Find Whether Specific Row Contains a Selected (Highlighted) Cell - vb.net

Question

At the moment, I've created a loop which runs through every cells in my datagridview to find if any cells are selected (highlighted), and if so that cell's row/ column header backcolor changes. The problem I have with this is that once the row and column count start to become a large amount, I start experiencing lag. So I wondering does anybody know a way of instantly being able to find whether a row or column contains a selected or highlighted cell without using a loop.
I was hoping that something like me.datagridview1.rows(1).selectedcells.count would exist, but haven't been able to find something like that, that works.
The other option (which I'd prefer not to do), is color the headercells as the selection is made.
Here is what I am using to find the selections. I have it looping through only the displayed cells to reduce the lag (which works), but I need the headercells colored, even when the selected cells are out of view (which then doesn't work).
a = .FirstDisplayedCell.RowIndex
Do While a < .FirstDisplayedCell.RowIndex + .DisplayedRowCount(True)
b = .FirstDisplayedCell.ColumnIndex
Do While b < .FirstDisplayedCell.ColumnIndex + .DisplayedColumnCount(True)
If .Rows(a).Cells(b).Selected = False Then
.Rows(a).HeaderCell.Style.BackColor = colorfieldheader
.Columns(b).HeaderCell.Style.BackColor = colorfieldheader
End If
b += 1
Loop
a += 1
Loop
a = .FirstDisplayedCell.RowIndex
Do While a < .FirstDisplayedCell.RowIndex + .DisplayedRowCount(True)
b = .FirstDisplayedCell.ColumnIndex
Do While b < .FirstDisplayedCell.ColumnIndex + .DisplayedColumnCount(True)
If .Rows(a).Cells(b).Selected = True Then
.Rows(a).HeaderCell.Style.BackColor = colorfieldheaderhighlight
.Columns(b).HeaderCell.Style.BackColor = colorfieldheaderhighlight
End If
b += 1
Loop
a += 1
Loop

Answer 1

You can do something like this C# code:
private void dataGridView1_SelectionChanged(object sender, EventArgs e)
{
foreach (DataGridViewCell cell in dataGridView1.SelectedCells)
{
dataGridView1.Rows[cell.RowIndex].DefaultCellStyle.BackColor = Color.Red;
}
}
Ensure that the event handler is attached after data binding.
If you are highlighting the row same a selected cell (blue), you might want to set SelectionMode as FullRowSelect for the DataGridView. Like this:
dataGridView1.SelectionMode = DataGridViewSelectionMode.FullRowSelect;

Answer 2

place this code in your data grid view MouseDown event ...
private void dataGridView1_CellMouseDown(object sender, DataGridViewCellMouseEventArgs e)
{
if (e.Button == MouseButtons.Left )
{
this.dataGridView1.Rows[e.RowIndex].DefaultCellStyle.BackColor = Color.Red;
}
}
and for more info use how to highlight specific row in datagridview in c#