Windows 8 系列 GirdView 滚动事件获取 随笔

XAML：

  <GridView
       x:Name="itemGridView"  >

            <GridView.ItemsPanel>
                <ItemsPanelTemplate>
                    <VirtualizingStackPanel Orientation="Horizontal"/>
                </ItemsPanelTemplate>
            </GridView.ItemsPanel>
            <GridView.GroupStyle>
                <GroupStyle>
                    <GroupStyle.HeaderTemplate>
                        <DataTemplate>
                            <Grid Margin="1,0,0,6">
                                <Button
                                    AutomationProperties.Name="Group Title"
                                    Click="Header_Click"
                                    Style="{StaticResource TextPrimaryButtonStyle}" >
                                    <StackPanel Orientation="Horizontal">
                                        <TextBlock Text="{Binding Title}" Margin="3,-7,10,10" Style="{StaticResource GroupHeaderTextStyle}" />
                                        <TextBlock Text="{StaticResource ChevronGlyph}" FontFamily="Segoe UI Symbol" Margin="0,-7,0,10" Style="{StaticResource GroupHeaderTextStyle}"/>
                                    </StackPanel>
                                </Button>
                            </Grid>
                        </DataTemplate>
                    </GroupStyle.HeaderTemplate>
                    <GroupStyle.Panel>
                        <ItemsPanelTemplate>
                          
                            <VariableSizedWrapGrid Orientation="Vertical" Margin="0,0,80,0"/>
                          
                        </ItemsPanelTemplate>
                    </GroupStyle.Panel>
                    
                </GroupStyle>
            </GridView.GroupStyle>
        </GridView>

.cs:

 /// <summary>
       /// 根据名称找到控件的内容控件
       /// </summary>
       /// <typeparam name="T"></typeparam>
       /// <param name="parent"></param>
       /// <param name="name"></param>
       /// <returns></returns>
        public T FindVisualChildByName<T>(DependencyObject parent, string name) where T : DependencyObject
        {
            for (int i = 0; i < VisualTreeHelper.GetChildrenCount(parent); i++)
            {
                var child = VisualTreeHelper.GetChild(parent, i);
                string controlName = child.GetValue(Control.NameProperty) as string;
                if (controlName == name)
                {
                    return child as T;
                }
                else
                {
                    T result = FindVisualChildByName<T>(child, name);
                    if (result != null)
                        return result;
                }
            }
            return null;
        }

XAML-.cs:

 　　　　　　　　 //找到gridview中的 scrollViewer 、 scrollBar 注册值改变事件
                //Tip 获取该事件要在绑定数据后才去注册，不然获取不到scrollviewer 
                var scrollViewer = this.FindVisualChildByName<ScrollViewer>(this.itemGridView, "ScrollViewer");
　　　　　　　　　//找到水平的滚轴
                var scroollBar = this.FindVisualChildByName<ScrollBar>(scrollViewer, "HorizontalScrollBar");
                scroollBar.ValueChanged += scroollBar_ValueChanged;
                

  private void scroollBar_ValueChanged(object sender, RangeBaseValueChangedEventArgs e)
        {
            ScrollBar scrollbar = sender as ScrollBar;
            //当滚轴值为最大时并且没有在加载数据时
            if (e.NewValue == scrollbar.Maximum && !isLoading)
            {
               //异步加载数据
               LoadData();
               
                //设置滚轴的值偏移点，以便再次出发valueChanged事件
                 scrollbar.Value = e.NewValue - 1E-8;
            }
            if (e.NewValue == scrollbar.Minimum)
            { 
            
            }
        }