Fill a Rectangle with LinearGradientBrush

   
 
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Text;
using System.Windows.Forms;

public class Form1 : Form {

    protected override void OnPaint(PaintEventArgs e) {
        Graphics g = e.Graphics;

        LinearGradientBrush lgb = new LinearGradientBrush(
                                             new Point(0, 0),
                                             new Point(50, 10),
                                             Color.White,
                                             Color.Black);
        g.FillRectangle(lgb, this.ClientRectangle);
        lgb.Dispose();
    }
    public static void Main() {
        Application.Run(new Form1());
    }
}