CODEWITHSUNDEEP
c#wpfcombobox
ASHOK A
ASHOK A

Reputation: 2026

How to change combobox particular item color dynamically in wpf

<Grid x:Name="LayoutRoot">
    <ComboBox x:Name="com_ColorItems" Height="41" Margin="198,114,264,0" VerticalAlignment="Top" FontSize="13.333" FontWeight="Bold" Foreground="#FF3F7E24"/>
</Grid>

With above code I colored all items in the combobox green.

private void Window_Loaded(object sender, RoutedEventArgs e)
{
        for (int i = 0; i < 5; i++)
        {
            com_ColorItems.Items.Add(i);
        }
}

With above code I have filled five items into combobox. Now I like to change the color of the 3rd item (3) to "red" in code behind dynamically. How can I do that?

Upvotes: 7

Views: 13291

Answers (3)

Coden
Coden

Reputation: 2868

In addition to Mario Binders answer, here an example of such a converter:

public class ListToColoredComboboxItemsConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (value is IEnumerable<Measurement> measurements)
        {
            var comboBoxItems = new List<ComboBoxItem>(measurements.Count());
            foreach (var measurement in measurements)
            {
                var item = new ComboBoxItem();
                item.Content = measurement;
                if (!string.IsNullOrWhiteSpace(measurement.ErrorMessage))
                    item.Foreground = Brushes.Red;
                comboBoxItems.Add(item);
            }
            return comboBoxItems;
        }
        return null;
    }

    public object ConvertBack(object value, Type targetTypes, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

And probably you also want to convert the selected Item back to a value:

public class ComboBoxItemToItemConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return value;
    }

    public object ConvertBack(object value, Type targetTypes, object parameter, CultureInfo culture)
    {
        if (value is ComboBoxItem comboBoxItem)
        {
            return comboBoxItem.Content;
        }
        return null;
    }
}

Upvotes: 1

Mario Binder
Mario Binder

Reputation: 1623

First, try to bind your Source and avoid the directly access through code behind. And than you can use an Converter in your ItemSource Binding.

e.g.

ItemSource={Binding MyComboboxItems, Converter={StaticResource MyConverter}}

and in your Converter find you the 3rd Item and give them a different ForegroundColor

Upvotes: 2

Tibi
Tibi

Reputation: 3875

Instead of adding the actual value of i in the combobox, add a ComboBoxItem instead:

private void Window_Loaded(object sender, RoutedEventArgs e)
    {
        for (int i = 0; i < 5; i++)
        {
            ComboBoxItem item = new ComboBoxItem();

            if (i == 2) item.Foreground = Brushes.Blue;
            else item.Foreground = Brushes.Pink;

            item.Content = i.ToString();
            com_ColorItems.Items.Add(item);
        }
    }

If you want to modify the ComboBoxItem created with this method later, this is how you can do it:

var item = com_ColorItems.Items[2] as ComboBoxItem; // Convert from Object
if (item != null)                                   // Conversion succeeded 
{
    item.Foreground = Brushes.Tomato;
}

Upvotes: 11

Related Questions