Hi!

I hope jasmine can read this because she had my identical problem.

I solved it in this way and it seems to work fine, even if the re-painting
is "not-so-fast"

What do you need
- Obtain the VScrollBar for calculating the effective DataGrid client area.
- Trap the Scroll event: datagrid does not provide it, but the VScrollBar
do.
- Define a list of color/rows to color
- Do a row-painting each time
- the DataGrid scrolls
- the DataGrid paints (i.e.: the column size is changed by the user)
- a new back color is defined

Here is my code (sorry it is a little long).
I done a class that "extends" the DataGrid
In this code I havn't defined a ForeColor for cells, but as you could see is
really simple to improve it, maybe as a couple of Back-and-Fore colors
value.
Also this show how to color a full row: again is really simple to change it
for let it paint a single cell.

Every suggestion on this code is welcome.

-------- You can cut and paste in a new .vb file -------

Imports System.Data
Imports System

' Needed by DatagridExtender
Imports System.Windows.Forms
Imports System.Reflection
Imports System.Drawing


Public Class Form1
Inherits System.Windows.Forms.Form

#Region " Codice generato da Progettazione Windows Form "

Public Sub New()
MyBase.New()
InitializeComponent()
End Sub

Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
MyBase.Dispose(disposing)
End Sub

Friend WithEvents DataGrid1 As System.Windows.Forms.DataGrid

Private Sub InitializeComponent()
Me.DataGrid1 = New System.Windows.Forms.DataGrid
'
'DataGrid1
'
Me.DataGrid1.Location = New System.Drawing.Point(16, 24)
Me.DataGrid1.Size = New System.Drawing.Size(208, 144)
Me.DataGrid1.Text = "DataGrid1"
'
'Form1
'
Me.Controls.Add(Me.DataGrid1)
Me.Text = "Form1"

End Sub

#End Region

Dim dgx As DataGridExtender


Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
Dim t As New DataTable
dgx = New DataGridExtender(DataGrid1)
t.Columns.Add("Column1")
t.Columns.Add("Column2")
For i As Int32 = 1 To 20
t.Rows.Add(New Object() {"This is the long line #" +
i.ToString})

If i Mod 3 = 0 Then
dgx.SetRowBackColor(i, Drawing.Color.Red)
End If

Next i
DataGrid1.DataSource = t
End Sub
End Class



Public Class DataGridExtender

Private blnCEditActive As Boolean
Private objCTextBox As TextBox
Private WithEvents objCGrid As DataGrid
Private WithEvents objCVScrollBar As VScrollBar
Private objCRowBackColors As New System.Collections.Hashtable

Public Sub New(ByVal grid As DataGrid)
objCGrid = grid
objCVScrollBar = DirectCast(grid.GetType().GetField("m_sbVert",
_

BindingFlags.NonPublic Or _

BindingFlags.GetField Or _

BindingFlags.Instance).GetValue(grid), VScrollBar)

'hsb = (HScrollBar)grid.GetType().GetField("m_sbHorz",
BindingFlags.NonPublic|BindingFlags.GetField|BindingFlags.Instance).GetValue
(grid);
End Sub


Public Sub SetRowBackColor(ByVal rowIndex As Int32, ByVal
rowBackColor As Drawing.Color)
If objCRowBackColors.Contains(rowIndex) Then
objCRowBackColors.Remove(rowIndex)
End If
If (rowBackColor.ToArgb <> Drawing.SystemColors.Window.ToArgb)
Then
objCRowBackColors.Add(rowIndex, rowBackColor)
PaintRows()
End If
End Sub

Private Sub PaintRows()
Dim dt As DataTable = DirectCast(objCGrid.DataSource, DataTable)
If (Not objCGrid.DataSource Is Nothing) AndAlso _
(dt.Rows.Count > 0) AndAlso _
(objCRowBackColors.Count > 0) Then
Dim intLLeft As Int32 = objCGrid.GetCellBounds(0, 0).Left
Dim ht As DataGrid.HitTestInfo = objCGrid.HitTest(1,
intLLeft)
Dim cw As Int32
Dim maxw As Int32 = objCGrid.ClientSize.Width - intLLeft -
objCVScrollBar.Width
For i As Int32 = ht.Row To ht.Row + objCGrid.VisibleRowCount
If objCRowBackColors.Contains(i) Then
Dim g As Drawing.Graphics = objCGrid.CreateGraphics
Dim r As Rectangle
cw = 0
For col As Int32 = 0 To dt.Columns.Count - 1
r = objCGrid.GetCellBounds(i, col)

' this is for avoid painting over the
' scrollbox in the bottom-right
cw += r.Width
If cw > maxw Then
r.Width -= (cw - maxw)
End If
g.FillRectangle(New
SolidBrush(DirectCast(objCRowBackColors.Item(i), _
Color)), r)

g.DrawString(dt.Rows(i).Item(col).ToString, _
objCGrid.Font, _
New SolidBrush(objCGrid.ForeColor),
_
New RectangleF(r.X + 2, r.Y + 2,
r.Width, r.Height))
Next
End If
Next
End If
End Sub



Private Sub objCVScrollBar_ValueChanged(ByVal sender As Object,
ByVal e As System.EventArgs) Handles objCVScrollBar.ValueChanged
PaintRows()
End Sub

Private Sub objCGrid_Paint(ByVal sender As Object, ByVal e As
System.Windows.Forms.PaintEventArgs) Handles objCGrid.Paint
PaintRows()
End Sub

End Class



--------------------------------------------------------

--
Math Parser : http://www.neodatatype.net

"Zanna" <(E-Mail Removed)> wrote in message
news:7Fp2c.7125$(E-Mail Removed)...



> Public Class DataGridExtender
>
> Private blnCEditActive As Boolean
> Private objCTextBox As TextBox

Ok, the TextBox does nothing

It was a test-object: in the same way you paint a cell you can overlaps
objects adding them to the DataGrid.Controls and inflating the Rectangle by
1pixel for side (Rectange.Inflate(1,1)).

The rectangle have to be inflated *before* to assigning it to
Control.Bounds.

That's all

--
Math Parser : http://www.neodatatype.net

Thank You SOOO Much Zanna!!!!
Your code works very well and it was very easy to
understand!!!!


>-----Original Message-----
>Hi!
>
>I hope jasmine can read this because she had my identical
problem.
>
>I solved it in this way and it seems to work fine, even
if the re-painting
>is "not-so-fast"
>
>What do you need
>- Obtain the VScrollBar for calculating the effective
DataGrid client area.
>- Trap the Scroll event: datagrid does not provide it,
but the VScrollBar
>do.
>- Define a list of color/rows to color
>- Do a row-painting each time
> - the DataGrid scrolls
> - the DataGrid paints (i.e.: the column size is
changed by the user)
> - a new back color is defined
>
>Here is my code (sorry it is a little long).
>I done a class that "extends" the DataGrid
>In this code I havn't defined a ForeColor for cells, but
as you could see is
>really simple to improve it, maybe as a couple of Back-
and-Fore colors
>value.
>Also this show how to color a full row: again is really
simple to change it
>for let it paint a single cell.
>
>Every suggestion on this code is welcome.
>
>-------- You can cut and paste in a new .vb file -------
>
>Imports System.Data
>Imports System
>
>' Needed by DatagridExtender
>Imports System.Windows.Forms
>Imports System.Reflection
>Imports System.Drawing
>
>
>Public Class Form1
> Inherits System.Windows.Forms.Form
>
>#Region " Codice generato da Progettazione Windows Form "
>
> Public Sub New()
> MyBase.New()
> InitializeComponent()
> End Sub
>
> Protected Overloads Overrides Sub Dispose(ByVal
disposing As Boolean)
> MyBase.Dispose(disposing)
> End Sub
>
> Friend WithEvents DataGrid1 As
System.Windows.Forms.DataGrid
>
> Private Sub InitializeComponent()
> Me.DataGrid1 = New System.Windows.Forms.DataGrid
> '
> 'DataGrid1
> '
> Me.DataGrid1.Location = New System.Drawing.Point
(16, 24)
> Me.DataGrid1.Size = New System.Drawing.Size(208,
144)
> Me.DataGrid1.Text = "DataGrid1"
> '
> 'Form1
> '
> Me.Controls.Add(Me.DataGrid1)
> Me.Text = "Form1"
>
> End Sub
>
>#End Region
>
> Dim dgx As DataGridExtender
>
>
> Private Sub Form1_Load(ByVal sender As System.Object,
ByVal e As
>System.EventArgs) Handles MyBase.Load
> Dim t As New DataTable
> dgx = New DataGridExtender(DataGrid1)
> t.Columns.Add("Column1")
> t.Columns.Add("Column2")
> For i As Int32 = 1 To 20
> t.Rows.Add(New Object() {"This is the long
line #" +
>i.ToString})
>
> If i Mod 3 = 0 Then
> dgx.SetRowBackColor(i, Drawing.Color.Red)
> End If
>
> Next i
> DataGrid1.DataSource = t
> End Sub
>End Class
>
>
>
> Public Class DataGridExtender
>
> Private blnCEditActive As Boolean
> Private objCTextBox As TextBox
> Private WithEvents objCGrid As DataGrid
> Private WithEvents objCVScrollBar As VScrollBar
> Private objCRowBackColors As New
System.Collections.Hashtable
>
> Public Sub New(ByVal grid As DataGrid)
> objCGrid = grid
> objCVScrollBar = DirectCast(grid.GetType
().GetField("m_sbVert",
>_
>
>BindingFlags.NonPublic Or _
>
>BindingFlags.GetField Or _
>
>BindingFlags.Instance).GetValue(grid), VScrollBar)
>
> 'hsb = (HScrollBar)grid.GetType().GetField
("m_sbHorz",
>BindingFlags.NonPublic|BindingFlags.GetField|BindingFlags.
Instance).GetValue
>(grid);
> End Sub
>
>
> Public Sub SetRowBackColor(ByVal rowIndex As
Int32, ByVal
>rowBackColor As Drawing.Color)
> If objCRowBackColors.Contains(rowIndex) Then
> objCRowBackColors.Remove(rowIndex)
> End If
> If (rowBackColor.ToArgb <>
Drawing.SystemColors.Window.ToArgb)
>Then
> objCRowBackColors.Add(rowIndex,
rowBackColor)
> PaintRows()
> End If
> End Sub
>
> Private Sub PaintRows()
> Dim dt As DataTable = DirectCast
(objCGrid.DataSource, DataTable)
> If (Not objCGrid.DataSource Is Nothing)
AndAlso _
> (dt.Rows.Count > 0) AndAlso _
> (objCRowBackColors.Count > 0) Then
> Dim intLLeft As Int32 =
objCGrid.GetCellBounds(0, 0).Left
> Dim ht As DataGrid.HitTestInfo =
objCGrid.HitTest(1,
>intLLeft)
> Dim cw As Int32
> Dim maxw As Int32 =
objCGrid.ClientSize.Width - intLLeft -
>objCVScrollBar.Width
> For i As Int32 = ht.Row To ht.Row +
objCGrid.VisibleRowCount
> If objCRowBackColors.Contains(i) Then
> Dim g As Drawing.Graphics =
objCGrid.CreateGraphics
> Dim r As Rectangle
> cw = 0
> For col As Int32 = 0 To
dt.Columns.Count - 1
> r = objCGrid.GetCellBounds(i,
col)
>
> ' this is for avoid painting
over the
> ' scrollbox in the bottom-
right
> cw += r.Width
> If cw > maxw Then
> r.Width -= (cw - maxw)
> End If
> g.FillRectangle(New
>SolidBrush(DirectCast(objCRowBackColors.Item(i), _
>
Color)), r)
>
> g.DrawString(dt.Rows(i).Item
(col).ToString, _
> objCGrid.Font, _
> New SolidBrush
(objCGrid.ForeColor),
>_
> New RectangleF
(r.X + 2, r.Y + 2,
>r.Width, r.Height))
> Next
> End If
> Next
> End If
> End Sub
>
>
>
> Private Sub objCVScrollBar_ValueChanged(ByVal
sender As Object,
>ByVal e As System.EventArgs) Handles
objCVScrollBar.ValueChanged
> PaintRows()
> End Sub
>
> Private Sub objCGrid_Paint(ByVal sender As
Object, ByVal e As
>System.Windows.Forms.PaintEventArgs) Handles
objCGrid.Paint
> PaintRows()
> End Sub
>
> End Class
>
>
>
>--------------------------------------------------------
>
>--
>Math Parser : http://www.neodatatype.net
>
>
>
>
>.
>

Jasmine wrote:
> Thank You SOOO Much Zanna!!!!
> Your code works very well and it was very easy to
> understand!!!!

Happy to be of some help

After this post I changed the code a little because it has a bug when
you scroll the grid horizontally.

You need yo trap also the HScrollBar_ValueChanged and the
DataGrid_CurrentCellChanged.

Also you need to change the PaintRows routine as this:

You will see I changed the RowColor to CellFormat that is simply

Private Structure CellFormat
Public Back As Color
Public Fore As Color
Public Sub New(ByVal backColor As Color, ByVal foreColor As
Color)
Back = backColor
Fore = foreColor
End Sub
End Structure


You'll need to change it into the SetRowBackColor sub (maybe you'll want
to rename it to SetRowColors)


Private Sub PaintRows()
If (Not MyBase.DataTable Is Nothing) AndAlso _
(objCRowColors.Count > 0) AndAlso _
(MyBase.DataTable.Rows.Count > 0) Then

Dim intLFirstRowIdx As Int32 = Me.FirstVisibleRow
Dim intLFirstColIdx As Int32 = Me.FirstVisibleColumn

Dim cw As Int32
Dim cf As CellFormat
Dim clip_rect As Rectangle

clip_rect = New Rectangle(intCRowHeaderWidth + 2, _
1, _
objCGrid.ClientSize.Width -
intCRowHeaderWidth - objCVScrollBar.Width - 2, _
objCGrid.ClientSize.Height)

Dim g As Drawing.Graphics = objCGrid.CreateGraphics
g.Clip = New Region(clip_rect)

For i As Int32 = intLFirstRowIdx To intLFirstRowIdx +
objCGrid.VisibleRowCount - 1
If objCRowColors.Contains(i) Then

Dim render_rect As Rectangle

For col As Int32 = intLFirstColIdx To
intLFirstColIdx + objCGrid.VisibleColumnCount - 1
render_rect = objCGrid.GetCellBounds(i,
col)

cf = DirectCast(objCRowColors.Item(i),
CellFormat)

g.FillRectangle(New
SolidBrush(cf.Back), render_rect)


g.DrawString(MyBase.DataTable.Rows(i).Item(col).ToString, _
objCGrid.Font, _
New SolidBrush(cf.Fore), _
New
RectangleF(render_rect.X + 2, _

render_rect.Y + 2, _

render_rect.Width - 4, _

render_rect.Height - 4))

Next
End If
Next
End If
End Sub

Public ReadOnly Property FirstVisibleRow() As Int32
Get
Return
DirectCast(objCGrid.GetType.GetField("m_irowVisibleFirst", _

Reflection.BindingFlags.NonPublic Or _
Reflection.BindingFlags.GetField
Or _

Reflection.BindingFlags.Instance)
).GetValue(objCGrid), _
Int32)
End Get
End Property

Public ReadOnly Property FirstVisibleColumn() As Int32
Get
Return objCGrid.FirstVisibleColumn
End Get
End Property

Zanna wrote:

> After this post I changed the code a little because it has a bug when
> you scroll the grid horizontally.

Oh, the intCRowHeaderWidth is (I think) always 20, but you can get it
via reflection asking for "m_kcxDefaultRowHdrWidth" that is a
BindingFlags.Static and not BindingBlag.Instance.

See youuu

You're my lifesaver, Zanna!!
I've noticed about the horizontal scrollbar and was trying
to figure it out myself. And then you post the new code
just right on time!! Thank you for your rapid response!!!
THANK YOU THANK YOU THANK YOU!!!


>-----Original Message-----
>Zanna wrote:
>
>> After this post I changed the code a little because it
has a bug when
>> you scroll the grid horizontally.
>
>Oh, the intCRowHeaderWidth is (I think) always 20, but
you can get it
>via reflection asking for "m_kcxDefaultRowHdrWidth" that
is a
>BindingFlags.Static and not BindingBlag.Instance.
>
>See youuu
>
>
>
>
>.
>

Hi Zanna,

Sorry It's me Jasmine again!
After testing out your code, there's an error that I
couldn't fix. My code always stopped at this line for some
reason:
cf = DirectCast(objCRowColors.Item(i), CellFormat)

The problem might be the CellFormat structure. I have
never used a structure before. Where should I place the
strucure??

Once again, Thank you so much!!

Jasmine

>-----Original Message-----
>Zanna wrote:
>
>> After this post I changed the code a little because it
has a bug when
>> you scroll the grid horizontally.
>
>Oh, the intCRowHeaderWidth is (I think) always 20, but
you can get it
>via reflection asking for "m_kcxDefaultRowHdrWidth" that
is a
>BindingFlags.Static and not BindingBlag.Instance.
>
>See youuu
>
>
>
>
>.
>

Jasmine wrote:
> Hi Zanna,
>
> Sorry It's me Jasmine again!
> After testing out your code, there's an error that I
> couldn't fix. My code always stopped at this line for some
> reason:
> cf = DirectCast(objCRowColors.Item(i), CellFormat)
>
> The problem might be the CellFormat structure.

Yes, this is a structure where I store fore/back colors:

I changed its name to a more understandable

Private Structure CellColorInfo
Public Back As Color
Public Fore As Color
Public Sub New(ByVal backColor As Color, ByVal foreColor As
Color)
Back = backColor
Fore = foreColor
End Sub
End Structure

Also, for the previous "m_kcxDefaultRowHdrWidth" tips, if you use it be
sure you use "v_cxDefaultRowHdrWidth" for ARM processors (or do a try
catch on v_cxDefaultRowHdrWidth and in the catch section retry with
m_kcxDefaultRowHdrWidth)

Bye

Thanks Zanna!!! I got everything figured it out!!

>-----Original Message-----
>Jasmine wrote:
>> Hi Zanna,
>>
>> Sorry It's me Jasmine again!
>> After testing out your code, there's an error that I
>> couldn't fix. My code always stopped at this line for
some
>> reason:
>> cf = DirectCast(objCRowColors.Item(i), CellFormat)
>>
>> The problem might be the CellFormat structure.
>
>Yes, this is a structure where I store fore/back colors:
>
>I changed its name to a more understandable
>
> Private Structure CellColorInfo
> Public Back As Color
> Public Fore As Color
> Public Sub New(ByVal backColor As Color,
ByVal foreColor As
>Color)
> Back = backColor
> Fore = foreColor
> End Sub
> End Structure
>
>Also, for the previous "m_kcxDefaultRowHdrWidth" tips, if
you use it be
>sure you use "v_cxDefaultRowHdrWidth" for ARM processors
(or do a try
>catch on v_cxDefaultRowHdrWidth and in the catch section
retry with
>m_kcxDefaultRowHdrWidth)
>
>Bye
>
>.
>