From predefined color name in the Colors class

   
  
<Window x:Class="WpfApplication1.SolidColorBrushExample"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  Title="SolidColorBrush Example" Height="415" Width="270">
  <Canvas Margin="5">
    <StackPanel>
      <TextBlock Margin="0,10,0,5">
        From predefined color name in the Colors class:
      </TextBlock>
      <Rectangle x:Name="rect2" Width="100" Height="30"
        Stroke="Blue" />


    </StackPanel>
  </Canvas>
</Window>

//File:Window.xaml.cs
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Shapes;


namespace WpfApplication1
{
    public partial class SolidColorBrushExample : Window
    {
        public SolidColorBrushExample()
        {
            InitializeComponent();
            SolidColorBrush brush = new SolidColorBrush();

            // From predefined color name in the Colors class: 
            brush = new SolidColorBrush(Colors.Green);
            rect2.Fill = brush;

        }

    }
}