使用PInvoke註冊表函數，如何從句柄指針獲取數據？

Question

說我使用的RegQueryValueEx：

http://msdn.microsoft.com/en-us/library/ms724911(v=VS.85).aspx

我能得到的指針句柄lpType，但它只是一個整數，我如何真正得到的數據lpType指向？

Answer 1

As it clearly tells says on MSDN它只是一個整數...它只是一個從0到7的枚舉，其中0是REG_NONE ... 7是REG_MULTI_SZ。檢查出here for more detail查看關鍵類型。

Answer 2

'lpType'不指向實際數據，實際數據返回'lpData'參數中。

Answer 3

logicnp是正確的。

m0s有正確的想法，但我會爭論該MSDN鏈接的清晰度。 lpType實際上應該是無符號整數類型。我決定做一個枚舉爲我自己的理智：

/// <summary>Specify the data type to retrieve from the registry</summary> 
    /// <remarks> https://msdn.microsoft.com/en-us/library/windows/desktop/ms724884%28v=vs.85%29.aspx </remarks> 
    public enum RegDataType 
    { 
     /// <summary>[0] No defined value type.</summary> 
     REG_NONE, 

     /// <summary>[1] Null-terminated string. 
     /// It will be a Unicode or ANSI string, depending on whether you use the Unicode or ANSI functions.</summary> 
     REG_SZ, 

     /// <summary>[2] Null-terminated string that contains unexpanded references to environment variables (for example, "%PATH%"). 
     /// It will be a Unicode or ANSI string, depending on whether you use the Unicode or ANSI functions.</summary> 
     REG_EXPAND_SZ, 

     /// <summary>[3] Binary data in any form.</summary> 
     REG_BINARY, 

     /// <summary>[4] 32-bit number.</summary> 
     REG_DWORD, 

     /* /// <summary> [4] 32-bit number in little-Endean format. This is equivalent to REG_DWORD. 
      /// In little-Endean format, a multi-byte value is stored in memory from the lowest byte (the "little end") to the highest byte. 
      //// For example, the value 0x12345678 is stored as (0x78 0x56 0x34 0x12) in little-Endean format.</summary> 
     */ //REG_DWORD_LITTLE_ENDIAN 4 

     /// <summary>[5] 32-bit number in big-Endean format. 
     /// In big-Endean format, a multi-byte value is stored in memory from the highest byte (the "big end") to the lowest byte. 
     /// For example, the value 0x12345678 is stored as (0x12 0x34 0x56 0x78) in big-Endean format.</summary> 
     REG_DWORD_BIG_ENDIAN, 

     /// <summary>[6]Unicode symbolic link.</summary> 
     REG_LINK, 

     /// <summary>[7] Array of null-terminated strings that are terminated by two null characters.</summary> 
     REG_MULTI_SZ, 

     /// <summary>[8]Device-driver resource list.</summary> 
     REG_RESOURCE_LIST, 

     /// <summary>[9] </summary> 
     REG_FULL_RESOURCE_DESCRIPTOR, 

     /// <summary>[10] </summary> 
     REG_RESOURCE_REQUIREMENTS_LIST, 

     /// <summary>[11] 64-bit number.</summary> 
     REG_QWORD 

     /* /// <summary>[11] A 64-bit number in little-Endean format. This is equivalent to REG_QWORD.</summary> 
     */ //REG_QWORD_LITTLE_ENDIAN 11 
    } 

一旦你的，你可以通過數據類型轉換，封送指針結果，並根據類型轉換。由於您無法直接編組爲無符號類型，因此您也需要考慮這一點。 不要忘記錯誤處理。

段：

switch ((Enums.RegDataType)type) 
    { 
     case Enums.RegDataType.REG_SZ: 
      return Marshal.PtrToStringAnsi(pResult); 

     case Enums.RegDataType.REG_DWORD: 
       int DWORDCouldBeNegative = Marshal.ReadInt32(pResult); 
       uint DWORDCastBackToUInt = (uint)DWORDCouldBeNegative; 
       return DWORDCastBackToUInt.ToString(); 

     case Enums.RegDataType.REG_QWORD: 
       Int64 QWORDCouldBeNegative = Marshal.ReadInt64(pResult); 
       UInt64 QWORDCastBackToUInt = (UInt64)QWORDCouldBeNegative; 
       return QWORDCastBackToUInt.ToString(); 

     case Enums.RegDataType.REG_BINARY: ...