WPF C# Checkbox controlling a timer -

i'm stuck here. have checkbox. when checked, start timer. when unchecked stop timer. can use here. have tried checked, unchecked, , click events. nothing stopping timer. keeps running...

xaml: (has 3 events show)

<checkbox x:name="cbautorefresh" grid.row="1" cliptobounds="true" horizontalalignment="left" content="enable auto refresh" margin="10,0,0,0" width="150" click="cbautorefresh_click" checked="cbautorefresh_checked" unchecked="cbautorefresh_unchecked" /> 

c#: (all 3 attempts)

private void cbautorefresh_click(object sender, routedeventargs e) {      var atimer = new timer();     if (cbautorefresh.ischecked == true)     {         //start timer:          atimer.elapsed += ontimedevent;         atimer.interval = 60000;         atimer.enabled = true;     }     else     {         atimer.enabled = false;     } }  private void cbautorefresh_checked(object sender, routedeventargs e) {     //start timer:     var atimer = new timer();     atimer.elapsed += ontimedevent;     atimer.interval = 60000;     atimer.enabled = true; }  private void cbautorefresh_unchecked(object sender, routedeventargs e) {     var atimer = new timer {enabled = false}; } 

i tried this, mention @ stack overflow

<checkbox checked="checkboxchanged" unchecked="checkboxchanged"/>  private void checkboxchanged(object sender, routedeventargs e) {   messagebox.show("eureka, changed!"); } 

don't create new timer on every event. declare 1 timer in window object (window field/property), initialize in constructor , work in event handlers. @ moment running multiple timers

<checkbox x:name="cbautorefresh" checked="checkboxchanged" unchecked="checkboxchanged"/> 

public class mywindow() {    private timer _t;    public mywindow()    {       initializecomponent();       _t = new timer();       _t.elapsed += ontimedevent;       _t.interval = 60000;    }     private void checkboxchanged(object sender, routedeventargs e)    {       _t.enabled = cbautorefresh.ischecked;    }     }