<Page
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:editors="using:Syncfusion.UI.Xaml.Editors">
    <Grid>
        <editors:SfDropDownColorPalette x:Name="colorPalette" />
    </Grid>
</Page>

using Syncfusion.UI.Xaml.Editors;

public sealed partial class MainPage : Page
{
    public MainPage()
    {
        this.InitializeComponent();
        var colorPalette = new SfDropDownColorPalette();
        grid.Children.Add(colorPalette);
    }
}

<editors:SfDropDownColorPalette SelectedBrush="Yellow" x:Name="palette" />

// Get the selected color
var selectedBrush = palette.SelectedBrush as SolidColorBrush;
if (selectedBrush != null)
{
    Color selectedColor = selectedBrush.Color;
}

// Set a new color
palette.SelectedBrush = new SolidColorBrush(Colors.Red);

<editors:SfDropDownColorPalette 
    SelectedBrushChanged="Palette_SelectedBrushChanged"
    x:Name="palette" />

private void Palette_SelectedBrushChanged(object sender, SelectedBrushChangedEventArgs e)
{
    var oldBrush = e.OldBrush as SolidColorBrush;
    var newBrush = e.NewBrush as SolidColorBrush;
    
    // Apply color somewhere
    textBlock.Foreground = newBrush;
}

<editors:SfDropDownColorPalette 
    DropDownMode="Split"
    Command="{x:Bind ApplyColorCommand}"
    x:Name="palette" />

private ICommand applyColorCommand;
public ICommand ApplyColorCommand => applyColorCommand;

public void ApplyColorToSelectedText(object param)
{
    // Apply the currently selected color
    richTextBox.Document.Selection.CharacterFormat.BackgroundColor = 
        (palette.SelectedBrush as SolidColorBrush).Color;
}

<editors:SfDropDownColorPalette 
    DropDownPlacement="BottomEdgeAlignedRight"
    x:Name="palette" />

<editors:SfDropDownColorPalette 
    DropDownOpened="Palette_DropDownOpened"
    DropDownClosed="Palette_DropDownClosed"
    x:Name="palette" />

private void Palette_DropDownOpened(object sender, EventArgs e)
{
    // Palette opened
}

private void Palette_DropDownClosed(object sender, EventArgs e)
{
    // Palette closed
}