CommandParameter="{Binding}"

改為

CommandParameter="{Binding DataContext,RelativeSource={RelativeSource Self}}"

                            <StackPanel Orientation="Horizontal" >
                                <Button Content="×" CommandParameter="{Binding DataContext,RelativeSource={RelativeSource Self}}
 
" Command="{Binding RelativeSource={RelativeSource AncestorType=Window}, Path=DataContext.CmdConvertToFalse}"></Button>
                                <Button Content="√" CommandParameter="{Binding DataContext,RelativeSource={RelativeSource Self}}" Command="{Binding RelativeSource={RelativeSource AncestorType=Window}, Path=DataContext.CmdConvertToTrue}
 
"></Button>
                            </StackPanel>