Generic Interface Implementation in C# Orcas Beta 1

[=?Utf-8?B?RG9uYWxkIFhpZQ==?=]

In C# 2, this works just fine:

public class foo : IEnumerable<string>
{
private string[] _list;
public IEnumerator<stringGetEnumerator()
{
foreach (string s in _list)
yield return s;
}
}

However Orcas complains that:

'myNS.foo' does not implement interface member
'System.Collections.IEnumerable.GetEnumerator()'. 'myNS.foo.GetEnumerator()'
cannot implement 'System.Collections.IEnumerable.GetEnumerator()' because it
does not have the matching return type of 'System.Collections.IEnumerator'.

It appears that I'll have to add an explicit non-generic interface
implementation to appease the compiler:

IEnumerator IEnumerable.GetEnumerator()
{
return GetEnumerator();
}

Just wondering whether this is a change in generics implementation or just a
bug in beta 1.

Cheers,
Don

[colin]

"Donald Xie" <do********@msdn.nospamwrote in message
news:FA**********************************@microsof t.com...

In C# 2, this works just fine:

public class foo : IEnumerable<string>
{
private string[] _list;
public IEnumerator<stringGetEnumerator()
{
foreach (string s in _list)
yield return s;
}
}

However Orcas complains that:

'myNS.foo' does not implement interface member
'System.Collections.IEnumerable.GetEnumerator()'.
'myNS.foo.GetEnumerator()'
cannot implement 'System.Collections.IEnumerable.GetEnumerator()' because
it
does not have the matching return type of
'System.Collections.IEnumerator'.

It appears that I'll have to add an explicit non-generic interface
implementation to appease the compiler:

IEnumerator IEnumerable.GetEnumerator()
{
return GetEnumerator();
}

Just wondering whether this is a change in generics implementation or just
a
bug in beta 1.

Cheers,
Don

ive just done a simple binary sorted tree class,
and was confused by this error too,
I ended up inheriting only the non generic collection class stuff
System.Collections.CollectionBase

not sure what the pros and cons are ...

Colin =^.^=

[Nicholas Paldino [.NET/C# MVP]]

Donald,

Nothing has changed, the same error comes up in C# 2.0, so it's not an
error in Orcas. This is what I get in C# 2.0:

Error 1 'foo' does not implement interface member
'System.Collections.IEnumerable.GetEnumerator()'. 'foo.GetEnumerator()' is
either static, not public, or has the wrong return type.
c:\temp\ConsoleApplication1\ConsoleApplication1\Pr ogram.cs 86 14
ConsoleApplication1

--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard.caspershouse.com

"Donald Xie" <do********@msdn.nospamwrote in message
news:FA**********************************@microsof t.com...

In C# 2, this works just fine:

public class foo : IEnumerable<string>
{
private string[] _list;
public IEnumerator<stringGetEnumerator()
{
foreach (string s in _list)
yield return s;
}
}

However Orcas complains that:

'myNS.foo' does not implement interface member
'System.Collections.IEnumerable.GetEnumerator()'.
'myNS.foo.GetEnumerator()'
cannot implement 'System.Collections.IEnumerable.GetEnumerator()' because
it
does not have the matching return type of
'System.Collections.IEnumerator'.

It appears that I'll have to add an explicit non-generic interface
implementation to appease the compiler:

IEnumerator IEnumerable.GetEnumerator()
{
return GetEnumerator();
}

Just wondering whether this is a change in generics implementation or just
a
bug in beta 1.

Cheers,
Don

[=?Utf-8?B?RG9uYWxkIFhpZQ==?=]

Hmm, I was using VS2005 SP1, which seems to be happy with this. What version
are you using?

Thanks,
Don

"Nicholas Paldino [.NET/C# MVP]" wrote:

Donald,

Nothing has changed, the same error comes up in C# 2.0, so it's not an
error in Orcas. This is what I get in C# 2.0:

Error 1 'foo' does not implement interface member
'System.Collections.IEnumerable.GetEnumerator()'. 'foo.GetEnumerator()' is
either static, not public, or has the wrong return type.
c:\temp\ConsoleApplication1\ConsoleApplication1\Pr ogram.cs 86 14
ConsoleApplication1

--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard.caspershouse.com

"Donald Xie" <do********@msdn.nospamwrote in message
news:FA**********************************@microsof t.com...

In C# 2, this works just fine:

public class foo : IEnumerable<string>
{
private string[] _list;
public IEnumerator<stringGetEnumerator()
{
foreach (string s in _list)
yield return s;
}
}

However Orcas complains that:

'myNS.foo' does not implement interface member
'System.Collections.IEnumerable.GetEnumerator()'.
'myNS.foo.GetEnumerator()'
cannot implement 'System.Collections.IEnumerable.GetEnumerator()' because
it
does not have the matching return type of
'System.Collections.IEnumerator'.

It appears that I'll have to add an explicit non-generic interface
implementation to appease the compiler:

IEnumerator IEnumerable.GetEnumerator()
{
return GetEnumerator();
}

Just wondering whether this is a change in generics implementation or just
a
bug in beta 1.

Cheers,
Don

[Jon Skeet [C# MVP]]

Donald Xie <do********@msdn.nospamwrote:

Hmm, I was using VS2005 SP1, which seems to be happy with this. What version
are you using?

I'm using VS2005 SP1 and get the same failure.

Complete code:

using System;
using System.Collections.Generic;

public class Test : IEnumerable<string>
{
private string[] _list;
public IEnumerator<stringGetEnumerator()
{
foreach (string s in _list)
yield return s;
}

static void Main()
{
}
}
Compilation (including compiler version number):

C:\Users\Jon\Test>csc Test.cs
Microsoft (R) Visual C# 2005 Compiler version 8.00.50727.312
for Microsoft (R) Windows (R) 2005 Framework version 2.0.50727
Copyright (C) Microsoft Corporation 2001-2005. All rights reserved.

Test.cs(4,14): error CS0536: 'Test' does not implement interface member
'System.Collections.IEnumerable.GetEnumerator()'.
'Test.GetEnumerator()'
is either static, not public, or has the wrong return type.
c:\Windows\Microsoft.NET\Framework\v2.0.50727\msco rlib.dll: (Location
of symbol
related to previous error)
Test.cs(7,32): (Location of symbol related to previous error)

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too

[=?Utf-8?B?RG9uYWxkIFhpZQ==?=]

Thanks again Jon. Well I've just tried on my office PC with VS2..5 SP1, and I
get this error too!

I'll double check on my home PC when I get back tonight...

Cheers,
Don

"Jon Skeet [C# MVP]" wrote:

Donald Xie <do********@msdn.nospamwrote:

Hmm, I was using VS2005 SP1, which seems to be happy with this. What version
are you using?

I'm using VS2005 SP1 and get the same failure.

Complete code:

using System;
using System.Collections.Generic;

public class Test : IEnumerable<string>
{
private string[] _list;
public IEnumerator<stringGetEnumerator()
{
foreach (string s in _list)
yield return s;
}

static void Main()
{
}
}
Compilation (including compiler version number):

C:\Users\Jon\Test>csc Test.cs
Microsoft (R) Visual C# 2005 Compiler version 8.00.50727.312
for Microsoft (R) Windows (R) 2005 Framework version 2.0.50727
Copyright (C) Microsoft Corporation 2001-2005. All rights reserved.

Test.cs(4,14): error CS0536: 'Test' does not implement interface member
'System.Collections.IEnumerable.GetEnumerator()'.
'Test.GetEnumerator()'
is either static, not public, or has the wrong return type.
c:\Windows\Microsoft.NET\Framework\v2.0.50727\msco rlib.dll: (Location
of symbol
related to previous error)
Test.cs(7,32): (Location of symbol related to previous error)

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too

[=?Utf-8?B?RG9uYWxkIFhpZQ==?=]

Excuse me when I'm pulling my foot from my mouth - the error is on my home PC
as well. Now I'm wondering what I was doing yesterday...

At least this is consistent so I just have to use the workaround.

Thanks for setting me straight Jon ;-)

Cheers,
Don

"Donald Xie" wrote:

Thanks again Jon. Well I've just tried on my office PC with VS2..5 SP1, and I
get this error too!

I'll double check on my home PC when I get back tonight...

Cheers,
Don

"Jon Skeet [C# MVP]" wrote:

Donald Xie <do********@msdn.nospamwrote:

Hmm, I was using VS2005 SP1, which seems to be happy with this. What version
are you using?

I'm using VS2005 SP1 and get the same failure.

Complete code:

using System;
using System.Collections.Generic;

public class Test : IEnumerable<string>
{
private string[] _list;
public IEnumerator<stringGetEnumerator()
{
foreach (string s in _list)
yield return s;
}

static void Main()
{
}
}
Compilation (including compiler version number):

C:\Users\Jon\Test>csc Test.cs
Microsoft (R) Visual C# 2005 Compiler version 8.00.50727.312
for Microsoft (R) Windows (R) 2005 Framework version 2.0.50727
Copyright (C) Microsoft Corporation 2001-2005. All rights reserved.

Test.cs(4,14): error CS0536: 'Test' does not implement interface member
'System.Collections.IEnumerable.GetEnumerator()'.
'Test.GetEnumerator()'
is either static, not public, or has the wrong return type.
c:\Windows\Microsoft.NET\Framework\v2.0.50727\msco rlib.dll: (Location
of symbol
related to previous error)
Test.cs(7,32): (Location of symbol related to previous error)

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too