Gets or sets an identifier for the Web Part.
[BrowsableAttribute(false)] [WebPartStorageAttribute(Storage = Storage.Shared)] public override string ID { get; set; }
The ID property will be written out by ASP.NET as the __WebPartId attribute on the tag for the Web Part.
Do not set this property when a Web Part is contained in a WebPartZone control; the Web Part infrastructure automatically sets this value.