> Thread-Topic: Bug in System.ComponentModel.PropertyDescriptorCollection.RemoveAt
> thread-index: AcSKrVvnvXkJMf1oQieBNKbzygCaIw==
> X-WBNR-Posting-Host: 195.97.95.38
> From: =?Utf-8?B?bW5z?= <mns@discussions.microsoft.com>
> Subject: Bug in System.ComponentModel.PropertyDescriptorCollection.RemoveAt
> Date: Wed, 25 Aug 2004 07:11:04 -0700
> Lines: 54
> Message-ID: <4E90DAAD-288B-4EC7-89E7-605B1FF0DF51@microsoft.com>
> MIME-Version: 1.0
> Content-Type: text/plain;
> charset="Utf-8"
> Content-Transfer-Encoding: 7bit
> X-Newsreader: Microsoft CDO for Windows 2000
> Content-Class: urn:content-classes:message
> Importance: normal
> Priority: normal
> X-MimeOLE: Produced By Microsoft MimeOLE V6.00.3790.0
> Newsgroups: microsoft.public.dotnet.framework.clr
> NNTP-Posting-Host: TK2MSFTNGXA03.phx.gbl 10.40.1.29
> Path: cpmsftngxa10.phx.gbl!TK2MSFTNGXA03.phx.gbl
> Xref: cpmsftngxa10.phx.gbl microsoft.public.dotnet.framework.clr:11703
> X-Tomcat-NG: microsoft.public.dotnet.framework.clr
>
> The following program reproduces a bug in
> System.ComponentModel.PropertyDescriptorCollection.RemoveAt: Removing any but
> the last item of the collection generates a System.ArgumentException.
>
> --- Start code to reproduce bug ---
> <pre>
> namespace PropertyDescriptorCollectionBug
> {
> class HasAProperty
> {
> public int Test1 { get { return 1; } }
> public int Test2 { get { return 2; } }
>
> static void Main(string[] args)
> {
> System.ComponentModel.PropertyDescriptorCollection collection =
> System.ComponentModel.TypeDescriptor.GetProperties(typeof(HasAProperty));
> System.Diagnostics.Debug.Assert(collection.Count == 2);
>
> System.ComponentModel.PropertyDescriptor[] array = new
> System.ComponentModel.PropertyDescriptor[collection.Count];
> collection.CopyTo(array, 0);
> collection = new System.ComponentModel.PropertyDescriptorCollection(array);
>
> collection.RemoveAt(0); <b>// Throws System.ArgumentException</b>
> }
> }
> }
> </pre>
> --- End code to reproduce bug ---
>
> Examining the implementation of this function with Reflector, I come up to
> this obviously untested implementation:
>
> <pre>
> public void RemoveAt(int index)
> {
> if (this.readOnly)
> {
> throw new NotSupportedException();
> }
> if (index < (this.propCount - 1))
> {
> Array.Copy(this.properties, ((int) (index + 1)),
> this.properties, index, ((int) (this.propCount - index))); <b>// Should be
> this.propCount - index - 1</b>
> }
> --this.propCount;
> }
> </pre>
>
> Off by one errors... Ahhhh...
>
> mns
>