Question

我想使用kernel32.dll并且需要为此创建我自己的dll我创建了DllImp.cs代码，并希望在另一个文件中使用这些方法，例如pipe.cs，但是我收到的错误如

CreateNamedPipe is a method but is used like a type.
PipeName is a field but is used like a type
PIPE_ACCESS_DUPLEX is a field but is used like a type
PIPE_TYPE_MESSAGE  is a field but is used like a type

我的代码是：

//DllImp.cs code
using System;
using System.Text;
using System.Security;
using System.Runtime.InteropServices;

namespace MessageManagerServer {
[SuppressUnmanagedCodeSecurity]
public sealed class DllImports {
           [DllImport("kernel32.dll")]
    public static extern IntPtr CreateNamedPipe(
        String lpName,                              // pipe name
        uint dwOpenMode,                            // pipe open mode
        uint dwPipeMode,                            // pipe-specific modes
        uint nMaxInstances,                         // maximum number of instances
        uint nOutBufferSize,                        // output buffer size
        uint nInBufferSize,                         // input buffer size
        uint nDefaultTimeOut,                       // time-out interval
        IntPtr pipeSecurityDescriptor);             // SD
  public const uint PIPE_ACCESS_DUPLEX       = 0x00000003;
    //public const uint PIPE_TYPE_BYTE           = 0x00000000;
    public const uint PIPE_TYPE_MESSAGE        = 0x00000004;
    //public const uint PIPE_READMODE_BYTE       = 0x00000000;
    public const uint PIPE_READMODE_MESSAGE    = 0x00000002;
    public const uint PIPE_WAIT                = 0x00000000;

    public const uint NMPWAIT_WAIT_FOREVER     = 0xffffffff;
    public const uint NMPWAIT_USE_DEFAULT_WAIT = 0x00000000;

    public const int  INVALID_HANDLE_VALUE     = -1;
    public const uint ERROR_IO_PENDING         = 997;
    public const uint PIPE_UNLIMITED_INSTANCES = 255;

    public DllImp() {
    }
}

这是pipe.cs代码

using System;
using System.Text;
using System.Security;
using System.Runtime.InteropServices;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Collections;
using System.Data;
using System.IO;
using System.Data.SqlClient;
using System.Xml;
using System.Windows.Forms;
using System.Diagnostics;

namespace ClassLibrary1
{
public class Pipe
{
    private string PipeName = "\\\\.\\pipe\\Honeywell";
    public IntPtr Handle;
    Handle = DllImp.CreateNamedPipe(PipeName,DllImp.PIPE_ACCESS_DUPLEX,
                               DllImp.PIPE_TYPE_MESSAGE     |         
                               DllImp.PIPE_READMODE_MESSAGE |         
                               DllImp.PIPE_WAIT,                      
                               1,                                        
                               0,                                         
                               0,                                        
                               1000,                                      
                               IntPtr.Zero);

}
}

Answer 1

你不能像这样初始化Handle字段，你在初始化期间尝试访问实例字段：

 public IntPtr Handle;
 Handle = ...

这是不允许的，因为您可能在初始化之前访问该字段。

尝试一次性完成所有操作：

public IntPtr Handle = DllImp.CreateNamedPipe(PipeName,DllImp.PIPE_ACCESS_DUPLEX,
                           DllImp.PIPE_TYPE_MESSAGE     |         
                           DllImp.PIPE_READMODE_MESSAGE |         
                           DllImp.PIPE_WAIT,                      
                           1,                                        
                           0,                                         
                           0,                                        
                           1000,                                      
                           IntPtr.Zero);

您也可以将初始化移动到类构造函数中，就像在Marcs回答中一样，这是更清洁的IMO。

public Pipe()
{
    Handle = ....
}

Answer 2

嗯，我：

将所有DllImp更改为DllImports（因为这就是该类的名称）
将Handle =代码移动到构造函数中（也可能使用了字段初始化程序，但这似乎保留了代码的意图）

它编译得很好。

public Pipe()
{
    Handle = DllImports.CreateNamedPipe(PipeName,
                       DllImports.PIPE_ACCESS_DUPLEX,
                       DllImports.PIPE_TYPE_MESSAGE |
                       DllImports.PIPE_READMODE_MESSAGE |
                       DllImports.PIPE_WAIT,
                       1,
                       0,
                       0,
                       1000,
                       IntPtr.Zero);
}

（也将DllImports中的构造函数重命名为DllImports）

完整代码：http://pastie.org/8555683

调用一个DLL方法，但它说“是一个字段，但像一个类型一样使用”

2 个答案: