First 30 % displayed columns in DataGridView - vb.net

Question

First of all: 30% doesn't matter. That's a question of design. We can also say the first 3 Displayed Columns.
In my DataGridView I am using BackgroundColors for Rows to pass the User some information.
To keep this information visible to the user while Rows are being selected the first 30% of the columns should get the same SelectionBack/ForeColor as the Back/ForeColor.
So far that has never been a problem using
.cells(0).Style.SelectionBackColor = .cells(0).Style.Backcolor
(and so on).
Now I added the function that allows the user to reorder the Columns which makes the following Statement become true:
ColumnIndex != DisplayedIndex.
That statement beeing true makes the SelectionBackColor-Changed cells be somewhere mixed in the row and not in the first columns anymore. It still does the job, but looks terrible.
Is there something like a "DisplayedColumns" collection in order of the .DisplayedIndex Value that i could use to call the first few DisplayedColumns? If not, how could I effectivly create one my own?
Edit:
The user can also hide specific columns, that do not matter for him. So we have to be aware of Column.DisplayedIndex and Column.Visble
Got it working with the following code:
Try
' calculate what is thirty percent
Dim colcount As Integer = oDic_TabToGridview(TabPage).DisplayedColumnCount(False)
Dim thirtyPercent As Integer = ((colcount / 100) * 30)
' Recolor the first 30 % of the Columns
Dim i As Integer = 0
Dim lastCol As DataGridViewColumn = oDic_TabToGridview(TabPage).Columns.GetFirstColumn(DataGridViewElementStates.Visible)
While i < thirtyPercent
.Cells(lastCol.Index).Style.SelectionBackColor = oCol(row.Item("Color_ID") - 1)
.Cells(lastCol.Index).Style.SelectionForeColor = Color.Black
lastCol = oDic_TabToGridview(TabPage).Columns.GetNextColumn(lastCol, DataGridViewElementStates.Visible, DataGridViewElementStates.None)
i += 1
End While
Catch ex As Exception
MsgBox(ex.Message & vbNewLine & ex.StackTrace)
End Try

Answer 1

Let us first assume you are coloring your rows somehow resembling the following manner:
Me.dataGridView1.Rows(0).DefaultCellStyle.BackColor = Color.PowderBlue
Me.dataGridView1.Rows(1).DefaultCellStyle.BackColor = Color.Pink
' ...etc.
In the DataGridView.CellPainting event handler, you can determine if the painting cell falls within the first N columns by utilizing the DataGridViewColumnCollection.GetFirstColumn and DataGridViewColumnCollection.GetNextColumn methods.
If the cell belongs to one these columns, set the cell's SelectionBackColor to the cell's BackColor. Otherwise set it to the default highlighting color.
Dim column As DataGridViewColumn = Me.dataGridView1.Columns.GetFirstColumn(DataGridViewElementStates.Visible)
e.CellStyle.SelectionBackColor = Color.FromName("Highlight")
' Example: Loop for the first N displayed columns, where here N = 2.
While column.DisplayIndex < 2
If column.Index = e.ColumnIndex Then
e.CellStyle.SelectionBackColor = e.CellStyle.BackColor
Exit While
End If
column = Me.dataGridView1.Columns.GetNextColumn(column, DataGridViewElementStates.Visible, DataGridViewElementStates.None)
End While
As a side note: You may want to consider changing the ForeColor on these cells for readability - depending on your row's BackColor choices. Likewise, if only a single cell is selected from one these first N columns, it can be difficult to notice.