我有一个C＃dll，想在VB.NET中使用它。我正在使用C＃2008 Express和VB 2008 Express。我在VB项目中添加了一个引用到C＃dll。当我在C＃dll中创建一个类的instane时，它会给出以下错误消息：“Type'RF.RabinFingerprint'没有构造函数”。我该如何解决这个问题？
我的C＃DLL代码：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace RF
{
/// <summary>
/// Génère des empreintes de fichiers
/// </summary>
public static class RabinFingerprint
{
/// <summary>
/// Bit 64 of the polynomial P is always 1 and not treated directly. This is the polynomial
/// with the leading coefficient removed (lcr).
/// Represents t^64 + t^4 + t^3 + t + 1.
/// </summary>
private static readonly UInt64 p_lcr = 0x000000000000001BL;
/// <summary>
/// It's not necessary to provide definitions for such integral constant variables as long as their
/// addresses are not taken.
/// Degree of the polynomial P.
/// </summary>
private static readonly int K = 64;
/// <summary>
/// Represents t^(K-1)
/// </summary>
private static readonly UInt64 T_K_minus_1 = (UInt64)1L << (K - 1);
/// <summary>
/// Broder's paper presents four pre-computed tables because words are considered to be 32-bit.
/// In this implementation W is a 64-bit integral type. Eight tables are used.
/// Table A is i1^127 + i2^126 + ... + i8^120.
/// Table B is i1^119 + i2^118 + ... + i8^112.
/// Table C, D, ..
/// Table E is i1^95 + i2^94 + ... + i8^88. (This is table A in the paper.)
/// Table F, G, H.
/// </summary>
private static UInt64[] tableA_ = new UInt64[256]; //Assuming byte size 8.
private static UInt64[] tableB_ = new UInt64[256];
private static UInt64[] tableC_ = new UInt64[256];
private static UInt64[] tableD_ = new UInt64[256];
private static UInt64[] tableE_ = new UInt64[256];
private static UInt64[] tableF_ = new UInt64[256];
private static UInt64[] tableG_ = new UInt64[256];
private static UInt64[] tableH_ = new UInt64[256];
/// <summary>
/// Constructor
/// </summary>
static RabinFingerprint()
{
InitTables();
}
/// <summary>
/// Initialize tables
/// </summary>
private static void InitTables()
{
//This represents t^(k + i) mod P, where i is the index of the array.
//It will be used to compute the tables.
UInt64[] mods = new UInt64[K];
//Remember t^k mod P is equivalent to p_lcr.
mods[0] = p_lcr;
for (int i = 1; i < K; ++i)
{
//By property: t^i mod P = t(t^(i - 1)) mod P.
mods[i] = mods[i - 1] << 1;
//If mods[i - 1] had a term at k-1, mods[i] would have had the term k, which is not represented.
//The term k would account for exactly one more division by P. Then, the effect is the same
//as adding p_lcr to the mod.
if ((mods[i - 1] & T_K_minus_1) != 0)
mods[i] ^= p_lcr;
}
//Compute tables. A control variable is used to indicate whether the current bit should be
//considered.
for (int i = 0; i < 256; ++i)
{
int control = i;
for (int j = 0; j < 8 && control > 0; ++j)
{
// bool.Parse(Convert.ToString())
if ((control & 1) == 1) //Ok, consider bit. ((byte))
{
tableA_[i] ^= mods[j + 56];
tableB_[i] ^= mods[j + 48];
tableC_[i] ^= mods[j + 40];
tableD_[i] ^= mods[j + 32];
tableE_[i] ^= mods[j + 24];
tableF_[i] ^= mods[j + 16];
tableG_[i] ^= mods[j + 8];
tableH_[i] ^= mods[j];
}
control >>= 1;
}
}
}
/// <summary>
/// Compute hash key
/// </summary>
/// <param name="value">Value to hash</param>
/// <returns>Value</returns>
private static UInt64 ComputeTablesSum(ref UInt64 value)
{
value = tableH_[((value) & 0xFF)] ^
tableG_[((value >> 8) & 0xFF)] ^
tableF_[((value >> 16) & 0xFF)] ^
tableE_[((value >> 24) & 0xFF)] ^
tableD_[((value >> 32) & 0xFF)] ^
tableC_[((value >> 40) & 0xFF)] ^
tableB_[((value >> 48) & 0xFF)] ^
tableA_[((value >> 56) & 0xFF)];
return value; //Pass by reference to return the same w. (Convenience and efficiency.)
}
/// <summary>
/// Compute hask hey
/// </summary>
/// <param name="HashArray">Array of Ulong bytes to ahsh</param>
/// <returns>Hash key</returns>
private static UInt64 Compute(UInt64[] HashArray)
{
UInt64 w = 0L;
for (int s = 0; s < HashArray.Length; ++s)
w = ComputeTablesSum(ref w) ^ HashArray[s];
return w;
}
/// <summary>
/// Compute the fingerprint
/// </summary>
/// <param name="source">String to compute</param>
/// <returns>Hash key</returns>
public static UInt64 ComputeFingerPrint(string source)
{
byte[] table = Encoding.Unicode.GetBytes(source);
UInt64[] values = new UInt64[table.LongLength];
ConvertBytes(ref table, ref values);
return Compute(values);
}
/// <summary>
/// Compute the fingerprint, you must use this method for very large text
/// </summary>
/// <param name="source">String to compute</param>
/// <returns>Hash key</returns>
public static UInt64 ComputeFingerPrint(ref string source)
{
return ComputeFingerPrint(source);
}
/// <summary>
/// Compute the fingerprint, you must use this method for very large binary data
/// </summary>
/// <param name="source">Data to compute</param>
/// <returns>Hash key</returns>
public static UInt64 ComputeFingerPrint(ref byte[] source)
{
UInt64[] values = new UInt64[source.LongLength];
ConvertBytes(ref source, ref values);
return Compute(values);
}
/// <summary>
/// Compute the fingerprint, you must use this method for very large binary data
/// </summary>
/// <param name="source">Data to compute</param>
/// <returns>Hash key</returns>
public static UInt64 ComputeFingerPrint(byte[] source)
{
return ComputeFingerPrint(ref source);
}
/// <summary>
/// Compute byte array to Uint64 array
/// </summary>
/// <param name="source">Table de byte source</param>
/// <param name="destination">Tableau de Uin64</param>
private static void ConvertBytes(ref byte[] source, ref UInt64[] destination)
{
for (long i = 0; i < source.LongLength; i++)
destination[i] = Convert.ToUInt64(source[i]);
}
}
}
我的VB代码：
Imports RF
Module Module1
Sub Main()
Dim t As New RabinFingerprint
End Sub
End Module
答案 0 :(得分：7)
如果要使用实例，则需要向C＃类添加非静态构造函数 - 目前它只有静态构造函数。
有关VB.Net和C＃here中静态/共享之间的差异的信息可能有助于解决这个问题。
如果你在C＃中这样做，你只需要调用类的静态方法，如
UInt64 result = RabinFingerprint.ComputeFIngerprint(...);
等。
在VB.Net中，这看起来像这样：
Dim result = RF.RabinFingerprint.ComputeFingerprint(...)
这是我的意思example from MSDN。这里Console.WriteLine和Regex.Split都是静态的，就像你的类的方法一样。
Dim input As String = "plum--pear"
Dim pattern As String = "-" ' Split on hyphens
Dim substrings() As String = Regex.Split(input, pattern)
For Each match As String In substrings
Console.WriteLine("'{0}'", match)
Next
' The method writes the following to the console:
' 'plum'
' ''
' 'pear'
答案 1 :(得分：2)
您没有构造函数，因为您的类声明为静态
答案 2 :(得分：1)
您是否尝试过使用C＃？
它可能会给你带来同样的错误。
修改
我已经尝试过您的代码了。 （杰夫，我们需要 复制源代码按钮）
在VB.NET中。有以下错误：
Type 'RF.RabinFingerprint' has no constructors.
在C＃中，您会收到以下2个错误。
Cannot create an instance of the static class 'RF.RabinFingerprint'
Cannot declare a variable of static type 'RF.RabinFingerprint'
实际上C＃向您展示了真正的问题。正如爵士提到的那样。您应该将您的班级更改为非静态才能正常工作
<强> EDIT2
史蒂夫是对的。如果你的类被设计成静态的，因为它出现的东西都是静态的，那么必须改变的是对构造函数的调用。由于该类是静态的，因此无法创建类的实例。无需调用构造函数，因为它将在第一次使用类时自动调用（例如，当您从中调用方法时）。