how to provide a dll file path to DllImport[""]

Question

0.00/5 (No votes)

See more:

Hi all,

I want to set the .dll file path to the function DllImport[(filepath)] from app.config file instead of Dllimport[("C://dll.dll")]

Please help me in this regard.

Thanks in Advance.

Posted 12-Jun-11 22:51pm

baskaran789

Updated 12-Jun-11 23:07pm

Ramalinga Koushik

v2

Add a Solution

2 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

parmar_punit · Answer 1 · 2011-06-12T23:08:00

C#

using System;
using System.Runtime.InteropServices;

class Example
{
    // Use DllImport to import the Win32 MessageBox function.
    [DllImport("user32.dll", CharSet = CharSet.Unicode)]
    public static extern int MessageBox(IntPtr hWnd, String text, String caption, uint type);

    static void Main()
    {
        // Call the MessageBox function using platform invoke.
        MessageBox(new IntPtr(0), "Hello World!", "Hello Dialog", 0);
    }
}

For more details...
See this link
and also see this link

Sergey Alexandrovich Kryukov · Answer 2 · 2011-06-12T23:09:00

You cannot to it. Here is why: let's look at the System.Runtime.InteropServices.DllImportAttribute MSDN help page http://msdn.microsoft.com/en-us/library/system.runtime.interopservices.dllimportattribute.dllimportattribute.aspx[^]: there is only one constructor with only one parameter: a DLL name. This can be not just the file name, but also a full assembly name in case if an unmanaged DLL file is included in an assembly — please look at the code sample.

That's it. I cannot be anything else. (I did not discuss positional parameters used in attribute application, they are actually properties, not call parameters.)

Now, the statement for the application of attribute (in this case, the the extern method declaration) is not a "real" method call. In particular, parameters can be only the constants (or types via typeof). It can be an immediate constant or a explicitly declared constant (much better), but a real constant, not a read-only variable.

For that reason, it cannot be anything read from the file, a configuration file or any other file, as data read from file cannot be constant.

Conclusion: not only it is impossible, but I've proved that.

Now, I'm curious: why doing that?

Perhaps you need different DLLs to be pluggable. No, this is not how it works. A linked DLL name is compiled into assembly executable module, that's it. If you need to have a pluggable unmanaged DLLs (depending on configuration or other factor) you need completely different approach: P/Invoke Windows APIs LoadLibrary and GetProcAddress and load DLLs during run time.

—SA

how to provide a dll file path to DllImport[""]

2 solutions

Solution 1

Solution 2

Add your solution here

Preview 0