我很想知道为什么我的代码无法正常工作。
我要在EditIncidentViewModel中的列表中删除或添加项目，并使用IEventAggregator将列表传递到DisplayIncidentViewModel中的组合框，但是我无法刷新这些项目。
最初在DisplayIncidentViewModel中，列表是通过解析文本文件填充的，我如何获得更新的列表？
这是DisplayIncidentViewModel：
namespace WpfUI.ViewModels
{
public class DisplayIncidentViewModel : Screen, IHandle<BindableCollection<Incident>>
{
private Incident _selectedIncident;
private string _firstName;
private string _resolutionText;
private bool _hasOptions;
private bool _isChecked;
private string output = "";
private string _text;
private IEventAggregator _events;
public string FirstName
{
get { return _firstName; }
set
{
_firstName = value;
NotifyOfPropertyChange(() => FirstName);
NotifyOfPropertyChange(() => ResolutionText);
}
}
public string ResolutionText
{
get { return CreateResolutionText(); }
set
{
_resolutionText = value;
NotifyOfPropertyChange(() => ResolutionText);
}
}
public bool HasOptions
{
get
{
if (SelectedIncident == null)
{
Incident inc = new Incident();
SelectedIncident = inc;
_isChecked = false;
return false;
}
if (string.IsNullOrWhiteSpace(SelectedIncident.Option))
{
_isChecked = false;
return false;
}
else return true;
}
set
{
_hasOptions = value;
NotifyOfPropertyChange(() => HasOptions);
}
}
public bool IsChecked
{
get { return _isChecked; }
set
{
if (_isChecked == value) return;
_isChecked = value;
NotifyOfPropertyChange(() => IsChecked);
NotifyOfPropertyChange(() => ResolutionText);
}
}
public string Text
{
get { return _text; }
set {
_text = value;
NotifyOfPropertyChange(() => Text);
}
}
public DisplayIncidentViewModel(IEventAggregator events)
{
_events = events;
var parser = new JsonParser();
parser.JsonLoadFile();
var list = parser.SortIncidentsByName();
foreach (var item in list)
{
Incidents.Add(new Incident
{
Name = item.Name,
Description = item.Description,
OtherDescription = item.OtherDescription,
Option = item.Option
});
}
Incidents.Refresh();
}
#region Combobox
// this is the backend that fires-up combobox with the values from json file
public BindableCollection<Incident> Incidents { get; set; } = new BindableCollection<Incident>();
public Incident SelectedIncident
{
get { return _selectedIncident; }
set
{
_selectedIncident = value;
IsChecked = false;
NotifyOfPropertyChange(() => SelectedIncident);
NotifyOfPropertyChange(() => ResolutionText);
NotifyOfPropertyChange(() => HasOptions);
NotifyOfPropertyChange(() => Text);
}
}
#endregion
public string CreateResolutionText()
{
if (SelectedIncident == null)
{
Incident inc = new Incident();
SelectedIncident = inc;
var nou = inc.Description;
SelectedIncident.Description = nou;
NotifyOfPropertyChange(() => SelectedIncident);
}
if (FirstName != "" && !string.IsNullOrWhiteSpace(SelectedIncident.Name))
{
if (!IsChecked)
{
output = $"{ FirstName },{Environment.NewLine}{SelectedIncident.Description}{Environment.NewLine}{Environment.NewLine}{ Globals.GetUsersFirstName(Globals.UserName) }";
Clipboard.SetText(output);
}
if (IsChecked)
{
output = $"{ FirstName },{Environment.NewLine}{SelectedIncident.OtherDescription}{Environment.NewLine}{Environment.NewLine}{ Globals.GetUsersFirstName(Globals.UserName) }";
Clipboard.SetText(output);
}
switch (SelectedIncident.Name)
{
case "Message":
Text = $"Dummy text here";
_events.PublishOnUIThread(new StatusText(Text));
break;
default:
_events.PublishOnUIThread(new StatusText($"Text copied to cliboard"));
break;
}
}
return output;
}
public void Handle(BindableCollection<Incident> message)
{
Incidents.Clear();
Incidents = message;
NotifyOfPropertyChange(() => Incidents);
}
}
}
这是EditIncidentViewModel：
public class EditIncidentViewModel : Screen
{
private IEventAggregator _events;
private Incident _selectedIncident;
public BindableCollection<Incident> Incidents { get; set; } = new BindableCollection<Incident>();
private string _text;
private string _incidentDescription;
private string _incidentName;
private string output = "";
public Incident SelectedIncident
{
get { return _selectedIncident; }
set
{
_selectedIncident = value;
NotifyOfPropertyChange(() => SelectedIncident);
NotifyOfPropertyChange(() => IncidentDescription);
// NotifyOfPropertyChange(() => HasOptions);
NotifyOfPropertyChange(() => Text);
NotifyOfPropertyChange(() => IncidentName);
}
}
public string IncidentDescription
{
get { return GetIncidentDescription(); }
set
{
_incidentDescription = value;
NotifyOfPropertyChange(() => IncidentDescription);
}
}
#region Constructor
public EditIncidentViewModel(IEventAggregator events)
{
_events = events;
var parser = new JsonParser();
parser.JsonLoadFile();
var list = parser.SortIncidentsByName();
foreach (var item in list)
{
Incidents.Add(new Incident
{
Name = item.Name,
Description = item.Description,
OtherDescription = item.OtherDescription,
Option = item.Option
});
}
}
#endregion
public string Text
{
get { return _text; }
set
{
_text = value;
NotifyOfPropertyChange(() => Text);
}
}
public string IncidentName
{
get {
if (SelectedIncident == null)
{
SelectedIncident = new Incident
{
Name = ""
};
}
return SelectedIncident.Name;
}
set {
_incidentName = value;
NotifyOfPropertyChange(() => IncidentName);
}
}
public string GetIncidentDescription()
{
if (SelectedIncident == null)
{
Incident inc = new Incident();
SelectedIncident = inc;
var nou = inc.Description;
SelectedIncident.Description = nou;
NotifyOfPropertyChange(() => SelectedIncident);
}
output = SelectedIncident.Description;
return output;
}
public void SaveIncident()
{
var newIncident = new Incident();
if (!string.IsNullOrWhiteSpace(_incidentName) || !string.IsNullOrWhiteSpace(_incidentDescription))
{
// Get SelectedIncident Name
newIncident.Name = _incidentName;
// Get SelectedIncident Description
newIncident.Description = _incidentDescription;
// Create a new Incident with the new properties
newIncident.OtherDescription = "dummy text here";
newIncident.Option = "";
// Incidents.Clear();
Incidents.Remove(SelectedIncident);
Incidents.Add(newIncident);
Incidents.Refresh();
// Save to file
string strResultJson = JsonConvert.SerializeObject(Incidents);
File.WriteAllText(Path.Combine(Environment.CurrentDirectory, "Data", "configuration.json"), strResultJson);
NotifyOfPropertyChange(() => IncidentDescription);
NotifyOfPropertyChange(() => IncidentName);
}
if (string.IsNullOrWhiteSpace(_incidentDescription) || _incidentDescription == IncidentDescription)
{
Incidents.Remove(SelectedIncident);
Text = $"Incident with name { SelectedIncident.Name } was deleted.";
_events.PublishOnUIThread(new StatusText(Text));
Incidents.Refresh();
// Save to file
string strResultJson = JsonConvert.SerializeObject(Incidents);
File.WriteAllText(Path.Combine(Environment.CurrentDirectory, "Data", "configuration.json"), strResultJson);
NotifyOfPropertyChange(() => IncidentDescription);
NotifyOfPropertyChange(() => IncidentName);
_events.BeginPublishOnUIThread(new BindableCollection<Incident>(Incidents));
}
}
}
DisplayIncidentView.xaml：
<ComboBox x:Name="Incidents" Height="40"
BorderBrush="#FFC7CC00" Foreground="#DD000000"
SelectedItem="{Binding SelectedIncident, Mode=OneWayToSource}"
DisplayMemberPath="Name"
materialDesign:HintAssist.Hint="Search" IsEditable="True" Style="{StaticResource MaterialDesignFloatingHintComboBox}"/>
答案 0 :(得分：0)
我忘了添加到DisplayIncidentViewModel构造函数中：
_events.Subscribe(this);