Does anyone know what is wrong with these imports from User32.dll?

[Will Pittenger]

The constants.windowLongIndices type is an enum. That is there so I can
ensure the appropriate values are always used. Since I had to replace the
GWL macros with new values, I decided to prevent passing 7 -- or whatever
the author of the caller felt like. I tried both ExactSpelling=true and
setting the entry point manually. I also tried forcing the Unicode and
ASCII versions. (According to the Win32 documentation, both functions have
UNICODE versions in NT/2000/XP. My tests are on a XP Pro SP1 system.


[System.Runtime.InteropServices.DllImport("user32", SetLastError=true)]
public static extern IntPtr SetWindowLongPtr(IntPtr hWnd,
constants.windowLongIndices index, IntPtr iNewValue);

[System.Runtime.InteropServices.DllImport("user32", SetLastError=true)]
public static extern IntPtr GetWindowLongPtr(IntPtr hWnd,
constants.windowLongIndices index);

 

[Dmitriy Lapshin [C# / .NET MVP]]

Hello Will,

Try

public static extern IntPtr SetWindowLongPtrW(IntPtr hWnd,
constants.windowLongIndices index, IntPtr iNewValue);

and specify the ExactSpelling option. You can also apply
the MarshalAs attribute to the "index" argument to ensure
it is indeed treated as an int32 type parameter.

 

[Mattias Sjögren]

Will,

On Win32, SetWindowLongPtr is implemented as a macro that just calls
the old SetWindowLong function (and the same is true for
GetWindowLong/Ptr). So you have to specify that as your entry point

[DllImport("user32", SetLastError=true, EntryPoint="SetWindowLong",
CharSet=CharSet.Auto)]
public static extern IntPtr SetWindowLongPtr(IntPtr hWnd,
constants.windowLongIndices index, IntPtr iNewValue);



Mattias

 

[Dmitriy Lapshin [C# / .NET MVP]]

Gosh, how could I forget this old trick! So, as an additional advice to the
original poster: if you have Platform SDK installed, you can investigate the
corresponding API declaration in the Windows header files to ensure given
API function is not actually a macro or something.

 

[Will Pittenger]

That turns out to be correct. Given that we are supposed to take
precautions to ensure portablity to 64-bit code, how should this be
imported?

 

[Will Pittenger]

I think that Mattias had the better answer.

----------
Will Pittenger
E-Mail: mailto:[email protected]
All mail filtered by Qurb (www.qurb.com)

Hello Will,

Try

public static extern IntPtr SetWindowLongPtrW(IntPtr hWnd,
constants.windowLongIndices index, IntPtr iNewValue);

and specify the ExactSpelling option. You can also apply
the MarshalAs attribute to the "index" argument to ensure
it is indeed treated as an int32 type parameter.

--
Dmitriy Lapshin [C# / .NET MVP]
X-Unity Test Studio
http://www.x-unity.net/teststudio.aspx
Bring the power of unit testing to VS .NET IDE

The constants.windowLongIndices type is an enum. That is there so I can
ensure the appropriate values are always used. Since I had to replace the
GWL macros with new values, I decided to prevent passing 7 -- or whatever
the author of the caller felt like. I tried both ExactSpelling=true and
setting the entry point manually. I also tried forcing the Unicode and
ASCII versions. (According to the Win32 documentation, both functions have
UNICODE versions in NT/2000/XP. My tests are on a XP Pro SP1 system.


[System.Runtime.InteropServices.DllImport("user32", SetLastError=true)]
public static extern IntPtr SetWindowLongPtr(IntPtr hWnd,
constants.windowLongIndices index, IntPtr iNewValue);

[System.Runtime.InteropServices.DllImport("user32", SetLastError=true)]
public static extern IntPtr GetWindowLongPtr(IntPtr hWnd,
constants.windowLongIndices index);