Want several font colors in my cell - richtextbox

Question

Im creating a new cell = new XRTableCell();
I'll show a sample of my code.
I always ending up with the same color in my cell, even if I change it in my "If".
foreach (TaskTime tt in di.TaskTimes[i])
{
.....
TimeToAdd = ClassLibrary.Utils.GetTimeStringFromSec(tt.FromSec % 86400) + " - " + ClassLibrary.Utils.GetTimeStringFromSec(tt.UntilSec % 86400) + " (" + tt.Abbreviation+ ")";
if (taskTimeTextBox.Text.Length > 0)
taskTimeTextBox.Text += "\n";
taskTimeTextBox.Text += TimeToAdd;
if (tt.OnOtherCostDivision)
{
taskTimeTextBox.SelectionStart = taskTimeTextBox.Find(TimeToAdd);
taskTimeTextBox.SelectionFont = new Font("Calibri", 9, FontStyle.Italic);
taskTimeTextBox.SelectionColor = Color.Gray;
}
else
{
taskTimeTextBox.SelectionStart = taskTimeTextBox.Find(TimeToAdd);
taskTimeTextBox.SelectionFont = new Font("Calibri", 9, FontStyle.Italic);
taskTimeTextBox.SelectionColor = Color.Blue;
}
richTxtObject.Rtf = taskTimeTextBox.Rtf;
cell.Controls.Add(richTxtObject);
}
row.Cells.Add(cell);

Answer 1

Soulved it! Didn't worked when I had it this way "taskTimeTextBox.Text += xxxxxxxx ". So I made a list of string, saved my text in if it were "onOtherCostDivision". Later on I hade to loop true my list and see if the final taskTimeTextBox.Text had the text in it and in that cause I added the color.
foreach (var task in taskCostDivList)
{
if (taskTimeTextBox.Text.Contains(task))
{
taskTimeTextBox.SelectionStart = taskTimeTextBox.Find(task);
taskTimeTextBox.Font = new Font("Calibri", 9, FontStyle.Italic);
taskTimeTextBox.SelectionColor = Color.Gray;
}
else
{
taskTimeTextBox.Font = new Font("Calibri", 9, FontStyle.Regular);
taskTimeTextBox.SelectionColor = Color.Black;
}
}