reload dll functions from anothe dll, C#

Question

Hi, I have 2 unmanaged dlls wich have exactly same set of function (but slighly different logic).

How can I switch between these 2 ddls during runtime?

now I have:

[DllImport("one.dll")]
public static extern string _test_mdl(string s);

Answer 1

Define them in different C# classes?

static class OneInterop
{
 [DllImport("one.dll")]
 public static extern string _test_mdl(string s);
}

static class TwoInterop
{
 [DllImport("two.dll")]
 public static extern string _test_mdl(string s);
}

Answer 2

I haven't ever had to use this, but I think the EntryPoint can be specified in the declaration. Try this:

    [DllImport("one.dll", EntryPoint = "_test_mdl")]
    public static extern string _test_mdl1(string s);

    [DllImport("two.dll", EntryPoint = "_test_mdl")]
    public static extern string _test_mdl2(string s);

DllImportAttribute.EntryPoint Field

Answer 3

Expanding on the existing answers here. You comment that you don't want to change existing code. You don't have to do that.

[DllImport("one.dll", EntryPoint = "_test_mdl")]
public static extern string _test_mdl1(string s);

[DllImport("two.dll", EntryPoint = "_test_mdl")]
public static extern string _test_mdl2(string s);

public static string _test_mdl(string s)
{
    if (condition)
        return _test_mdl1(s);
    else
        return _test_mdl2(s);
}

You keep using _test_mdl in your existing code, and just place the if-statement in a new version of that method, calling the correct underlying method.

Answer 4

You could still use dynamic loading and call LoadLibraryEx (P/Invoke), GetProcAddress (P/Invoke) and Marshal.GetDelegateForFunctionPointer (System.Runtime.InterOpServices).

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