[RichTextBoxEntension] – Anexar texto multilinha / multicolor

public static class RichTextBoxExtensions
{
public static void AppendText(this RichTextBox oBox, string sText, Color oColor)
{
oBox
.SelectionStart = oBox.TextLength;
oBox
.SelectionLength = 0;
oBox
.SelectionColor = oColor;
oBox
.AppendText(sText + "rn");
oBox
.SelectionColor = oBox.ForeColor;
oBox
.ScrollToCaret();
}
}