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WPF DataPager控件

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12/01
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最近在项目中遇到远程加载数据的问题,由于服务器采用分页方式返回数据,因此客户端也相应的制作了一个分页控件.代码相对简单,算做入门级的源码.

效果如图:

初步分析,分页功能只需要3个核心变量:PageIndex,PageSize,TotalCount,2个事件:PageChanging,PageChanged,1个方法InitData.

PageIndex:记录当前所在页

PageSize:记录每页显示的条目数

TotalCount:条目总数

由TotalCount和PageSize可以得到PageCount

PageChanging事件作为分页的预处理事件,修改事件参数PageChangingEventArgs的IsCancel属性可以取消分页,这个是参考其他分页控件的属性

PageChanged事件是分页后的处理事件,应用程序可以在此时获取PageIndex进行操作.

InitData方法在数据加载时调用(主要是TotalCount属性),用于初始化上面提到的核心变量.

WPF提供了很强大和实用的Binding功能,在开发控件时,应该尽量把属性设计成依赖属性.因此我把PageIndex,PageSize,TotalCount属性全部设计成依赖属性,并注册了部分回调方法.这样也可以很方便的实现控件和ViewModel的绑定.

核心代码如下:

///
/// DataPager.xaml 的交互逻辑
///
public partial class DataPager : UserControl, INotifyPropertyChanged
{
public DataPager()
{
InitializeComponent();
}
///
/// 分页前处理的事件,如果设置e.IsCancel=True将取消分页
///
public event PageChangingRouteEventHandler PageChanging;
///
/// 分页后处理的事件
///
public event PageChangedRouteEventHandler PageChanged;
#region 依赖属性
///
/// 当前页
///
public int PageIndex
{
get { return ( int )GetValue(PageIndexProperty); }
set { SetValue(PageIndexProperty, value); }
}
// Using a DependencyProperty as the backing store for CurrentPage.  This enables animation, styling, binding, etc...
public static readonly DependencyProperty PageIndexProperty =
DependencyProperty.Register( "PageIndex" , typeof ( int ), typeof (DataPager), new UIPropertyMetadata(1, (sender, e) =>
{
var dp = sender as DataPager;
dp.ChangeNavigationButtonState();
}));
///
/// 每页显示数据大小
///
public int PageSize
{
get { return ( int )GetValue(PageSizeProperty); }
set { SetValue(PageSizeProperty, value); InitData(); }
}
// Using a DependencyProperty as the backing store for PageSize.  This enables animation, styling, binding, etc...
public static readonly DependencyProperty PageSizeProperty =
DependencyProperty.Register( "PageSize" , typeof ( int ), typeof (DataPager), new UIPropertyMetadata(20, (sender, e) =>
{
var dp = sender as DataPager;
if (dp == null ) return ;
dp.ChangeNavigationButtonState();
}));
///
/// 记录数量
///
public int TotalCount
{
get { return ( int )GetValue(TotalCountProperty); }
set
{
SetValue(TotalCountProperty, value);
}
}
// Using a DependencyProperty as the backing store for TotalCount.  This enables animation, styling, binding, etc...
public static readonly DependencyProperty TotalCountProperty =
DependencyProperty.Register( "TotalCount" , typeof ( int ), typeof (DataPager), new UIPropertyMetadata(0, (sender, e) =>
{
var dp = sender as DataPager;
if (dp == null ) return ;
dp.InitData();
dp.ChangeNavigationButtonState();
}));
///
/// 总页数
///
public int PageCount
{
get { return ( int )GetValue(PageCountProperty); }
private set { SetValue(PageCountProperty, value); }
}
// Using a DependencyProperty as the backing store for PageCount.  This enables animation, styling, binding, etc...
public static readonly DependencyProperty PageCountProperty =
DependencyProperty.Register( "PageCount" , typeof ( int ), typeof (DataPager), new UIPropertyMetadata(1));
///
/// 是否可以点击首页和上一页按钮
///
public bool CanGoFirstOrPrev
{
get
{
if (PageIndex <= 1) return false ;
return true ;
}
}
///
/// 是否可以点击最后页和下一页按钮
///
public bool CanGoLastOrNext
{
get
{
if (PageIndex >= PageCount) return false ;
return true ;
}
}
#endregion
///
/// 点击首页按钮
///
///
///
private void btnFirst_Click( object sender, RoutedEventArgs e)
{
OnPageChanging(1);
}
///
/// 点击上一页按钮
///
///
///
private void btnPrev_Click( object sender, RoutedEventArgs e)
{
OnPageChanging( this .PageIndex - 1);
}
///
/// 点击下一页按钮
///
///
///
private void btnNext_Click( object sender, RoutedEventArgs e)
{
OnPageChanging( this .PageIndex + 1);
}
///
/// 点击末页按钮
///
///
///
private void btnLast_Click( object sender, RoutedEventArgs e)
{
OnPageChanging( this .PageCount);
}
///
/// 点击跳转按钮
///
///
///
private void btnGoTo_Click( object sender, RoutedEventArgs e)
{
int pageIndex = 1;
try
{
pageIndex = Convert.ToInt32(txtPageIndex.Text);
}
catch
{
}
finally
{
OnPageChanging(pageIndex);
}
}
///
/// 页码更改
///
///
internal void OnPageChanging( int pageIndex)
{
if (pageIndex < 1) pageIndex = 1;
if (pageIndex > this .PageCount) pageIndex = this .PageCount;
var oldPageIndex = this .PageIndex;
var newPageIndex = pageIndex;
var eventArgs = new PageChangingEventArgs() { OldPageIndex = oldPageIndex, NewPageIndex = newPageIndex };
if ( this .PageChanging != null )
{
this .PageChanging( this , eventArgs);
}
if (!eventArgs.IsCancel)
{
this .PageIndex = newPageIndex;
if ( this .PageChanged != null )
{
this .PageChanged.Invoke( this , new PageChangedEventArgs() { CurrentPageIndex = this .PageIndex });
}
}
}
///
/// 通知导航按钮(首页,上一页,下一页,末页)状态的更改
///
void ChangeNavigationButtonState()
{
this .NotifyPropertyChanged( "CanGoFirstOrPrev" );
this .NotifyPropertyChanged( "CanGoLastOrNext" );
}
///
/// 初始化数据
///
void InitData()
{
if ( this .TotalCount == 0)
{
this .PageCount = 1;
}
else
{
this .PageCount = this .TotalCount % this .PageSize > 0 ? ( this .TotalCount / this .PageSize) + 1 : this .TotalCount / this .PageSize;
}
if ( this .PageIndex < 1)
{
this .PageIndex = 1;
}
if ( this .PageIndex > this .PageCount)
{
this .PageIndex = this .PageCount;
}
if ( this .PageSize < 1)
{
this .PageSize = 20;
}
}
#region INotifyPropertyChanged成员
public event PropertyChangedEventHandler PropertyChanged;
public void NotifyPropertyChanged( string propertyName)
{
if ( this .PropertyChanged != null )
{
this .PropertyChanged.Invoke( this , new PropertyChangedEventArgs(propertyName));
}
}
#endregion
}

Xaml中使用如下:

<my:DataPager PageChanged="dataPager1_PageChanged" PageChanging="dataPager1_PageChanging"  TotalCount="{Binding TotalCount}" PageSize="20" PageIndex="{Binding PageIndex}" x:Name="dataPager1" VerticalAlignment="Top" />

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