System.Windows.Forms.TextBoxBase.GetLineFromCharIndex C# (CSharp) Метод

		public virtual int GetLineFromCharIndex (int index)
		{
			//TODO:
			return -1;
		}
	}

 public override int GetLineFromCharIndex(int charIndex)
 => _owningTextBoxBase.IsHandleCreated
         ? _owningTextBoxBase.GetLineFromCharIndex(charIndex)
         : -1;