多用户建站系统源码,广州番禺发现1例阳性,微信网站设计价格,定制化网站开发公司数据绑定是一个很强大且优雅的技能#xff0c;之前用过好多次#xff0c;但有些地方总不是特别清晰#xff0c;常常需要重新翻阅资料来回顾#xff0c;于是这次用了几天时间好好梳理一下#xff0c;记录一下。
首先数据绑定对数据对象的要求#xff1a;需要是公有属性之前用过好多次但有些地方总不是特别清晰常常需要重新翻阅资料来回顾于是这次用了几天时间好好梳理一下记录一下。
首先数据绑定对数据对象的要求需要是公有属性不支持字段和私有属性。
如果需要在数据内容发生变化时自动更新到控件则需要实现INotifyPropertyChanged接口其包含 PropertyChanged事件在属性变化时引发PropertyChanged事件。
如果绑定对象为集合时需要在集合内容发生变化时自动更新到控件则需要INotifyCollectionChanged接口其包含CollectionChanged事件目前内置的泛型集合 ObservableCollection 实现了该接口。
通常在设置绑定时我们需要指定数据上下文DataContext如果控件没有设置DataContext则会去找父容器的DataContext依层级依次查找。也有些控件直接在代码中指定ItemsSource的。如果要绑定的数据依赖于另外一个控件的值可以在DataContext中绑定到另外一个控件的选中项然后设置该控件的数据源或者绑定值。
MainWindow.xaml
Window x:ClassTestBinding.MainWindowxmlnshttp://schemas.microsoft.com/winfx/2006/xaml/presentationxmlns:xhttp://schemas.microsoft.com/winfx/2006/xamlxmlns:dhttp://schemas.microsoft.com/expression/blend/2008xmlns:mchttp://schemas.openxmlformats.org/markup-compatibility/2006xmlns:localclr-namespace:TestBindingmc:IgnorabledTitleMainWindow Height450 Width800StackPanel NameparentContainerStackPanel OrientationHorizontalTextBlockBindData:/TextBlockTextBox Text{Binding PathBindData}/TextBox/StackPanelStackPanel OrientationHorizontalTextBlockBindDatas:/TextBlockListBox NameexchangeListBox ItemsSource{Binding PathExchanges} DisplayMemberPathExchangeID/ListBox/StackPanelStackPanelComboBox NameinstrumentCombbox DataContext{Binding ElementNameexchangeListBox, PathSelectedItem} ItemsSource{Binding PathInstruments} DisplayMemberPathInstrumentID//StackPanelStackPanel OrientationHorizontal DataContext{Binding ElementNameinstrumentCombbox, PathSelectedItem}TextBlockExchangeID:/TextBlockTextBox Text{Binding PathExchangeID}/TextBox/StackPanelStackPanel OrientationHorizontal DataContext{Binding ElementNameinstrumentCombbox, PathSelectedItem}TextBlockInstrumentID:/TextBlockTextBox Text{Binding PathInstrumentID}/TextBox/StackPanelStackPanel OrientationHorizontal DataContext{Binding ElementNameinstrumentCombbox, PathSelectedItem}TextBlockInstrumentName:/TextBlockTextBox Text{Binding PathInstrumentName}/TextBox/StackPanel/StackPanel
/WindowMainWindow.xaml.cs
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Runtime.CompilerServices;
using System.Windows;namespace TestBinding;public class ViewModelBase : INotifyPropertyChanged
{public event PropertyChangedEventHandler? PropertyChanged;protected virtual void OnPropertyChanged([CallerMemberName] string? propertyName null){PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));}protected virtual bool SetPropertyT(ref T member, T value, [CallerMemberName] string? propertyName null){if (EqualityComparerT.Default.Equals(member, value)){return false;}member value;OnPropertyChanged(propertyName);return true;}
}
public class ExchangeViewModel : ViewModelBase
{private string exchangeID string.Empty;public string ExchangeID { get exchangeID; set SetProperty(ref exchangeID, value); }public ObservableCollectionInstrumentViewModel Instruments { get; set; } new ObservableCollectionInstrumentViewModel();
}
public class InstrumentViewModel : ViewModelBase
{public InstrumentViewModel(string exchangeID, string instrumentID, string instrumentName){ExchangeID exchangeID;InstrumentID instrumentID;InstrumentName instrumentName;}private string _exchangeID string.Empty;private string _instrumentID string.Empty;private string _instrumentName string.Empty;public string ExchangeID { get _exchangeID; set SetProperty(ref _exchangeID, value); }public string InstrumentID { get _instrumentID; set SetProperty(ref _instrumentID, value); }public string InstrumentName { get _instrumentName; set SetProperty(ref _instrumentName, value); }
}
/// summary
/// Interaction logic for MainWindow.xaml
/// /summary
public partial class MainWindow : Window
{public MainWindow(){InitializeComponent();parentContainer.DataContext this;Exchanges new();ExchangeViewModel exchange1 new ExchangeViewModel();exchange1.ExchangeID SHSE;exchange1.Instruments.Add(new InstrumentViewModel(SHSE, 601155, 新城控股));exchange1.Instruments.Add(new InstrumentViewModel(SHSE, 600036, 招商银行));exchange1.Instruments.Add(new InstrumentViewModel(SHSE, 600266, 城建发展));exchange1.Instruments.Add(new InstrumentViewModel(SHSE, 600837, 海通证券));exchange1.Instruments.Add(new InstrumentViewModel(SHSE, 601668, 中国建筑));ExchangeViewModel exchange2 new ExchangeViewModel();exchange2.ExchangeID SZSE;exchange2.Instruments.Add(new InstrumentViewModel(SZSE, 000002, 万科A));exchange2.Instruments.Add(new InstrumentViewModel(SZSE, 000001, 平安银行));exchange2.Instruments.Add(new InstrumentViewModel(SZSE, 000623, 吉林敖东));exchange2.Instruments.Add(new InstrumentViewModel(SZSE, 002739, 万达电影));exchange2.Instruments.Add(new InstrumentViewModel(SZSE, 300642, 透景生命));Exchanges.Add(exchange1);Exchanges.Add(exchange2);}public string BindData { get; set; } BindData;public ObservableCollectionExchangeViewModel Exchanges { get; set; }
}
