A reference to the "....dll" could not be added.Please make sure that the file is accessible and that it is a valid assembly or

Question

When i add a .dll file as a reference in C# application it shows an error :

A reference to the "....dll" could not be added.Please make sure that the file is accessible and that it is a valid assembly or COM component.

 

Willfin David

Answer 1

I assume you are working with VS2005. So here is the work around for that

Execute "tlbimp <....>.dll"

<Drive>:\Program Files\Microsoft Visual Studio 8\SDK\v2.0\Bin>TlbImp.exe <....>.dll

This command  creates <...>CORELib.dll and add it as a reference to the project.

Hope this works, Let me know the result..

 

 

Answer 2

I have compiled as said but it shows the error,

TlbImp : error TI0000 : The input file 'E:\dotnet\Projects\ABClib128\ABClib.dll' is not a valid type library.

 

WIllfin

Answer 3

I think you need to build your own Interop dll

check this link

http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=272955&SiteID=1

 

Answer 4

I cannot build an other dll file because this .dll file is given by the client as a driver for communicating with the USB port. Any suggestions?

Willfin

Answer 5

Try this work around..

For the <..>.dll with a strong name:
First: sn -k mykey1.snk
Second: tlbimp <...>.dll /out: mydll1.dll /keyfile:mykey1.snk

Answer 6

It shows the same error:

TlbImp : error TI0000 : The input file 'E:\dotnet\DeviceDriverAPI\Devi
ceDriverAPI\ABClib.dll' is not a valid type library.

Willfin

Answer 7

It shows the same error:

TlbImp : error TI0000 : The input file 'E:\dotnet\DeviceDriverAPI\Devi
ceDriverAPI\ABClib.dll' is not a valid type library.

What does this represent "is not a valid type library.".Whether the dll contains code other than CSharp.?

Whether the dll have to be changed?

Willfin

Answer 8

hi,

to reference assembly in .net the assembly must have .net metadata format, not like the old assembly, i don't know how to reference the old dll files but once i heard  you can do that by p/invoke, as i said i didn't do that b4 so i can't provide more information but you might find this link usefull

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnnetcomp/html/PInvokeLib.asp

or you can search MSDN for that

http://lab.msdn.microsoft.com/search/Default.aspx?__VIEWSTATE=&query=p%2Finvoke&siteid=0&tab=0

hope this helps

Answer 9

Hi,

       When i add a .dll file(which has been developed in Visual Basic) as a reference  in c# application it shows an error:

A reference to the "....dll" could not be added.Please make sure that the file is accessible and that it is a valid assembly or COM component.

Could u give me a solution.

Answer 10

Have you tried to register the dll first using regsvr32 <dllName> ? I tried doing that and could use the dll in the .net project.

Answer 11

Tried the above solution..but no luck !!!

Answer 12

I have had VS2005, both standard and express edtiions, lock up and stop when I mix C# and VB.  By that I mean this.  I have a VB project, and want to use a .dl created with C#, and vice-versa.  Doesn't happen all the time, but only when I mix the languages through .dll files that contain forms.

 

Rudedog

Answer 13

Use P/Invoke instead. I assume you know the functions you need to call in the dll, so create a static nested called NativeMethods (for consistency) and add the external method signatures to it. Mark each extern method with the DllImport(string) attribute:

Code Snippet

private static class NativeMethods

{

   internal const string DllName = "ABClib.dll"; // handy const

    [DllImport(DllName)]

    internal static extern <returntype> MethodName(parameters...);

    //...

}

The dll must either be a registered server or in the same directory as the process image (exe). I suggest you add the dll-file to your project, and set its 'Copy to Output Directory' property to 'Copy always' or 'Copy if newer', that way it's easy to debug your program from VS.

Answer 14

I have the same problem.  Apparently this problem has been known for over a year and there's still no solution.  The DLL is fine -- the problem is with the Microsoft *** we're using for development!

 

This happens regularly.  Just this morning I tried to open an attached bitmap in Microsoft Outlook.  It refused, with a cryptic error message.  Imagine that: The Microsoft *** wouldn't even open a simple bitmap file!  I Googled the error message and found the fix, requiring a change to an obscure Registry entry.

 

I'm learning Linux.

Answer 15

Could you point us at the fix you found on Google, please ? I have just found the exact same problem.

 

Using this DLL is fundamental to the RSS Screensaver C# example on the website. Clearly nobody tested it on a machine with just the DLL. Beggars belief that after so many years of building development tools something as poor as this could stay out there for so long. And they wonder why we aren't rushing to adopt Vista ! How can we, when their own devt tools won't work with it. At least not outside Washington state !

Answer 16

It didn't seem to be asked in the original thread, but what kind of .dll is it?  Is it a regular Windows .dll?  Is is an ActiveX (COM) .dll, or is it a .Net Assembly?

 

If it is a standard Windows .dll, then you cannot reference it.  You must instead call the .dll using the platform invoke layer.  See pinvoke.net for examples of how calls are made.

 

If it is a COM dll, then it must be registered first and then you can reference it from the COM tab on the Add References Dialog.

 

If it is a .Net assembly, then you can find it by clicking Browse on the Add Reference dialog.

 

BTW:  This thread was almost 4 months old.

 

Chris

 

Answer 17

OK, After much searching, and finding no answer I have found a solution!!!!!

 

This is for C# in VS2005.

 

Step 1) Add the DLL as a resource.  To do this open the project, select the resources tab, select "add existing file" and add the DLL as a resource.

 

Step 2) Add the name of the DLL as a string resource.

 

Step 3) Add this code to your main form-load: (In this example my project is called "USBXpress_TestPanel", and the DLL file I'm using is "SiUSBXp.dll").

 

Code Snippet

if (System.IO.File.Exists(USBXpress_TestPanel.Properties.Resources.DLLName + ".DLL") == false)

{

System.IO.StreamWriter OutStream;

System.IO.BinaryWriter BinStream;

// Create the DLL file

OutStream = new System.IO.StreamWriter(USBXpress_TestPanel.Properties.Resources.DLLName + ".DLL", false);

BinStream = new System.IO.BinaryWriter(OutStream.BaseStream);

BinStream.Write(USBXpress_TestPanel.Properties.Resources.SiUSBXp);

BinStream.Close();

}

 

So the first time your code runs it will detect the missing DLL in it's default directory and create the file.  This way the DLL is actually embedded in your exe, so you don't have to mess with the deployment files or anything.

Answer 18

Whoat?

I dont think the problem is that the .DLL was not found.  The problem really seems to be that the DLL just is not written as a COM object, let alone written in a .Net language.

 

As stated by several users above  => you'll have to make your own calls in the DLL.  Do a google on this subject, add searches on : 'interop', 'p/invoke', 'platform invoke', 'marshal', 'DLLImport'.  I've been trought this dll-hell aswell...  You'll end up with a class looking like:

Code Snippet

[DllImport("SharedDLL", EntryPoint="PUBLICPROCEDURE")]

public static extern void PublicProcedure();

 

[DllImport("SharedDLL", EntryPoint="TAKESLONGRETURNSLONG")]

public static extern CWLong TakesLongReturnsLong(CWLong value);

 

[DllImport("SharedDLL", EntryPoint="TAKESSTRING")]

public static extern void TakesString([MarshalAs(UnmanagedType.BStr)] string value);

 

[DllImport("SharedDLL", EntryPoint="TAKESANDRETURNSSTRING")]

[return: MarshalAs(CWBString)]

public static extern string TakesAndReturnsString([MarshalAs(CWBString)] string value);

 

 

 

 

Then, you can use your local methods in your code...

For example... MyClass.TakesString("Hello World") sends the string "hello world" to the procedure takesstring(string value) in  shareddll.dll, wich is located right next to my .exe (or in the windows/system32 folder).

 

I'm pretty sure that when you got the DLL, there was some kind of documentation about the entry points...

 

 

Answer 19

OK, After much searching, and finding no answer I have found a solution!!!!!

 

This is for C# in VS2005.

 

Step 1) Add the DLL as a resource.  To do this open the project, select the resources tab, select "add existing file" and add the DLL as a resource.

 

Step 2) Add the name of the DLL as a string resource.

 

Step 3) Add this code to your main form-load: (In this example my project is called "USBXpress_TestPanel", and the DLL file I'm using is "SiUSBXp.dll").

 

Code Snippet

if (System.IO. File .Exists(USBXpress_TestPanel.Properties. Resources .DLLName + ".DLL" ) == false )

{

System.IO. StreamWriter OutStream;

System.IO. BinaryWriter BinStream;

// Create the DLL file

OutStream = new System.IO. StreamWriter (USBXpress_TestPanel.Properties. Resources .DLLName + ".DLL" , false );

BinStream = new System.IO. BinaryWriter (OutStream.BaseStream);

BinStream.Write(USBXpress_TestPanel.Properties. Resources .SiUSBXp);

BinStream.Close();

}

 

 

 

So the first time your code runs it will detect the missing DLL in it's default directory and create the file.  This way the DLL is actually embedded in your exe, so you don't have to mess with the deployment files or anything.

Thanks, this helped me!!! was searching for hours how to use this 3rd party API created in older version of VS. It was giving me the same error message... I am using Visual Studios 2008.

Answer 20

Encountering same problem

(((((A reference to the "vixDiskLib.dll" could not be added.Please make sure that the file is accessible and that it is a valid assembly or COM component. )))

...

...

...

I m unable to get success at the specifed solution written above. Plz help me out quickly. I've stuck at this problem since one year.Now itz very very urgent.Plz....................

Answer 21

This worked for me. Many thanks

Answer 22

so good 非常正确，Thank you very much

Answer 23

This solutions worked for me. It seems the dll I was using was built using Visual Basic. That's why registering it with regsvr32 was necessary.

 

Thanks EarthChild!

Answer 24

:) Thanks, this did the trick!

Answer 25

it must work, i tried it

you have to install the dll using the regsvr32

Answer 26

Dear Mattster --

Your answer is GREAT and it really worked for me.

I did change (hopefully improve) it a little bit by employing a "using" block, etc, as noted below...

string myDllFileName = MyProject.Properties.Resources.DLLName.Trim() + ".dll";
if (!System.IO.File.Exists(myDllFileName))
{
	using (System.IO.StreamWriter myOutStream = new System.IO.StreamWriter(myDllFileName, append: false))
	{
		System.IO.BinaryWriter myBinStream = new System.IO.BinaryWriter(myOutStream.BaseStream);
		myBinStream.Write(MyProject.Properties.Resources.p4bridge);
	}
}

Thanks.

-- Mark Kamoski

Answer 27

I assume you are working with VS2005. So here is the work around for that

Execute "tlbimp <....>.dll"

<Drive>:\Program Files\Microsoft Visual Studio 8\SDK\v2.0\Bin>TlbImp.exe <....>.dll

This command  creates <...>CORELib.dll and add it as a reference to the project.

Hope this works, Let me know the result..

This worked for me. Thank you very much!

Answer 28

Dear mkamoski2:

I can't seem to get this to work for VS2010. It seems like the file exists but then in a following step, the program can't find the dll. I'm also using the dll from SiLabs. I have added the dll and SLUSBXpressDLL.cs as resources. Here's my code snippet:

                string myDllFileName = HIPPY.Properties.Resources.SiUSBXp + ".dll";
                MessageBox.Show("starting System.IO.File.Exists"); 
                if (System.IO.File.Exists(myDllFileName) == false)
                {
                    using (System.IO.StreamWriter myOutStream = new System.IO.StreamWriter(myDllFileName, append: false))
                    {
                        System.IO.BinaryWriter myBinStream = new System.IO.BinaryWriter(myOutStream.BaseStream);
                        myBinStream.Write(HIPPY.Properties.Resources.SiUSBXp);
                    }
                }
                else
                    MessageBox.Show("System.IO.File.Exists(myDllFileName)");
                MessageBox.Show("starting SLUSBXpressDLL.SI_GetNumDevices");
                SLUSBXpressDLL.Status = SLUSBXpressDLL.SI_GetNumDevices(ref DevNum);
                MessageBox.Show("DevNum = " , DevNum.ToString());

Any ideas?

Thanks,

John