WPF-MVVM: Handeling Event from within DataGrid Style -

i develop prism+mef application based on wpf+mvvm, there many datagrids build datagridstyle applied datagrids in modules. style add filter text box in columns headers, , used mvvm light eventtocommand trigger textchanged event when text box text changed this: (this code exist in datagridstyle resource dictionary)

    <textbox x:name="filtertextbox"           horizontalalignment="right" minwidth="25" height="auto"          opacitymask="black" visibility="collapsed"           text=""          textwrapping="wrap" grid.column="0" grid.columnspan="1">              <i:interaction.triggers>                 <i:eventtrigger eventname="textchanged">                     <cmd:eventtocommand command="{binding datacontext.textchangedcommand}"                           passeventargstocommand="true"/>                 </i:eventtrigger>             </i:interaction.triggers>    </textbox> 

then handled textchangedcommand in viewmodel (pertaining view contains data grid)using attached property:

#region textchangedcommand----------------------------------------------------------------------------------------------          static icommand command; //1          public static icommand gettextchangedcommand(dependencyobject obj)         {             return (icommand)obj.getvalue(textchangedcommandproperty);         }          public static void settextchangedcommand(dependencyobject obj, icommand value)         {             obj.setvalue(textchangedcommandproperty, value);         }          // using dependencyproperty backing store textchangedcommand.  enables animation, styling, binding, etc...         public static readonly dependencyproperty textchangedcommandproperty =             dependencyproperty.registerattached("textchangedcommand",                                                  typeof(icommand),                                                   typeof(subsystemallviewmodel),                                                  new uipropertymetadata(null, commandchanged));           static void commandchanged(dependencyobject obj, dependencypropertychangedeventargs e)         {             var fe = obj frameworkelement;             command = e.newvalue icommand;             fe.addhandler(textbox.textchangedevent, new textchangedeventhandler(executecommand));         }          static void executecommand(object sender, textchangedeventargs e)         {             //some  code         }           #endregion 

and view contains grid:

 <datagrid  itemssource="{binding subsystems,mode=twoway, updatesourcetrigger=propertychanged}"                    selecteditem="{binding path=selectedsubsystem, mode=twoway}"                                            name="subsystemalldatagrid"                                  style="{staticresource datagridstyle}"                    grid.row="2">              <datagrid.columns>                 <datagridtextcolumn header="serial" binding="{binding path=serial, mode=twoway}"></datagridtextcolumn>                 <datagridtextcolumn header="type" binding="{binding path=type, mode=twoway}"></datagridtextcolumn>                 <datagridtextcolumn header="system" binding="{binding path=system, mode=twoway}"></datagridtextcolumn>                 <datagridtextcolumn header="subsystemno"  binding="{binding path=subsystemno, mode=twoway}"></datagridtextcolumn>                 <datagridtextcolumn header="description" binding="{binding path=description, mode=twoway}"></datagridtextcolumn>                 <datagridtextcolumn header="scope" binding="{binding path=scope, mode=twoway}"></datagridtextcolumn>                 <datagridtextcolumn header="area" binding="{binding path=area, mode=twoway}"></datagridtextcolumn>                 <datagridtextcolumn header="priority" binding="{binding path=priority, mode=twoway}"></datagridtextcolumn>                 <datagridtextcolumn header="dossierlocation" binding="{binding path=dossierlocation, mode=twoway}"></datagridtextcolumn>                 <datagridtextcolumn header="parts" binding="{binding path=parts, mode=twoway}"></datagridtextcolumn>                 <datagridtextcolumn header="status" binding="{binding path=status, mode=twoway}"></datagridtextcolumn>                 <datagridtextcolumn header="statusdate" binding="{binding path=statusdate, mode=twoway}"></datagridtextcolumn>                 <datagridtextcolumn header="mcdate" binding="{binding path=mcdate, mode=twoway}"></datagridtextcolumn>                 <datagridtextcolumn header="plnmcdate" binding="{binding path=plnmcdate, mode=twoway}"></datagridtextcolumn>                 <datagridtextcolumn header="remark" binding="{binding path=remark, mode=twoway}"></datagridtextcolumn>              </datagrid.columns>          </datagrid> 

the problems are: when enter filter text in text box in 1 of columns headers of data grid nothing happen , break points @ following points not hit:

1-gettextchangedcommand , settextchangedcommand

2-the commandchanged() method.

i'm new wpf i'm sure there faults in wpf or c# code..., please me fixing these faults.

note: don't use code behind.

thanks in advance

looks command-binding doesnt work. try following:

command="{binding path=textchangedcommand}" 

or

command="{binding relativesource={relativesource ancestortype={x:type datagrid}} path=datacontext.textchangedcommand}"