I needed to have more dynamic content in a datagridview cell with a custom cell provided to us in VS 2005 and up
. Here is a class I came up with to accomplish this. Hope it helps somebody!
Sample Usage:
Sample usage:
Private Sub ConfigureGrid()
Me.gridQuestion.AutoGenerateColumns = False
Me.gridQuestion.Columns.Clear()
Dim column As New DataGridViewRichTextColumn()
column.ReadOnly = True
column.Width = Me.gridQuestion.ClientSize.Width
Me.gridQuestion.Columns.Add(column)
End Sub
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Imports System.Runtime.InteropServices
Imports System.Drawing.Printing
Imports VB6 = Microsoft.VisualBasic.Compatibility.VB6
Public Class DataGridViewRichTextCell
Inherits DataGridViewTextBoxCell
Private m_rtfTemplate As New RichTextBox
Protected Overrides Sub Paint(ByVal graphics As Graphics, _
ByVal clipBounds As Rectangle, ByVal cellBounds As Rectangle, _
ByVal rowIndex As Integer, ByVal cellState As DataGridViewElementStates, _
ByVal value As Object, ByVal formattedValue As Object, _
ByVal errorText As String, ByVal cellStyle As DataGridViewCellStyle, _
ByVal advancedBorderStyle As DataGridViewAdvancedBorderStyle, _
ByVal paintParts As DataGridViewPaintParts)
Dim brush As New SolidBrush(cellStyle.BackColor)
graphics.FillRectangle(brush, cellBounds)
brush.Dispose()
‘ Convert the text to Rtf, and then transfer to the Graphics object.
Me.PaintRtf(formattedValue, graphics, cellBounds, cellStyle.Font, cellStyle.BackColor)
‘ Paint the cell border after everything is done, or it will get
‘ overridden.
MyBase.PaintBorder(graphics, clipBounds, cellBounds, cellStyle, advancedBorderStyle)
End Sub
Private Function GetSelectionLink(ByVal charIndex As Integer) As Boolean
Const SCF_SELECTION As Int32 = &H1
Const CFE_LINK As Int32 = &H20
Dim cf As CHARFORMAT2_STRUCT = New CHARFORMAT2_STRUCT
cf.cbSize = CType(Marshal.SizeOf(cf), UInt32)
cf.szFaceName = New Char(32) {}
Dim wParam As IntPtr = New IntPtr(SCF_SELECTION)
Dim lParam As IntPtr = Marshal.AllocCoTaskMem(Marshal.SizeOf(cf))
Marshal.StructureToPtr(cf, lParam, False)
Dim res As IntPtr = SendMessage(m_rtfTemplate.Handle, EM_GETCHARFORMAT, wParam, lParam)
cf = CType(Marshal.PtrToStructure(lParam, GetType(CHARFORMAT2_STRUCT)), CHARFORMAT2_STRUCT)
Marshal.FreeCoTaskMem(lParam)
Return (cf.dwEffects And CFE_LINK)
End Function
Public Overrides ReadOnly Property DefaultNewRowValue() As Object
Get
‘ Use the current date and time as the default value.
Return String.Empty
End Get
End Property
#Region "PaintRtf"
<StructLayout(LayoutKind.Sequential)> _
Private Structure CHARFORMAT2_STRUCT
Public cbSize As UInt32
Public dwMask As UInt32
Public dwEffects As UInt32
Public yHeight As Int32
Public yOffset As Int32
Public crTextColor As Int32
Public bCharSet As Byte
Public bPitchAndFamily As Byte
<MarshalAs(UnmanagedType.ByValArray, SizeConst:=32)> _
Public szFaceName As Char()
Public wWeight As UInt16
Public sSpacing As UInt16
Public crBackColor As Integer
Public lcid As Integer
Public dwReserved As Integer
Public sStyle As Int16
Public wKerning As Int16
Public bUnderlineType As Byte
Public bAnimation As Byte
Public bRevAuthor As Byte
Public bReserved1 As Byte
End Structure
<StructLayout(LayoutKind.Sequential)> _
Private Structure RECT
Public Left As Integer
Public Top As Integer
Public Right As Integer
Public Bottom As Integer
End Structure
<StructLayout(LayoutKind.Sequential)> _
Private Structure CHARRANGE
Public cpMin As Integer ‘ First character of range (0 for start of doc)
Public cpMax As Integer ‘ Last character of range (-1 for end of doc)
End Structure
<StructLayout(LayoutKind.Sequential)> _
Private Structure FORMATRANGE
Public hdc As IntPtr ‘ Actual DC to draw on
Public hdcTarget As IntPtr ‘ Target DC for determining text formatting
Public rc As RECT ‘ Region of the DC to draw to (in twips)
Public rcPage As RECT ‘ Region of the whole DC (page size) (in twips)
Public chrg As CHARRANGE ‘ Range of text to draw (see above declaration)
End Structure
Private Const WM_USER As Int32 = &H400
Private Const EM_FORMATRANGE As Int32 = WM_USER + 57
Private Const EM_GETCHARFORMAT As Int32 = (WM_USER + 58)
Private Declare Function SendMessage Lib "USER32" Alias "SendMessageA" _
(ByVal hWnd As IntPtr, ByVal msg As Int32, ByVal wparam As IntPtr, _
ByVal lparam As IntPtr) As IntPtr
‘ Render the contents of the RichTextBox for printing
‘ Return the last character printed + 1 (printing start from this point for next page)
Private Sub PaintRtf(ByVal value As String, ByVal gr As Graphics, ByVal bounds As Rectangle, ByVal font As Font, ByVal backColor As Color)
If value Is Nothing Then
Exit Sub
End If
‘ Use an internal RichTextBox to format the text according to the
‘ business rules.
m_rtfTemplate.Font = font
m_rtfTemplate.WordWrap = False
m_rtfTemplate.Text = value
m_rtfTemplate.BackColor = backColor
m_rtfTemplate.DetectUrls = True
‘ Mark starting and ending character.
Dim cRange As CHARRANGE
cRange.cpMin = 0
cRange.cpMax = value.Length
‘ Calculate the area to render and print. The bounds need to
‘ be converted from pixels to twips (1/1440 of an inch).
Dim rectCell As New RECT
rectCell.Left = VB6.PixelsToTwipsX(bounds.Left) + 30
rectCell.Top = VB6.PixelsToTwipsY(bounds.Top) + 30
rectCell.Right = VB6.PixelsToTwipsX(bounds.Right)
rectCell.Bottom = VB6.PixelsToTwipsY(bounds.Bottom)
Dim rectPrint As RECT = rectCell
‘ Get the DC for the graphics object.
Dim hdc As IntPtr = gr.GetHdc()
‘ Initialize the FORMATRANGE structure for the EM_FORMATRANGE message.
Dim fmtRange As FORMATRANGE
fmtRange.chrg = cRange ‘ Indicate character from to character to
fmtRange.hdc = hdc ‘ Use the same DC for measuring and rendering
fmtRange.hdcTarget = hdc ‘ Point at printer hDC
fmtRange.rc = rectPrint ‘ Indicate the area on page to print
fmtRange.rcPage = rectCell ‘ Indicate whole size of page
Dim wParam As IntPtr = New IntPtr(1)
‘ Pass the FORMATRANGE structure to the lParam handle for the
‘ EM_FORMATRANGE message sent to the internal RichTextBox.
Dim lParam As IntPtr = Marshal.AllocCoTaskMem(Marshal.SizeOf(fmtRange))
Marshal.StructureToPtr(fmtRange, lParam, False)
‘ Tell the RichTextBox to paint on the DC.
Dim res As IntPtr = SendMessage(m_rtfTemplate.Handle, EM_FORMATRANGE, wParam, lParam)
‘ Free the block of memory allocated.
Marshal.FreeCoTaskMem(lParam)
‘ Release the device context handle obtained by a previous call.
gr.ReleaseHdc(hdc)
End Sub
#End Region
End Class
Public Class DataGridViewRichTextColumn
Inherits DataGridViewColumn
Public Sub New()
MyBase.New(New DataGridViewRichTextCell)
End Sub
Public Overrides Property CellTemplate() As DataGridViewCell
Get
Return MyBase.CellTemplate
End Get
Set(ByVal value As DataGridViewCell)
‘ Ensure that the cell used for the template is a CalendarCell.
If Not (value Is Nothing) AndAlso _
Not value.GetType().IsAssignableFrom(GetType(DataGridViewRichTextCell)) _
Then
Throw New InvalidCastException("Must be a DataGridViewRichTextCell")
End If
MyBase.CellTemplate = value
End Set
End Property
End Class