protected override bool OkToChange(int hvo)
{
if (!base.OkToChange(hvo))
return false;
ITsString tss = OldValue(hvo);
if (tss == null)
{
ITsStrFactory tsf = TsStrFactoryClass.Create();
tss = tsf.MakeString("", m_accessor.WritingSystem);
}
m_textSourceInit.SetString(tss);
int ichMin, ichLim;
m_pattern.FindIn(m_ts, 0, tss.Length, true, out ichMin, out ichLim, null);
return ichMin >= 0;
}
