Updating one element of a bound Observable collection

问题

I have an observable collection with a custom class called songInfo inside.
It is bound to a ListView. Here is the code for the binding:

C#:

var songData = new ObservableCollection<songInfo>();

public ObservableCollection<songInfo> _songData
{ 
    get 
    { 
        return songData; 
    } 
}

public class songInfo
{
    public string Title { get; set; }
    public string Artist { get; set; }
    public string Album { get; set; }
    public string Location { get; set; }
    public string Ext { get; set; }
    public bool isSongPlaying { get; set; }
}

XAML:

<Window x:Class="Genesis.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Genesis (Alpha)" Height="897" Width="882" Loaded="Window_Loaded"
    DataContext="{Binding RelativeSource={RelativeSource Self}}" Name="Genesis">

    <ListView Margin="12,39,0,0" Name="Library" DataContext="{Binding}" ItemsSource="{Binding _songData}" Height="681" VerticalAlignment="Top" MouseDoubleClick="Library_MouseDoubleClick"  ContextMenu="{StaticResource MyContextMenu}" AlternationCount="2" Background="AliceBlue" HorizontalAlignment="Left" Width="846">
        <ListView.View>
            <GridView x:Name="gvLibrary">
                <GridViewColumn Width="20" Header="hi" DisplayMemberBinding="{Binding isSongPlaying}" x:Name="gvColumnPlaying" />
                <GridViewColumn Width="220" Header="Title" DisplayMemberBinding="{Binding Title}" x:Name="gvColumnTitle" />
                <GridViewColumn Width="180" Header="Artist" DisplayMemberBinding="{Binding Artist}" x:Name="gvColumnArtist" />
                <GridViewColumn Width="180" Header="Album" DisplayMemberBinding="{Binding Album}" x:Name="gvColumnAlbum" />
                <GridViewColumn Width="180" Header="Location" DisplayMemberBinding="{Binding Location}" x:Name="gvColumnLocation" />
                <GridViewColumn Width="80" Header="File Type" DisplayMemberBinding="{Binding Ext}" x:Name="gvColumnFileType" />
            </GridView>
        </ListView.View>
    </ListView>

The songInfo is populated at other points in my code. When elements are added or removed, the ListView is updated. However, there are points when I simply change just songInfo.Ext or songInfo.Location, etc. I found a convoluted way to do this and update, but I had to remove the element and re-add it:

songInfo temp = songData[playing_song_index];
songData.RemoveAt(playing_song_index);
songData.Insert(playing_song_index, new songInfo()
{
    Title = temp.Title,
    Artist = temp.Artist,
    Album = temp.Album,
    Location = temp.Location,
    Ext = temp.Ext,
    isSongPlaying = true
});

That changes isSongPlaying to true.

Is there an easier way to just update one "column" of the GridView?

回答1:

Your songInfo class needs to implement INotifyPropertyChanged.

If you implement this interface properly, then changes to members of the class will automatically get reflected within the user interface via the binding.

回答2:

If songInfo doesn't use INotifyPropertyChanged, then what you are doing will work. You could clean it up a bit by:

var mySong = songData.//get your song
int index = songData.IndexOf( mySong );
songData.Remove( mySong  );
songData.Insert( index, mySong );

来源：https://stackoverflow.com/questions/14532609/updating-one-element-of-a-bound-observable-collection

标签

listview

gridview

binding

observablecollection