A simple solution for changing a DateTimerPicker background color

Imports System.Drawing
Imports System.Windows.Forms
Imports System.Security.Permissions
Imports System.Drawing.Drawing2D

Public Class RiverNilDateTimePicker
    Inherits DateTimePicker


    Private m_BlendColorDark As Color = Color.Blue
    Private m_BlendColorLight As Color = Color.Cyan
    Private Const WM_ERASEBKGND As Integer = &H14

    <securitypermission(securityaction.linkdemand,> _
    Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)
        If (m.Msg = WM_ERASEBKGND) Then
            Using g As Graphics = Graphics.FromHdc(m.WParam)
                Dim myFactors As Single() = New Single() {0.0F, 0.2F, 0.5F, 0.7F, 1.0F, 0.7F, 0.5F, 0.2F, 0.0F}
                Dim myPositions As Single() = New Single() {0.0F, 0.1F, 0.3F, 0.4F, 0.5F, 0.6F, 0.7F, 0.8F, 1.0F}
                Dim myBlend As New Drawing2D.Blend

                Dim rect As New Rectangle(New Point(1, 1), New Size(MyBase.ClientRectangle.Width - 19, MyBase.ClientRectangle.Height - 4))
                Using lgb As New Drawing2D.LinearGradientBrush(rect, Color.FromArgb(64, Me.m_BlendColorDark), Color.FromArgb(36, m_BlendColorLight), 90, False)
                    lgb.Blend = myBlend
                    g.FillRectangle(lgb, rect)
                End Using
            End Using
            m.Result = IntPtr.op_Explicit(1)
            Return
        End If
        MyBase.WndProc(m)
    End Sub

End Class