blocks|key|1725691|text|我发现最简单的方法是导入两个具有不同名称的方法，并调用正确的方法。DLL只有在调用完成后才会被加载，所以这样做没问题：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1725692|[DllImport("MyDll32.dll",+EntryPoint+=+"Func1",+CallingConvention+=+CallingConvention.Cdecl)]
private+static+extern+int+Func1_32(int+var1,+int+var2);

[DllImport("MyDll64.dll",+EntryPoint+=+"Func1",+CallingConvention+=+CallingConvention.Cdecl)]
private+static+extern+int+Func1_64(int+var1,+int+var2);

public+static+int+Func1(int+var1,+int+var2)+{
++++return+IntPtr.Size+==+8+/*+64bit+*/+?+Func1_64(var1,+var2)+:+Func1_32(var1,+var2);
}|code-block|syntax|javascript|1725693|当然，如果您有许多导入，手动维护可能会变得相当麻烦。|1725694|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

I've found the simplest way to do this is to import the two methods with different names, and calling the right one. The DLL won't be loaded until the call is made so it's fine:

<pre><code>[DllImport("MyDll32.dll", EntryPoint = "Func1", CallingConvention = CallingConvention.Cdecl)]
private static extern int Func1_32(int var1, int var2);

[DllImport("MyDll64.dll", EntryPoint = "Func1", CallingConvention = CallingConvention.Cdecl)]
private static extern int Func1_64(int var1, int var2);

public static int Func1(int var1, int var2) {
 return IntPtr.Size == 8 /* 64bit */ ? Func1_64(var1, var2) : Func1_32(var1, var2);
}
</code></pre>

Of course, if you have many imports, this can be become quite cumbersome to maintain manually.

blocks|key|1939335|text|在本例中，我应该这样做(创建两个文件夹，x64和x86+%2B将具有相同名称的相应dll放入这两个文件夹中)：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1939336|using+System;
using+System.Runtime.InteropServices;
using+System.Reflection;
using+System.IO;

class+Program+{
++++static+void+Main(string[]+args)+{
++++++++var+path+=+Path.GetDirectoryName(Assembly.GetEntryAssembly().Location);
++++++++path+=+Path.Combine(path,+IntPtr.Size+==+8+?+"x64"+:+"x86");
++++++++bool+ok+=+SetDllDirectory(path);
++++++++if+(!ok)+throw+new+System.ComponentModel.Win32Exception();
++++}
++++[DllImport("kernel32.dll",+CharSet+=+CharSet.Auto,+SetLastError+=+true)]
++++private+static+extern+bool+SetDllDirectory(string+path);
}|code-block|syntax|javascript|1939337|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

In this case, i should do like this (make 2 folders, x64 and x86 + put the corresponding dll, WITH THE SAME NAME, in both folders):

<pre><code>using System;
using System.Runtime.InteropServices;
using System.Reflection;
using System.IO;

class Program {
 static void Main(string[] args) {
 var path = Path.GetDirectoryName(Assembly.GetEntryAssembly().Location);
 path = Path.Combine(path, IntPtr.Size == 8 ? "x64" : "x86");
 bool ok = SetDllDirectory(path);
 if (!ok) throw new System.ComponentModel.Win32Exception();
 }
 [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
 private static extern bool SetDllDirectory(string path);
}
</code></pre>

blocks|key|1939398|text|另一种方法可能是|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1939399|public+static+class+Sample
{
++++public+Sample()
++++{

++++++++string+StartupDirEndingWithSlash+=+System.IO.Path.GetDirectoryName(System.Diagnostics.Process.GetCurrentProcess().MainModule.FileName)+%2B+"\\";
++++++++string+ResolvedDomainTimeFileName+=+StartupDirEndingWithSlash+%2B+"ABCLib_Resolved.dll";
++++++++if+(!File.Exists(ResolvedDomainTimeFileName))
++++++++{
++++++++++++if+(Environment.Is64BitProcess)
++++++++++++{
++++++++++++++++if+(File.Exists(StartupDirEndingWithSlash+%2B+"ABCLib_64.dll"))
++++++++++++++++++++File.Copy(StartupDirEndingWithSlash+%2B+"ABCLib_64.dll",+ResolvedDomainTimeFileName);
++++++++++++}
++++++++++++else
++++++++++++{
++++++++++++++++if+(File.Exists(StartupDirEndingWithSlash+%2B+"ABCLib_32.dll"))
++++++++++++++++++++File.Copy(StartupDirEndingWithSlash+%2B+"ABCLib_32.dll",+ResolvedDomainTimeFileName);
++++++++++++}
++++++++}
++++}

++++[DllImport("ABCLib__Resolved.dll")]
++++private+static+extern+bool+SomeFunctionName(ref+int+FT);
}|code-block|syntax|javascript|1939400|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

an alternative approach may be 

<pre><code>public static class Sample
{
 public Sample()
 {

 string StartupDirEndingWithSlash = System.IO.Path.GetDirectoryName(System.Diagnostics.Process.GetCurrentProcess().MainModule.FileName) + "\\";
 string ResolvedDomainTimeFileName = StartupDirEndingWithSlash + "ABCLib_Resolved.dll";
 if (!File.Exists(ResolvedDomainTimeFileName))
 {
 if (Environment.Is64BitProcess)
 {
 if (File.Exists(StartupDirEndingWithSlash + "ABCLib_64.dll"))
 File.Copy(StartupDirEndingWithSlash + "ABCLib_64.dll", ResolvedDomainTimeFileName);
 }
 else
 {
 if (File.Exists(StartupDirEndingWithSlash + "ABCLib_32.dll"))
 File.Copy(StartupDirEndingWithSlash + "ABCLib_32.dll", ResolvedDomainTimeFileName);
 }
 }
 }

 [DllImport("ABCLib__Resolved.dll")]
 private static extern bool SomeFunctionName(ref int FT);
}
</code></pre>

blocks|key|1725945|text|我认为这有助于动态加载DLL：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1725946|+++#if+X64++++
++++[DllImport("MyDll64.dll",+CallingConvention=CallingConvention.Cdecl,+EntryPoint=Func1")]
++++#else
++++[DllImport("MyDll32.dll",+CallingConvention=CallingConvention.Cdecl,+EntryPoint=Func1")]
++++#endif
++++private+static+extern+int+is_Func1(int+var1,+int+var2);|code-block|syntax|javascript|1725947|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I think this could help to load the DLL dynamically: 

<pre><code> #if X64 
 [DllImport("MyDll64.dll", CallingConvention=CallingConvention.Cdecl, EntryPoint=Func1")]
 #else
 [DllImport("MyDll32.dll", CallingConvention=CallingConvention.Cdecl, EntryPoint=Func1")]
 #endif
 private static extern int is_Func1(int var1, int var2);
</code></pre>

Here is the situation, I'm using a C based dll in my dot.net application. There are 2 dlls, one is 32bit called MyDll32.dll and the other is a 64bit version called MyDll64.dll.

There is a static variable holding the DLL file name: string DLL_FILE_NAME.

and it is used in the following way:

<pre><code>[DllImport(DLL_FILE_NAME, CallingConvention=CallingConvention.Cdecl, EntryPoint=Func1")]
private static extern int is_Func1(int var1, int var2);
</code></pre>

Simple so far.

As you can imagine, the software is compiled with "Any CPU" turned on.

I also have the following code to determine if the system should use the 64bit file or the 32bit file.

<pre><code>#if WIN64
 public const string DLL_FILE_NAME = "MyDll64.dll";
#else
 public const string DLL_FILE_NAME = "MyDll32.dll"; 
#endif
</code></pre>

By now you should see the problem.. DLL_FILE_NAME is defined in compilation time and not in execution time so the right dll isn't loaded according to the execution context.

What would be the correct way to deal with this issue? I do not want two execution files (one for 32bit and the other for 64bit)? How can I set DLL_FILE_NAME before it is used in the DllImport statement?

Using a 32bit or 64bit dll in C# DllImport

情况是这样的，我在dot.net应用程序中使用了一个基于C的动态链接库。有两个dll，一个是称为MyDll32.dll的32位版本，另一个是称为MyDll64.dll的64位版本。有一个静态变量保存着DLL文件名: string DLL_FILE_NAME。它的用法如下：[DllImport(DLL_FILE_NAME...

问在C# DllImport中使用32位或64位动态链接库
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