CODEWITHSUNDEEP
c#wpfdatagrid
Brent
Brent

Reputation: 209

Refresh a single item in a WPF ItemCollection

I have a DataGrid that is bound to some XML data.

When I make changes in the XML data, the DataGrid does not refresh to reflect those changes.

My "simple" way of fixing this is to call MyDataGrid.Items.Refresh() every time I make a change.

However, this is laggy and seems pretty inefficient.

How can I refresh just a single row, rather than the entire data grid? I have easy access to the DataGridRow as well as the XmlElement that is changed, but I just don't know what function to call.

Been stuck on this problem for 3-4 hours now and have tried dozens of solutions, but just can't get it to work.

Below is relevant code.

A) Defining the style.

    <!-- Field Value Style -->
    <local:FieldValueConverter x:Key="FieldValueConverter"/>
    <local:Node x:Key="Node"/>
    <Style x:Key="fieldValueStyle" TargetType="{x:Type TextBlock}">
        <Setter Property="Text" Value="{Binding ., Converter={StaticResource FieldValueConverter}}"/>
        <Setter Property="KeyboardNavigation.IsTabStop" Value="False"/>
        <Setter Property="Focusable" Value="False"/>
    </Style>

B) Defining the DataGrid

<DataGrid x:Name="FieldPanelDataGrid" DockPanel.Dock="Left"
        AutoGenerateColumns="False"
        DataContext="{Binding ElementName=ObjectPanelListBox, Path=SelectedItem}"
        ItemsSource="{Binding}"
        IsSynchronizedWithCurrentItem="True"
        IsReadOnly="True"
        CanUserResizeRows="False"
        CanUserResizeColumns="True"
        KeyboardNavigation.IsTabStop="False"
        Visibility="Visible"
        SelectionMode="Single">
    <DataGrid.Resources>
        <Style TargetType="DataGridRow">
            <EventSetter Event="MouseDoubleClick" Handler="FieldCell_MouseDoubleClick"/>
            <EventSetter Event="PreviewMouseLeftButtonDown" Handler="FieldCell_PreviewMouseLeftButonDown"></EventSetter>
            <EventSetter Event="PreviewKeyDown" Handler="FieldCell_PreviewKeyDown"></EventSetter>
        </Style>
    </DataGrid.Resources>
    <DataGrid.Columns>
        <DataGridTextColumn x:Name="FieldName" Header="Name" CanUserSort="False" ElementStyle="{StaticResource fieldNameStyle}"/>
        <DataGridTextColumn x:Name="FieldValue" Header="Value" Width="*" ElementStyle="{StaticResource fieldValueStyle}"/>
    </DataGrid.Columns>
</DataGrid>

Upvotes: 0

Views: 2475

Answers (1)

coder0815
coder0815

Reputation: 229

I suggest to use an ObservableCollection as ItemSource and the entries in the ObservableCollection have to implement INotifyPropertyChanged. Then you have the benefit if the rows change, the ObservableCollection will tell that your UI and it will update.

Example:

Your entry class:

public class MyXmlObject : INotifyPropertyChanged
{

    public event PropertyChangedEventHandler PropertyChanged;

    private string fieldName;

    public string FieldName
    {
        get { return fieldName; }
        set
        {
            fieldName = value;
            NotifyPropertyChanged("FieldName");
        }
    }

    NotifyPropertyChanged(string propertyName)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

Your code for the UserControl (ViewModel, Controller or Code behind):

public ObservableCollection<MyXmlObject> MyCollection { get; set; }

And as I mentioned in your xaml you simply bind the collection to the ItemsSource

<DataGrid ItemsSource="{Binding MyCollection}" .../>

Now only the items beeing changed get updated.

Upvotes: 1

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