datagrid cells not updating when object properties in bindinglist change

Question

I have a WPF application with a datagrid who's ItemsSource is a BindingList. When I make changes to objects in the BindingList the datagrid is not being updated. How can I make sure the datagrid updates when I modify the object in the BindingList?

Here is the XAML:

<DataGrid CanUserAddRows="False" AutoGenerateColumns="False" HorizontalAlignment="Stretch" Name="dgLocalPlugins" VerticalAlignment="Stretch" SelectionMode="Single" AlternatingRowBackground="#CDEBEBEB" Margin="5,85,5,143" Width="Auto" SelectionChanged="dgLocalPlugins_SelectionChanged">
    <DataGrid.Columns>
        <DataGridCheckBoxColumn Header="Enabled" Binding="{Binding Path=Enabled}" Width="55" >
            <DataGridCheckBoxColumn.CellStyle>
                <Style>
                    <EventSetter Event="CheckBox.Checked" Handler="OnChecked"/>
                    <EventSetter Event="CheckBox.Unchecked" Handler="OnUnchecked"/>
                </Style>
            </DataGridCheckBoxColumn.CellStyle>
        </DataGridCheckBoxColumn>
        <DataGridTextColumn Header="Plugin" Binding="{Binding Path=Type}" IsReadOnly="True" Width="*" />
        <DataGridTextColumn Header="Status" Binding="{Binding Path=Status}" IsReadOnly="True" Width="*" />
    </DataGrid.Columns>
</DataGrid>

Here is the relevant code behind where I populate the BindingList:

private BindingList<PluginDescription> pluginList = new BindingList<PluginDescription>();

foreach (string path in osapdFiles)
{
    if (!string.IsNullOrEmpty(path))
    {
        PluginDescription desc = PluginHelper.Deserialize(path);
        pluginList.Add(desc);
    }
}

dgLocalPlugins.ItemsSource = pluginList;

Here is the PluginDescription class:

public class PluginDescription : INotifyPropertyChanged 
{
    private string _pluginName;
    public string Name
    {
        set
        {
            if (value != this._pluginName)
            {
                this._pluginName = value;
                NotifyPropertyChanged("Name");
            }
        }
        get { return _pluginName; }
    }

    private string _pluginType;
    public string Type
    {
        set
        {
            if (value != this._pluginType)
            {
                this._pluginType = value;
                NotifyPropertyChanged("Type");
            }
        }
        get { return _pluginType; }
    }

    private string _pluginVersion;
    public string Version
    {
        set
        {
            if (value != this._pluginVersion)
            {
                this._pluginVersion = value;
                NotifyPropertyChanged("Version");
            }
        }
        get { return _pluginVersion; }
    }

    private string _pluginAuthor;
    public string Author
    {
        set
        {
            if (value != this._pluginAuthor)
            {
                this._pluginAuthor = value;
                NotifyPropertyChanged("Author");
            }
        }
        get { return _pluginAuthor; }
    }

    private string _wikiUrl;
    public string WikiUrl
    {
        set
        {
            if (value != this._wikiUrl)
            {
                this._wikiUrl = value;
                NotifyPropertyChanged("Wiki");
            }
        }
        get { return _wikiUrl; }
    }

    private string _description;
    public string Description
    {
        set
        {
            if (value != this._description)
            {
                this._description = value;
                NotifyPropertyChanged("Description");
            }
        }
        get { return _description; }
    }

    private string _status;
    public string Status
    {
        set
        {
            if (value != this._status)
            {
                this._status = value;
                NotifyPropertyChanged("Statua");
            }
        }
        get { return _status; }
    }

    private bool _enabled;
    public bool Enabled
    {
        set
        {
            if (value != this._enabled)
            {
                this._enabled = value;
                NotifyPropertyChanged("Enabled");
            }
        }
        get { return _enabled; }
    }

    private string _upgrade;
    public string Upgrade
    {
        set
        {
            if (value != this._upgrade)
            {
                this._upgrade = value;
                NotifyPropertyChanged("Upgrade");
            }
        }
        get { return _upgrade; }
    }

    private string _path;
    public string Path
    {
        set
        {
            if (value != this._path)
            {
                this._path = value;
                NotifyPropertyChanged("Path");
            }
        }
        get { return _path; }
    }

    public event PropertyChangedEventHandler PropertyChanged;
    private void NotifyPropertyChanged(String info)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(info));
        }
    }

}

Now, when I modify a property of one of the PluginDescription objects the DataGrid is not being updated. I thought implementing the INotifyPropertyChange interface on the PluginDescription class would be all I need. Do I need to do something else?

Answer 1

You already found the cause of the error. But to avoid such issues in the future I suggest using Lambda Expressions where acceptable.

Note that it brings some performance penalty though, somebody described it here: http://blog.quantumbitdesigns.com/2010/01/26/mvvm-lambda-vs-inotifypropertychanged-vs-dependencyobject/

But property changed notifications are usually so rarely triggered that this is not really a problem. However it depends on your usage ...

Answer 2

The PropertyChanged event must be supplied with the precise name of your property. In your code, you have some mismatches: the WikiUrl property raises a PropertyChanged event with "Wiki", and the Status property with "Statua". Try fixing those first.

If it still doesn’t work, could you please specify which properties you’re trying to change?