单击删除后如何更新列表框？ [英] How do I make my listbox update when I click delete ?
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问题描述
我有一个ListBox，当我选择一个项目然后单击删除按钮时，更改不会立即显示，直到我退出应用程序然后再次启动它。这些变化只有在我完成后才会反映出来。当我单击保存时，我的第二个窗口上的保存按钮也一样，我的列表框不会更新新添加的项目，直到我退出应用程序并再次返回到它，这时我会看到我添加的内容。
我尝试过：
我的第一个MainWindow的ViewModel
I have a ListBox which when I select an Item then click delete button the changes do not show immediately until I exit the app then start it up again. The changes reflect only when I have done that. Same goes for my saving button on the second window when I click save my listbox does not update the newly added Item until I exit the app and back to it again that is when I Will see what I have added.
What I have tried:
ViewModel for my first MainWindow
using GalaSoft.MvvmLight;
using GalaSoft.MvvmLight.Command;
using PhoneBook.View;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.IO;
using System.Linq;
namespace PhoneBook.ViewModel
{
class MainWindowViewModel : ViewModelBase
{
#region Constructor
public MainWindowViewModel()
{
ReadTextFile();
}
#endregion
#region Properties
public const string MyListPropertyName = "ListBox";
private ObservableCollection<string> _contactDetails = null;
public ObservableCollection<string> ContactDetails
{
get
{
return _contactDetails = _contactDetails ?? new ObservableCollection<string>();
}
set
{
if (_contactDetails == value)
{
return;
}
RaisePropertyChanged(MyListPropertyName);
_contactDetails = value;
RaisePropertyChanged(MyListPropertyName);
}
}
private string _selectedContact = null;
public string SelectedContact
{
get
{
return _selectedContact;
}
set
{
if (_selectedContact != null)
{
return;
}
_selectedContact = value;
RaisePropertyChanged();
}
}
#endregion
#region Method
string FileName = (@"C: \Users\StanleyM\Desktop\PhoneBook\PhoneBook\bin\Debug\Personal.text");
private void DeleteSelectedItemListBox()
{
var deletingNumber = ContactDetails.IndexOf(SelectedContact);
var allLines = File.ReadAllLines(FileName).ToList();
allLines.RemoveAt(deletingNumber);
File.WriteAllLines(FileName, allLines.ToArray());
RaisePropertyChanged(propertyName: "ListBox");
}
public void ReadTextFile()
{
string FileName = (@"C: \Users\StanleyM\Desktop\PhoneBook\PhoneBook\bin\Debug\Personal.text");
StreamReader streamReader = new StreamReader(FileName);
string line = "";
int Counter = 0;
while ((line = streamReader.ReadLine()) != null)
{
Counter++;
ContactDetails.Add(item: line);
}
RaisePropertyChanged("ListBox");
}
private void PopUpWindow()
{
AddEditView PopUp = new AddEditView();
PopUp.ShowDialog();
}
#endregion
#region RelayCommand
private RelayCommand _addCommand = null;
public RelayCommand AddCommand
{
get
{
return _addCommand = _addCommand ?? new RelayCommand(() => PopUpWindow());
}
}
private RelayCommand _deleteCommand = null;
public RelayCommand DeleteCommand
{
get
{
return _deleteCommand = _deleteCommand ?? new RelayCommand(() => DeleteSelectedItemListBox());
}
}
#endregion
}
}
< br $>
First View
First View
<Window x:Class="PhoneBook.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:PhoneBook"
mc:Ignorable="d"
Title="MainWindow" Height="350" Width="525">
<Window.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="/PhoneBook;component/Resource/Resource.xaml"></ResourceDictionary>
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Window.Resources>
<Border BorderThickness="5" BorderBrush="AliceBlue" Background="AntiqueWhite">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="25" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Label Grid.Row="0" Content="List of Clients" ></Label>
<Border Grid.Row="1" BorderThickness="5" Background="Black">
<ListBox SelectedItem="{Binding SelectedContact, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
ItemsSource="{Binding ContactDetails, UpdateSourceTrigger=PropertyChanged, NotifyOnSourceUpdated=True, Mode=TwoWay}"
Grid.Row="1">
</ListBox>
</Border>
<Button Grid.Row="1"
Grid.Column="1" Width="75"
Height="25" VerticalAlignment="Top"
Margin="100 10 0 0" HorizontalAlignment="Left"
Content="Add" Command="{Binding AddCommand}"></Button>
<Button Grid.Row="1"
Grid.Column="1"
Width="75" Height="25"
VerticalAlignment="Top"
Margin="100 60 0 0"
HorizontalAlignment="Left"
Content="Delete"
x:Name="Deletebtn" Click="Deletebtn_Click"
Command="{Binding DeleteCommand}"></Button>
</Grid>
</Border>
</Window>
ViewModel我的第二个窗口
ViewModel For my second window
using GalaSoft.MvvmLight;
using GalaSoft.MvvmLight.Command;
using PhoneBook.Class;
using PhoneBook.View;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
namespace PhoneBook.ViewModel
{
class AddEditViewModel : ViewModelBase
{
#region Construtors
public AddEditViewModel()
{
PopulateDropDown();
}
#endregion
#region Properties
private List<_Title> _titles = null;
public List<_Title> Titles
{
get
{
return _titles = _titles ?? new List<_Title>();
}
}
private _Title _selectedTitle = null;
public _Title SelectedTitle
{
get
{
return _selectedTitle;
}
set
{
_selectedTitle = value;
RaisePropertyChanged();
}
}
private List<_Gender> _genders = null;
public List<_Gender> Genders
{
get
{
return _genders = _genders ?? new List<_Gender>();
}
}
private _Gender _selectedGender = null;
public _Gender SelectedGender
{
get
{
return _selectedGender;
}
set
{
_selectedGender = value;
RaisePropertyChanged();
}
}
private string _firstName = null;
public string FirstName
{
get
{
return _firstName;
}
set
{
_firstName = value;
RaisePropertyChanged();
}
}
private string _lastName = null;
public string LastName
{
get
{
return _lastName;
}
set
{
_lastName = value;
RaisePropertyChanged();
}
}
private string _email = null;
public string Email
{
get
{
return _email;
}
set
{
_email = value;
RaisePropertyChanged();
}
}
private int _phoneNumber;
public int PhoneNumber
{
get
{
return _phoneNumber;
}
set
{
_phoneNumber = value;
RaisePropertyChanged();
}
}
#endregion
#region Method
private void CloseWindow()
{
AddEditView add = new AddEditView();
add.Close();
}
private void SaveDetails()
{
string Title = "";
string Gender = "";
int number = 0000000000;
if (SelectedTitle == null)
{
MessageBox.Show("Please select Title");
}
else if (FirstName == null)
{
MessageBox.Show("Please input First Name");
}
else if (LastName == null)
{
MessageBox.Show("Please input last Name");
}
else if (Email == null)
{
MessageBox.Show("Please input emaill");
}
else if (PhoneNumber != number )
{
MessageBox.Show("Only nunmbers allowed");
}
else if(SelectedGender == null)
{
MessageBox.Show("Please select Gender");
}
else if (true)
{
foreach (var item in Titles)
{
Title = item.Title = SelectedTitle.Title;
}
foreach (var item in Genders)
{
Gender = item.Gender = SelectedGender.Gender;
}
StringBuilder builder = new StringBuilder();
builder.AppendLine(string.Format("{0} {1} {2} {3} {4} {5}",Title, FirstName, LastName, Email, PhoneNumber, Gender));
File.AppendAllText("Personal.text", builder.ToString());
MessageBox.Show("Save", "Information");
}
}
private void PopulateDropDown()
{
Titles.Add(new _Title { Title = "Mr" });
Titles.Add(new _Title { Title = "Dr" });
Titles.Add(new _Title { Title = "Miss" });
Titles.Add(new _Title { Title = "Ms" });
Titles.Add(new _Title { Title = "Sir" });
Genders.Add(new _Gender { Gender = "Male" });
Genders.Add(new _Gender { Gender = "Female" });
}
#endregion
#region RelayCommands
private RelayCommand _saveCommand = null;
public RelayCommand SaveCommand
{
get
{
return _saveCommand = _saveCommand ?? new RelayCommand(() => SaveDetails());
}
}
private RelayCommand _cancelCommand = null;
public RelayCommand CancelCommand
{
get
{
return _cancelCommand = _cancelCommand ?? new RelayCommand(() => CloseWindow());
}
}
#endregion
}
}
秒查看
Second View
<Window x:Class="PhoneBook.View.AddEditView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:PhoneBook.View"
mc:Ignorable="d"
Title="AddEditView" Height="300" Width="300">
<Window.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="/PhoneBook;component/Resource/Resource.xaml"></ResourceDictionary>
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Window.Resources>
<Grid>
<Border BorderBrush="Black" BorderThickness="5" Background="AntiqueWhite">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="*"/>
<RowDefinition Height="*"/>
<RowDefinition Height="*"/>
<RowDefinition Height="*"/>
<RowDefinition Height="*"/>
<RowDefinition Height="*"/>
<RowDefinition Height="*"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Label Content="Title"></Label>
<ComboBox Grid.Row="0"
Grid.Column="0"
Text="{Binding Title, Mode=OneWay, UpdateSourceTrigger=PropertyChanged}"
ItemsSource="{Binding Titles, UpdateSourceTrigger=PropertyChanged}"
SelectedItem="{Binding SelectedTitle, UpdateSourceTrigger=PropertyChanged}"
DisplayMemberPath="Title"
Margin="3"
Width="100"
Height="25"/>
<Label Grid.Row="1"
Content="First name"
VerticalAlignment="Center" />
<TextBox Grid.Row="1"
Width="100"
Height="25"
Text="{Binding FirstName}"/>
<Label Grid.Row="2"
Content="Last name"
VerticalAlignment="Center" />
<TextBox Grid.Row="2"
Width="100"
Height="25"
Text="{Binding LastName}"/>
<Label Grid.Row="3"
Content="Email"
VerticalAlignment="Center" />
<TextBox Grid.Row="3"
Text="{Binding Email}"
Width="100"
Height="25"/>
<Label Grid.Row="4"
Content="Phone number"
VerticalAlignment="Center" />
<TextBox Grid.Row="4"
Width="100"
Height="25"
Text="{Binding PhoneNumber}"/>
<Label Grid.Row="5"
Content="Gender"></Label>
<ComboBox Grid.Row="5"
Width="100"
Height="25"
Text="{Binding Gender, Mode=OneWay, NotifyOnTargetUpdated=True}"
ItemsSource="{Binding Genders}"
DisplayMemberPath="Gender"
SelectedItem="{Binding SelectedGender}"/>
<Button Grid.Row="7"
Height="25"
Width="75"
Margin="100,0,0,0"
Content="Cancel"
Command="{Binding CancelCommand}"/>
<Button
Grid.Row="7"
Height="25"
Width="75"
Margin="0,0,100,0"
Content="Save"
Command="{Binding SaveCommand}"/>
</Grid>
</Border>
</Grid>
</Window>
推荐答案
我在上一个回答中介绍过，使用ObservableCollection，而不是列表< T>。在这里：如何从中删除选择的项目使用MVVM的列表框。 [ ^ ]
I covered that in my last answer, use anObservableCollection, not aList<T>. Here: How to delete seleted item from a listbox using MVVM.[^]
这篇关于单击删除后如何更新列表框？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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