand<object>(salvar); } }  private async void salvar(object e)     { 

i assume need textchanged because binding value gets updated after control losses focus. need update property while user typing.

this might help:

view

 <i:interaction.triggers><i:eventtrigger eventname="textchanged">         <cmd:eventtocommand command="{binding salvarcommand}"         commandparameter="{binding elementname=snmitem, path=text}/></i:eventtrigger></i:interaction.triggers> 

viewmodel

public icommand salvarcommand {   {     return new relaycommand<string>((param) =>     {       ...     });   } }