/**
* Set cell color. This sets some associated values; for finer control
* you may want to access these elements individually.
* @param rgbStr - the desired cell color, in the hex form "RRGGBB".
*/
public void SetColor(string rgbStr)
{
CT_TcPr tcpr = ctTc.IsSetTcPr() ? ctTc.tcPr : ctTc.AddNewTcPr();
CT_Shd ctshd = tcpr.IsSetShd() ? tcpr.shd : tcpr.AddNewShd();
ctshd.color = ("auto");
ctshd.val = (ST_Shd.clear);
ctshd.fill = (rgbStr);
}