How to get all checked selected items from Listview in c# WPF

i want to get all the items in listview that the checkbox has checked.

lvwStudent

      <ListView  x:Name="lvwStudent"  IsSynchronizedWithCurrentItem="True"  SelectionMode="Multiple" HorizontalAlignment="Stretch" HorizontalContentAlignment="Center" VerticalContentAlignment="Center">
        <ListView.View>
            <GridView>
                <GridViewColumn  Width="50">
                    <GridViewColumn.CellTemplate>
                        <DataTemplate>
                            <CheckBox x:Name="cboxSelected" Content ="{Binding ID}"   Width="20" Height="20" BorderBrush="#FF0C6161" HorizontalAlignment="Center" HorizontalContentAlignment="Center" Tag="{Binding ID}" IsChecked="{Binding IsChecked}" Checked="cboxSelected_Checked_1" />
                        </DataTemplate>
                    </GridViewColumn.CellTemplate>
                </GridViewColumn>
                <GridViewColumn Header="NO." Width="53">
                    <GridViewColumn.CellTemplate>
                        <DataTemplate >
                            <Label Content ="{Binding ID}" FontSize="14" HorizontalContentAlignment="Center"></Label>
                        </DataTemplate>
                    </GridViewColumn.CellTemplate>
                </GridViewColumn>
                <GridViewColumn Header="STUDENT NAME" Width="auto">
                    <GridViewColumn.CellTemplate>
                        <DataTemplate>
                            <Label Content ="{Binding STUDENT_NAME}" FontSize="14" HorizontalContentAlignment="Center"></Label>
                        </DataTemplate>
                    </GridViewColumn.CellTemplate>
                </GridViewColumn>
            </GridView>
        </ListView.View>
    </ListView>

when i click the select button i want to get all selected ID and store in array............

    private void btnSelect_Click(object sender, RoutedEventArgs e)
    {
       int[] selectedId;

        if(lvwMachine.SelectedItems.Count > 0)
        {

            foreach(..... )
            {
              add all selected id in arrat selectedId
             I dont Know HOW.. PLEASE HELP.. THANK YOU..

            }
         }