how to refer the check box control present inside listview control in wpf

I am having checkbox inside listview . i want to refer the checkbox from button click event

i tried this code

                 CheckBox myTextbox = GetTemplateChild("chb_standard") as CheckBox;
                CheckBox  myTextBlock = (CheckBox)this.FindName("chb_standard");

it will return only a null object

i also tried find visual child format

 private childItem FindVisualChild<childItem>(DependencyObject obj)
         where childItem : DependencyObject
        {
            for (int i = 0; i < VisualTreeHelper.GetChildrenCount(obj); i++)
            {
                DependencyObject child = VisualTreeHelper.GetChild(obj, i);
                if (child != null && child is childItem)
                    return (childItem)child;
                else
                {
                    childItem childOfChild = FindVisualChild<childItem>(child);
                    if (childOfChild != null)
                        return childOfChild;
                }
            }
            return null;
        }

for (int k = 0; k <= listView1.Items.Count - 1; k++)
            {
                ListViewData lvc = (ListViewData)listView1.Items[k];
                //var chb_standard = sender as CheckBox;


                ListViewItem ListBoxItemObj =(ListViewItem)listView1.ItemContainerGenerator.ContainerFromItem(listView1.Items[k]);
                //bool check = ListBoxItemObj.HasContent;
                // find a ContentPresenter of that list item.. [Call FindVisualChild Method]
                ContentPresenter ContentPresenterObj = FindVisualChild<ContentPresenter>(ListBoxItemObj);

                // call FindName on the DataTemplate of that ContentPresenter
                DataTemplate DataTemplateObj = ContentPresenterObj.ContentTemplate;
                CheckBox Chk = (CheckBox)DataTemplateObj.FindName("chb_standard", ContentPresenterObj);
                Chk.IsChecked = true;

            }

ListBoxItemObj  will return always null actually i am having values in listview

so is there another method to refer the checkbox send some code example or link