我正在使用MVVM(MVVM Light Toolkit)并在视图模型上有一个属性,它公开了一个对象列表。对象包含两个属性,两个字符串,与缩写和描述相关。我希望ComboBox将配对公开为“缩写 - 描述”。如果我使用数据模板,它很容易做到。
我在视图模型上有另一个属性,它表示应该显示为选中的对象 - ComboBox中的选定项。我将ItemsSource绑定到列表,因为它表示可用选择的范围,并且我尝试将SelectedItem绑定到此对象。我正在自杀,试图找出为什么我无法让它工作,并且感觉更像是一小时的欺诈行为。
在尝试了解其工作原理时,我只使用一个字符串列表和一个选定的字符串创建了相同的方法。这非常有效。所以,它显然与打字有关......也许选择平等的东西?或者它可能与数据模板有关?
这是XAML:
<Window x:Class="MvvmLight1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow"
Height="300"
Width="300"
DataContext="{Binding Main, Source={StaticResource Locator}}">
<Window.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="Skins/MainSkin.xaml" />
</ResourceDictionary.MergedDictionaries>
<DataTemplate x:Key="DataTemplate1">
<StackPanel Orientation="Horizontal">
<TextBlock TextWrapping="Wrap" Text="{Binding CourtCode}"/>
<TextBlock TextWrapping="Wrap" Text=" - "/>
<TextBlock TextWrapping="Wrap" Text="{Binding CourtDescription}"/>
</StackPanel>
</DataTemplate>
</ResourceDictionary>
</Window.Resources>
<Grid x:Name="LayoutRoot">
<ComboBox x:Name="cmbAbbrevDescriptions" Height="35" Margin="25,75,25,25" VerticalAlignment="Top" ItemsSource="{Binding Codes}" ItemTemplate="{DynamicResource DataTemplate1}" SelectedItem="{Binding selectedCode}" />
<ComboBox x:Name="cmbStrings" Height="35" Margin="25" VerticalAlignment="Top" ItemsSource="{Binding strs}" SelectedItem="{Binding selectedStr}"/>
</Grid>
</Window>
并且,如果有用,这里是ViewModel:
using GalaSoft.MvvmLight;
using MvvmLight1.Model;
using System.Collections.Generic;
namespace MvvmLight1.ViewModel
{
public class MainViewModel : ViewModelBase
{
public const string CodesPropertyName = "Codes";
private List<Court> _codes = null;
public List<Court> Codes
{
get
{
return _codes;
}
set
{
if (_codes == value)
{
return;
}
var oldValue = _codes;
_codes = value;
// Update bindings and broadcast change using GalaSoft.Utility.Messenging
RaisePropertyChanged(CodesPropertyName, oldValue, value, true);
}
}
public const string selectedCodePropertyName = "selectedCode";
private Court _selectedCode = null;
public Court selectedCode
{
get
{
return _selectedCode;
}
set
{
if (_selectedCode == value)
{
return;
}
var oldValue = _selectedCode;
_selectedCode = value;
// Update bindings and broadcast change using GalaSoft.Utility.Messenging
RaisePropertyChanged(selectedCodePropertyName, oldValue, value, true);
}
}
public const string strsPropertyName = "strs";
private List<string> _strs = null;
public List<string> strs
{
get
{
return _strs;
}
set
{
if (_strs == value)
{
return;
}
var oldValue = _strs;
_strs = value;
// Update bindings and broadcast change using GalaSoft.Utility.Messenging
RaisePropertyChanged(strsPropertyName, oldValue, value, true);
}
}
public const string selectedStrPropertyName = "selectedStr";
private string _selectedStr = "";
public string selectedStr
{
get
{
return _selectedStr;
}
set
{
if (_selectedStr == value)
{
return;
}
var oldValue = _selectedStr;
_selectedStr = value;
// Update bindings and broadcast change using GalaSoft.Utility.Messenging
RaisePropertyChanged(selectedStrPropertyName, oldValue, value, true);
}
}
/// <summary>
/// Initializes a new instance of the MainViewModel class.
/// </summary>
public MainViewModel()
{
Codes = new List<Court>();
Court code1 = new Court();
code1.CourtCode = "ABC";
code1.CourtDescription = "A Court";
Court code2 = new Court();
code2.CourtCode = "DEF";
code2.CourtDescription = "Second Court";
Codes.Add(code1);
Codes.Add(code2);
Court code3 = new Court();
code3.CourtCode = "DEF";
code3.CourtDescription = "Second Court";
selectedCode = code3;
selectedStr = "Hello";
strs = new List<string>();
strs.Add("Goodbye");
strs.Add("Hello");
strs.Add("Ciao");
}
}
}
这是一个暴露无聊的琐碎课程:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace MvvmLight1.Model
{
public class Court
{
public string CourtCode { get; set; }
public string CourtDescription { get; set; }
}
}
谢谢!
答案 0 :(得分:1)
运行时不知道code2和code3应该相等。
请参阅http://msdn.microsoft.com/en-us/library/ms173147(VS.80).aspx
public override bool Equals(object o)
{
var court = o as Court;
if(court == null)
return false;
return CourtCode == court.CourtCode;
}
答案 1 :(得分:0)
您的SelectedCode Code3不在Codes集合中。添加它以便选择按预期工作。
您的selectedStr有效,因为它位于集合中。 [strs.Add("Hello");]