/// <summary>Конструктор</summary>
/// <param name="layer">Слой</param>
/// <param name="fieldName">Имя поля</param>
/// <param name="fieldType">Тип поля</param>
/// <param name="width">Ширина</param>
/// <param name="precision">Точность</param>
/// <param name="indexed"></param>
/// <param name="unique"></param>
protected internal Field(MiLayer layer, string fieldName, FieldType fieldType, int width, int precision,
int indexed, int unique)
{
IntPtr fieldId = MiApi.mitab_c_add_field(layer.Handle,
fieldName, (int)fieldType, width, precision, indexed, unique);;
this.Layer = layer;
this.Index = fieldId.ToInt32();
this.Name = fieldName;
this.Type = fieldType;
this.Precision = (short)precision;
this.Width = width;
}