关于 WPf TreeView 布局美化得一个问题

悬赏园豆：80 [待解决问题]

想用TreeView实现如下效果

可是做出来确实这样的效果

存在的问题:

1:TreeView 自带的折叠图标怎么也去不掉。
2. 背景图片总是不能从最左边开始。

附上xaml代码：

View Code

<TreeView Name="dictree" ItemsSource="{Binding}" Grid.Row="1" BorderThickness="0" Margin="0">
                <TreeView.Resources>
                    <HierarchicalDataTemplate ItemsSource="{Binding Value}" DataType="{x:Type local:Job}">
                        <TextBlock Text="{Binding Id}"><TextBlock Text="{Binding Name}"></TextBlock></TextBlock>
                    </HierarchicalDataTemplate>
                </TreeView.Resources>

                <TreeView.ItemTemplate>
                    <HierarchicalDataTemplate ItemsSource="{Binding Value}">

                        <TreeViewItem>
                            <TreeViewItem.Background>
                                <ImageBrush ImageSource="tvheadbg.png" />
                            </TreeViewItem.Background>
                            <TreeViewItem.Header>
                                <Border  Name="SelectedBorder"  CornerRadius="3" BorderBrush="#99DEFD"  BorderThickness="1" >
                                    <StackPanel Orientation="Horizontal" Height="29">
                                        <Image Source="tHome.png" Height="16" Width="16" Margin="8,0,0,0"  />
                                        <TextBlock Text="{Binding Key}"  VerticalAlignment="Center" Margin="8,0,0,0"></TextBlock>
                                    </StackPanel>
                                </Border>
                            </TreeViewItem.Header>
                        </TreeViewItem>

                        <HierarchicalDataTemplate.ItemTemplate>
                            <DataTemplate>
                                <StackPanel HorizontalAlignment="Left" Height="29" Orientation="Horizontal"  VerticalAlignment="Center">
                                    <Image Source="tHome.png" Height="16" Width="16" Margin="8,0,0,0"  />
                                    <TextBlock Text="{Binding Name}" Margin="8,0,0,0"></TextBlock>
                                </StackPanel>
                            </DataTemplate>
                        </HierarchicalDataTemplate.ItemTemplate>
                    </HierarchicalDataTemplate>
                </TreeView.ItemTemplate>
            </TreeView>