Err.LastDllError - what's the .Net equivalnet?

[Merrion]

How can I get similar functionality to Err.LastDllError (from VB5/6) in VB.Net? I presume GetLastError api call is still suspect because of API functions that may trample on the error code being called internally by the programming language?

[Volte]

The Err object still exists in VB.NET, along with LastDllError, but I'm

not sure of the programming ethics that go along with it, since it's in the

Microsoft.VisualBasic namespace, which as I understand is the compatability

class. It should make a fine placeholder until you find a better way, however.

[Derek Stone]

System.Runtime.InteropServices.Marshal.GetLastWin32Error

[divil]

...it's in the

Microsoft.VisualBasic namespace, which as I understand is the compatability

class...

 

Only if you believe CL's lies!

[Derek Stone]

Microsoft can call it whatever they want. That's partly what it's there for (it obviously also serves as the runtime).

[Merrion]

*Resolved* Err.LastDllError

 

System.Runtime.InteropServices.Marshal.GetLastWin32Error

 

Just what i was looking for - thanks...

[Merrion]

It appears that you need to set the "SetLastError" attribute to make use of this e.g.:

 

<System.Runtime.InteropServices.DLLImport("winspool.drv",EntryPoint:="GetJob",SetLastError:=True, _ 
 CallingConvention:=CallingConvention.StdCall>_
Private Function GetJob(ByVal mhPrinter As Int32,  _ 
                                     ByVal dwJobId As Int32, _ 
                                     ByVal Level As Print_Job_Command_Levels, _ 
                                     ByVal lpJob As Int32, _ 
                                     ByVal cbBuf As Int32, _ 
                                     ByRef lpSizeNeeded As Int32) As Boolean

End Function

 

Incidentally - I'm not sure about "ByVal lpJob As Int32,". How should I pass a pointer to a byte buffer in?

 

Thanks in advance,

Duncan

[Derek Stone]

Make a call to Marshal.AllocHGlobal which will return an IntPtr to a memory location. Call Marshal.Copy to transfer the managed byte array to unmanaged memory. Then call .ToInt32 on the IntPtr to convert the pointer to an integer that GetJob will recognize. Finally unallocate the memory using Marshal.FreeHGlobal. Catch all that? ;)

[Merrion]

Excellent - muchos gracias..