• 自定义控件DataPager


       在最近的一个项目中,涉及到一个自定义翻页控制的控件,下面就这一个控件做详细的说明,这个自定义控件的主要作用是对数据源进行翻页控制,比如说:“上一页、下一页、首页、末页”等相关操作,由于在一个项目中有多个界面要用到这一部分,所以我们将其封装成一个自定义控件,从而使软件整体结构更加清楚明了,首先我们来将控件的界面展示出来。

        整个控件可以分成三个部分,最左边是一个Combobox控件,中间是常见的上一页、下一页、向前、向后操作,最右边是显示当前记录。下面我们重点来介绍中间部分的封装,在这里我们将每一个按钮封装成一个ImageButton控件,这里我们贴出相应的前台、后台代码,从而从整体上进行分析。   

    <Button x:Class="CustomControlLibrary.ImageButton"
                 xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                 xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
                 xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
                 mc:Ignorable="d" x:Name="loc"
                 d:DesignHeight="44" d:DesignWidth="75">
        <Button.Resources>
            <ResourceDictionary Source="Themes/Generic.xaml" />
        </Button.Resources>
        <Image Name="innerImage" Source="{Binding ImageSource,ElementName=loc}" Stretch="None" />
    </Button>
    

      这里前台的代码比较简单,我们将Button的样式写在了一个资源字典中,同时在Button上面放置一个Image控件,从而组成我们的ImageButton控件,在后台的代码中我们主要定义了两个依赖项属性,ImageSource和GrayImageSource,ImageSource是当按钮正常使用的时候,其显示的背景,GrayImageSource是当按钮的IsEnable=false的时候,其显示的背景,这里先贴出其后台代码。

    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;
    using System.Windows;
    using System.Windows.Controls;
    using System.Windows.Data;
    using System.Windows.Documents;
    using System.Windows.Input;
    using System.Windows.Media;
    using System.Windows.Media.Imaging;
    using System.Windows.Navigation;
    using System.Windows.Shapes;
    
    namespace CustomControlLibrary {
        /// <summary>
        /// ImageButton.xaml 的交互逻辑
        /// </summary>
        public partial class ImageButton : Button 
          {
            public ImageButton() 
             {
                InitializeComponent();
                this.Style = this.FindResource("ImageButtonStyle") as Style;
                this.IsEnabledChanged += new DependencyPropertyChangedEventHandler(ImageButton_IsEnabledChanged);
             }
            void ImageButton_IsEnabledChanged(object sender, DependencyPropertyChangedEventArgs e) 
             {
                if (this.IsEnabled && ImageSource != null)
                 {
                    innerImage.Source = ImageSource;
                 } else if (!this.IsEnabled && GrayImageSource != null) 
                 {
                    innerImage.Source = GrayImageSource;
                 }
              }
    
            public ImageSource ImageSource
             {
                get { return (ImageSource)GetValue(ImageSourceProperty); }
                set { SetValue(ImageSourceProperty, value); }
             }
            // Using a DependencyProperty as the backing store for ImageSource.  This enables animation, styling, binding, etc...
            public static readonly DependencyProperty ImageSourceProperty =
                DependencyProperty.Register("ImageSource", typeof(ImageSource), typeof(ImageButton), new UIPropertyMetadata(null));
    
            public ImageSource GrayImageSource 
             {
                get { return (ImageSource)GetValue(GrayImageSourceProperty); }
                set { SetValue(GrayImageSourceProperty, value); }
             }
    
            // Using a DependencyProperty as the backing store for GrayImageSource.  This enables animation, styling, binding, etc...
            public static readonly DependencyProperty GrayImageSourceProperty =
                DependencyProperty.Register("GrayImageSource", typeof(ImageSource), typeof(ImageButton), new UIPropertyMetadata(null));
    
            public override void OnApplyTemplate() 
            {
                base.OnApplyTemplate();
                if (this.IsEnabled && ImageSource != null) 
                {
                    innerImage.Source = ImageSource;
                } else if (!this.IsEnabled && GrayImageSource != null) 
                {
                    innerImage.Source = GrayImageSource;
                }
            }
        }
    } 

      这里首先分析一下WPF的依赖项属性和普通的.net属性有什么不同,依赖属性是WPF平台中一个新增的概念,出现的目的是用来实现WPF中的样式、自动绑定及实现动画等特性。依赖属性的出现是WPF这种特殊的呈现原理派生出来的,与.NET普通属性不同的是,依赖属性的值是依靠多个提供程序来判断的,并且其具有内建的传递变更通知的能力。

    依赖属性的定义与普通的.NET属性的定义有区别,普通的.NET属性定义只需要定义其set和get区块的赋值与设置即可,而依赖属性需要向.NET的属性系统进行注册。这里我们定义了ImageSource和GrayImageSource两个依赖项属性。另外这里还重写了基类的OnApplyTemplate方法,这个方法是FrameworkElement中定义的方法,在派生类中重写后,每当应用程序代码或内部进程调用 ApplyTemplate,都将调用此方法。FrameworkElement 派生类可以使用 OnApplyTemplate 类处理程序获知显式调用或由布局系统调用此方法的情况。OnApplyTemplate 在完全生成模板并将其附加到逻辑树之后调用。

        然后就是具体的DataPager控件的实现了,这里也分别贴出相应的前台和后台的代码。    

    <UserControl x:Class="CustomControlLibrary.DataPager"  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                 xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
                 xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
                 xmlns:loc="clr-namespace:CustomControlLibrary"
                 x:Name="dp" Margin="3"
                 mc:Ignorable="d" 
                 d:DesignHeight="46" d:DesignWidth="590" Loaded="DataPager_Loaded">  
        <Grid>
            <!--<Grid.Resources>
                <Style TargetType="{x:Type Image}">
                    <Setter Property="Margin" Value="3,0,3,0" />
                    <Setter Property="Cursor" Value="Hand" />
                </Style>
            </Grid.Resources>-->
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="Auto" />
                <ColumnDefinition />
                <ColumnDefinition Width="Auto" />
            </Grid.ColumnDefinitions>
            <ComboBox Grid.Column="0"  VerticalAlignment="Center" Name="cboPageSize"
                      MinWidth="40" Margin="5,0,0,0"   ItemsSource="{Binding Path=PageSizeItems,ElementName=dp}" 
                      SelectedItem="{Binding PageSize,Mode=TwoWay,ElementName=dp}" SelectionChanged="cbpPageSize_SelectionChanged"  Visibility="Visible"/>
            <StackPanel Grid.Column="1" VerticalAlignment="Center" Orientation="Horizontal" Margin="5,0,0,0">
                <loc:ImageButton Click="btnFirst_Click" x:Name="btnFirst"
                    ImageSource="/CustomControlLibrary;component/Images/pagination_first.gif" 
                    GrayImageSource="/CustomControlLibrary;component/Images/pagination_first_gray.gif" />
                <loc:ImageButton Click="btnPrev_Click" x:Name="btnPrev"
                    ImageSource="/CustomControlLibrary;component/Images/pagination_prev.gif" 
                    GrayImageSource="/CustomControlLibrary;component/Images/pagination_prev_gray.gif" />
                <TextBlock Text="第页 "  VerticalAlignment="Center"/>
                <TextBox Width="30" Text="{Binding Path=PageIndex,ElementName=dp}" Name="tbPageIndex" PreviewKeyDown="tbPageIndex_PreviewKeyDown" LostFocus="tbPageIndex_LostFocus" />
                <TextBlock Text=" 共 "  VerticalAlignment="Center"/>
                <TextBlock Text="{Binding Path=PageCount, ElementName=dp}"  VerticalAlignment="Center"/>
                <loc:ImageButton Click="btnNext_Click" x:Name="btnNext"
                    ImageSource="/CustomControlLibrary;component/Images/pagination_next.gif" 
                    GrayImageSource="/CustomControlLibrary;component/Images/pagination_next_gray.gif" />
                <loc:ImageButton Click="btnLast_Click" x:Name="btnLast"
                    ImageSource="/CustomControlLibrary;component/Images/pagination_last.gif" 
                    GrayImageSource="/CustomControlLibrary;component/Images/pagination_last_gray.gif" />
                <!--<loc:ImageButton Click="btnRefresh_Click"
                    ImageSource="/CustomControlLibrary;component/Images/pagination_load.png"  Visibility="Hidden"/>-->
            </StackPanel>
            <TextBlock Grid.Column="2" VerticalAlignment="Center" Margin="5,0,5,0" >显示记录 
                <TextBlock Text="{Binding Path=Start,ElementName=dp}" /> 到 <TextBlock Text="{Binding Path=End,ElementName=dp}"/> 共 <TextBlock Text="{Binding Path=Total,ElementName=dp}"/> 条记录
            </TextBlock>
        </Grid>
    </UserControl>
    

      这里重点介绍后台的逻辑代码。

    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;
    using System.Windows;
    using System.Windows.Controls;
    using System.Windows.Data;
    using System.Windows.Documents;
    using System.Windows.Input;
    using System.Windows.Media;
    using System.Windows.Media.Imaging;
    using System.Windows.Navigation;
    using System.Windows.Shapes;
    using System.ComponentModel;
    
    namespace CustomControlLibrary {
        /// <summary>
        /// DataPager.xaml 的交互逻辑
        /// </summary>
        public partial class DataPager : UserControl, INotifyPropertyChanged 
        {
            public DataPager() 
            {
                InitializeComponent();
            }
    
            #region 依赖属性和事件
            public string PageSizeList
            {
                get { return (string)GetValue(PageSizeListProperty); }
                set { SetValue(PageSizeListProperty, value); }
            }
    
            // Using a DependencyProperty as the backing store for PageSizeList.  This enables animation, styling, binding, etc...
            public static readonly DependencyProperty PageSizeListProperty =
                DependencyProperty.Register("PageSizeList", typeof(string), typeof(DataPager), new UIPropertyMetadata("5,10,20", (s, e) =>
                {
                    DataPager dp = s as DataPager;
                    if (dp.PageSizeItems == null) 
                        dp.PageSizeItems = new List<int>();
                    else 
                        dp.PageSizeItems.Clear();
                    dp.RaisePropertyChanged("PageSizeItems");
                }));
    
            public int PageSize 
            {
                get { return (int)GetValue(PageSizeProperty); }
                set { SetValue(PageSizeProperty, value); }
            }
    
            // 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(16));
    
            public int Total 
            {
                get { return (int)GetValue(TotalProperty); }
                set { SetValue(TotalProperty, value); }
            }
    
            // Using a DependencyProperty as the backing store for Total.  This enables animation, styling, binding, etc...
            public static readonly DependencyProperty TotalProperty =
                DependencyProperty.Register("Total", typeof(int), typeof(DataPager), new UIPropertyMetadata(0));
    
            public int PageIndex 
            {
                get { return (int)GetValue(PageIndexProperty); }
                set { SetValue(PageIndexProperty, value); }
            }
    
            // Using a DependencyProperty as the backing store for PageIndex.  This enables animation, styling, binding, etc...
            public static readonly DependencyProperty PageIndexProperty =
                DependencyProperty.Register("PageIndex", typeof(int), typeof(DataPager), new UIPropertyMetadata(1));
           
    
            public IEnumerable<object> ItemsSource 
            {
                get { return (IEnumerable<object>)GetValue(ItemsSourceProperty); }
                set { SetValue(ItemsSourceProperty, value); }
            }
    
            /// <summary>
            /// ItemsSource数据源
            /// </summary>
            public static readonly DependencyProperty ItemsSourceProperty =
                DependencyProperty.Register("ItemsSource", typeof(IEnumerable<object>), typeof(DataPager), new UIPropertyMetadata(null));        
    
            public static readonly RoutedEvent PageChangedEvent = EventManager.RegisterRoutedEvent("PageChanged", RoutingStrategy.Bubble, typeof(PageChangedEventHandler), typeof(DataPager));
            /// <summary>
            /// 分页更改事件
            /// </summary>
            public event PageChangedEventHandler PageChanged
            {
                add 
                {
                    AddHandler(PageChangedEvent, value);
                }
                remove 
                {
                    RemoveHandler(PageChangedEvent, value);
                }
            }
            #endregion
    
    
            #region 通知属性
            private List<int> _pageSizeItems;
            /// <summary>
            /// 显示每页记录数集合
            /// </summary>
            public List<int> PageSizeItems 
            {
                get 
                {
                    if (_pageSizeItems == null) 
                    {
                        _pageSizeItems = new List<int>();
                    }
                    if (PageSizeList != null) 
                    {
                        List<string> strs = PageSizeList.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries).ToList();
                        _pageSizeItems.Clear();
                        strs.ForEach(c => {
                            _pageSizeItems.Add(Convert.ToInt32(c));
                        });
                    }
                    return _pageSizeItems;
                }
                set 
                {
                    if (_pageSizeItems != value) 
                    {
                        _pageSizeItems = value;
                        RaisePropertyChanged("PageSizeItems");
                    }
                }
            }
    
            private int _pageCount;
            /// <summary>
            /// 总页数
            /// </summary>
            public int PageCount
            {
                get { return _pageCount; }
                set 
                {
                    if (_pageCount != value)
                    {
                        _pageCount = value;
                        RaisePropertyChanged("PageCount");
                    }
                }
            }
    
            private int _start;
            /// <summary>
            /// 开始记录数
            /// </summary>
            public int Start 
            {
                get { return _start; }
                set 
                {
                    if (_start != value) 
                    {
                        _start = value;
                        RaisePropertyChanged("Start");
                    }
                }
            }
    
            private int _end;
            /// <summary>
            /// 结束记录数
            /// </summary>
            public int End
            {
                get { return _end; }
                set 
                {
                    if (_end != value)
                    {
                        _end = value;
                        RaisePropertyChanged("End");
                    }
                }
            }
    
            public event PropertyChangedEventHandler PropertyChanged;
            public void RaisePropertyChanged(string propertyName) 
            {
                if (PropertyChanged != null) 
                {
                    PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
                }
            }
            #endregion
    
            #region 字段、属性、委托
            public delegate void PageChangedEventHandler(object sender, PageChangedEventArgs args);
            private PageChangedEventArgs pageChangedEventArgs; 
            #endregion
    
            #region 引发分页更改事件
            /// <summary>
            /// 引发分页更改事件
            /// </summary>
            private void RaisePageChanged() 
            {
                if (pageChangedEventArgs == null) 
                {
                    pageChangedEventArgs = new PageChangedEventArgs(PageChangedEvent, PageSize, PageIndex);
                } 
                else 
                {
                    pageChangedEventArgs.PageSize = this.PageSize;
                    pageChangedEventArgs.PageIndex = this.PageIndex;
                }
                RaiseEvent(pageChangedEventArgs);
                //calc start、end
                if (ItemsSource != null) 
                {
                    int curCount = ItemsSource.Count();
                    Start = (PageIndex - 1) * PageSize + 1;
                    End = Start + curCount - 1;
    
                    if (Total % PageSize != 0) 
                    {
                        PageCount = Total / PageSize + 1;
                    } 
                    else 
                    {
                        PageCount = Total / PageSize;
                    }
                } 
                else 
                {
                    Start = End = PageCount = Total = 0;
                }
                //调整图片的显示
                btnFirst.IsEnabled = btnPrev.IsEnabled = (PageIndex != 1);
                btnNext.IsEnabled = btnLast.IsEnabled = (PageIndex != PageCount);
            } 
            #endregion
    
            #region 分页操作事件
            void DataPager_Loaded(object sender, RoutedEventArgs e)
            {
                RaisePageChanged();
            }
    
            private void cbpPageSize_SelectionChanged(object sender, SelectionChangedEventArgs e) 
            {
                if (this.IsLoaded) 
                {
                    PageSize = (int)cboPageSize.SelectedItem;
                    RaisePageChanged();
                }
            }
    
            private void btnFirst_Click(object sender, RoutedEventArgs e) 
            {
                PageIndex = 1;
                RaisePageChanged();
            }
    
            private void btnPrev_Click(object sender, RoutedEventArgs e) 
            {
                if (PageIndex > 1) 
                {
                    --PageIndex;
                }
                RaisePageChanged();
            }
    
            private void btnNext_Click(object sender, RoutedEventArgs e) 
            {
                if (Total % PageSize != 0) 
                {
                    PageCount = Total / PageSize + 1;
                } 
                else 
                {
                    PageCount = Total / PageSize;
                }
    
                if (PageIndex < PageCount) 
                {
                    ++PageIndex;
                }
                RaisePageChanged();
            }
    
            private void btnLast_Click(object sender, RoutedEventArgs e) 
            {
                if (Total % PageSize != 0) 
                {
                    PageCount = Total / PageSize + 1;
                } 
                else
                {
                    PageCount = Total / PageSize;
                }
                PageIndex = PageCount;
                RaisePageChanged();
            }
    
            private void btnRefresh_Click(object sender, RoutedEventArgs e) 
            {
                RaisePageChanged();
            }
    
            private void tbPageIndex_PreviewKeyDown(object sender, KeyEventArgs e)
            {
                if (e.Key == Key.Enter) 
                {
                    tbPageIndex_LostFocus(sender, null);
                }
            }
    
            private void tbPageIndex_LostFocus(object sender, RoutedEventArgs e) 
            {
                int pIndex = 0;
                try 
                {
                    pIndex = Convert.ToInt32(tbPageIndex.Text);
                } catch { pIndex = 1; }
    
                if (pIndex < 1) PageIndex = 1;
                else if (pIndex > PageCount) PageIndex = PageCount;
                else PageIndex = pIndex;
    
                RaisePageChanged();
            } 
            #endregion 
            
        }
    
        /// <summary>
        /// 分页更改参数
        /// </summary>
        public class PageChangedEventArgs : RoutedEventArgs
        {
            public int PageSize { get; set; }
            public int PageIndex { get; set; }
    
            public PageChangedEventArgs(RoutedEvent routeEvent, int pageSize, int pageIndex)
                : base(routeEvent) 
            {
                this.PageSize = pageSize;
                this.PageIndex = pageIndex;
            }
        }
    }
    

      这里定义了一些该控件要使用的一些属性,PageSize属性用于定义每一页中的项的数量,Total属性定义总共有多少项,PageIndex定义当前的页码,ItemsSource用于定义数据源的集合,类型是IEnumerable<object>类型,这个里面定义的最重要的函数是RaisePageChanged,该函数将引发分页更改事件,在这个函数中我们将当前定义的路由事件PageChangedEvent,以及每一页项目的大小,以及当前页码传递到PageChangedEventArgs的一个对象中,然后调用RaiseEvent来引发特定的路由事件,这里需要注意的是必须将当前定义的路由事件传递到基类RoutedEventArgs中,否则不能触发该路由事件。

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  • 原文地址:https://www.cnblogs.com/seekdream/p/4843927.html
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