DataGridView With Transparent Background Or Background Image

[dunfiddlin]

It is not possible to make a DataGridView truly transparent so this class simulates transparency by copying the parent background. Making use of this process also makes it possible to add a background image directly to the DataGridView.

Additional Properties:

DGVHasTransparentBackground Boolean: sets transparency
DGVBackgroundImage Image: set to Nothing to return to

Known Issues:

Double buffering is recommended for all systems, essential on slower systems.
Scrolling causes a bit of a graphic 'kick' both with and without scrollbars.

Imports System.ComponentModel
 
Public Class TransparentDGV
 
    ' original by Deumber of Stack Overflow Forum
    ' adapted by IanRyder of VBForums
    ' corrections, improvements and additional features by dunfiddlin of VBForums
 
    Inherits DataGridView
 
    Private _DGVHasTransparentBackground As Boolean
    Private _DGVBackgroundImage As Image
 
    <Category("Transparency"), _
      Description("Select whether the control has a Transparent Background.")> Public Property DGVHasTransparentBackground As Boolean
        Get
            Return _DGVHasTransparentBackground
        End Get
        Set(value As Boolean)
            _DGVHasTransparentBackground = value
            If _DGVHasTransparentBackground Then
                SetTransparentProperties(True)
            Else
                SetTransparentProperties(False)
            End If
        End Set
    End Property
 
    Public Property DGVBackgroundImage As Image
        Get
            Return _DGVBackgroundImage
        End Get
        Set(value As Image)
            _DGVBackgroundImage = value
            If Not _DGVBackgroundImage Is Nothing Then
                SetTransparentProperties(True)
                _DGVHasTransparentBackground = True
            ElseIf _DGVHasTransparentBackground Then
                SetTransparentProperties(True)
            Else
                SetTransparentProperties(False)
            End If
        End Set
    End Property
 
    Public Sub New()
        Me.BorderStyle = Windows.Forms.BorderStyle.None
    End Sub
 
    Private Sub SetTransparentProperties(ByRef SetAsTransparent As Boolean)
        If SetAsTransparent Then
            MyBase.DoubleBuffered = True
            MyBase.EnableHeadersVisualStyles = False
        Else
            MyBase.DoubleBuffered = False
            MyBase.EnableHeadersVisualStyles = True
            MyBase.ColumnHeadersDefaultCellStyle.BackColor = SystemColors.Control
            MyBase.RowHeadersDefaultCellStyle.BackColor = SystemColors.Control
            SetCellStyle(Color.White)
        End If
    End Sub
 
    Protected Overrides Sub PaintBackground(graphics As System.Drawing.Graphics, clipBounds As System.Drawing.Rectangle, gridBounds As System.Drawing.Rectangle)
        MyBase.PaintBackground(graphics, clipBounds, gridBounds)
        Dim rectSource As New Rectangle(MyBase.Location, MyBase.Size)
        Dim rectDest As New Rectangle(0, 0, rectSource.Width, rectSource.Height)
 
        If _DGVHasTransparentBackground Then
            If Not IsNothing(MyBase.Parent.BackgroundImage) Then
                Dim pb As New PictureBox
                pb.Width = Parent.ClientRectangle.Width
                pb.Height = Parent.ClientRectangle.Height
                pb.BackgroundImageLayout = Parent.BackgroundImageLayout
                pb.BackgroundImage = Parent.BackgroundImage
 
                Dim b As New Bitmap(rectSource.Width, rectSource.Height)
                Dim bp As New Bitmap(Parent.ClientRectangle.Width, Parent.ClientRectangle.Height)
                pb.DrawToBitmap(bp, New Rectangle(0, 0, bp.Width, bp.Height))
                graphics.FromImage(b).DrawImage(bp, rectDest, rectSource, GraphicsUnit.Pixel)
                graphics.DrawImage(b, rectDest)
            Else
                Dim myBrush As New SolidBrush(MyBase.Parent.BackColor)
                Dim rectDest1 As New Region(New Rectangle(0, 0, MyBase.Width, MyBase.Height))
                graphics.FillRegion(myBrush, rectDest1)
            End If
        End If
 
        If Not _DGVBackgroundImage Is Nothing Then
            graphics.DrawImage(_DGVBackgroundImage, rectDest)
        End If
    End Sub
 
    Protected Overrides Sub OnColumnAdded(e As System.Windows.Forms.DataGridViewColumnEventArgs)
        MyBase.OnColumnAdded(e)
        If _DGVHasTransparentBackground Then
            SetCellStyle(Color.White)
        End If
    End Sub
 
    Private Sub SetCellStyle(ByVal cellColour As Color)
        For Each col As DataGridViewColumn In MyBase.Columns
            col.DefaultCellStyle.BackColor = cellColour
            col.DefaultCellStyle.SelectionBackColor = cellColour
        Next
    End Sub
 
    Private Sub myControl_ParentChanged(ByVal sender As Object, ByVal e As EventArgs) Handles Me.ParentChanged
        AddHandler Parent.Resize, AddressOf Parent_Resize
    End Sub
 
    Sub Parent_Resize(ByVal sender As Object, ByVal e As EventArgs)
        Me.Refresh()
    End Sub
 
    Protected Overrides Sub OnScroll(e As System.Windows.Forms.ScrollEventArgs)
        MyBase.OnScroll(e)
        Me.Refresh()
    End Sub
End Class