C#

private void zemin_MouseMove(object sender, MouseEventArgs e)
{
      if (!this.ClientRectangle.Contains(e.X, e.Y)) return;
      AtkiCozguNo(e.X, e.Y);//find row and column numbers of grid.
      if (!tusaBasildi) return;//ensure left-mousebutton pressed.

      if (atki == sonAtki & cozgu == sonCozgu) return;//if it's not new cell return.
      sonAtki = atki;
      sonCozgu = cozgu;
      renkKontrol(e.X, e.Y);//check color

}

private void renkKontrol(int x, int y)//find color x and y coordinate
{
             if(bitmapPixel.GetPixel(this, x, y).ToArgb()==this.BackColor.ToArgb())
                   {
                    kutuDoldur(Color.Red);//fill cell with color red
                   }
             if(bitmapPixel.GetPixel(this, x, y).ToArgb()==Color.Red.ToArgb())
                   {
                    kutuDoldur(this.BackColor);//fill cell with color of Control Backcolor
                   }

}

private void kutuDoldur(Color renk)//fill rectangle with desired color onto bitmap kutuResmi
           {
                   using (Graphics myKutu = Graphics.FromImage(kutuResmi))
                  {
                     myKutu.FillRectangle(new SolidBrush(renk),new                    Rectangle(xKoordinat,yKoordinat,kutuEbadı,kutuEbadı));
                  }

                Invalidate();
          }

private void zemin_Paint(object sender, PaintEventArgs e)
       {
          e.Graphics.DrawImage(kutuResmi, 0, 0);//place bitmap kutuResmi on Control
       }

if (atki == sonAtki && cozgu == sonCozgu) return; // Double &&?

Som Shekhar wrote:

assigning it to a view and change row filter?

DataView view = table.DefaultView;
view.RowFilter = "Value>2";

DataTable table = new DataTable();
table.Columns.Add(columnName);

for (int i = 0; i < 1000000; i++)
{
    table.Rows.Add(i);
}
MessageBox.Show("Loaded", "");


//---------------------------------------------------
string condition = columnName + ">500 AND " + columnName + "<10000";
DateTime timeStart = DateTime.Now;
DataView view = table.DefaultView;
view.RowFilter = condition;
DataTable newTable = view.ToTable();
DateTime timeStop = DateTime.Now;

TimeSpan span = timeStop - timeStart;
MessageBox.Show(span.TotalMilliseconds.ToString(), "");
//---------------------------------------------------
timeStart = DateTime.Now;
DataRow[] rows = table.Select(condition);
timeStop = DateTime.Now;
span = timeStop - timeStart;
MessageBox.Show(span.TotalMilliseconds.ToString(), "");