索引属性的 INotifyPropertyChanged

Question

So I have a class as follows:

public class Data : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;
    public object this[string field]
    {
        get => // gets the value
        set
        {
            // sets the value
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs("Item[]"));
        }
    }
}

and in my view :

<DataGrid
    AutoGenerateColumns="False"
    ItemsSource="{Binding Rows}">
    <DataGrid.Columns>
        <DataGridTextColumn Header="[some_field]" Binding="{Binding Path=[some_field]}" />
        <DataGridTextColumn Header="[some_other_field]" Binding="{Binding Path=[some_other_field]}" />
    </DataGrid.Columns>
</DataGrid>

This works fine but when PropertyChanged?.Invoke(this, new PropertyChangedEventArgs("Item[]")); happens, the DataGrid will fetch both the field "some_field" and the field "some_other_field" in Data and I haven't found a way to use the PropertyChanged that would make it refresh only the field that was updated.

I've tried with "Item[" + field + "]" , "[" + field + "]" , field but no luck. Is this something that is possible/supported or am I doing something wrong?

Answer 1

I think it's not possible, at least for WPF and dot NET Framework.

Suggestion/workaround: What if we added some read-only properties to the view model? Example:

public class Data : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;
    public object this[string field]
    {
        get => // gets the value
        set
        {
            // sets the value
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(field));
        }
    }

    public object some_field => this[nameof(some_field)];
    public object some_other_field=> this[nameof(some_other_field)];
}

And the XAML:

<DataGrid
    AutoGenerateColumns="False"
    ItemsSource="{Binding Rows}">
    <DataGrid.Columns>
        <DataGridTextColumn Header="[some_field]" Binding="{Binding Path=some_field}" />
        <DataGridTextColumn Header="[some_other_field]" Binding="{Binding Path=some_other_field}" />
    </DataGrid.Columns>
</DataGrid>

Doesn't really answer your question specifically, but it does provide a way to control how much of the view gets refreshed.