c++之WMI编程

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大家平时在用类似鲁大师之类软件的时候，会看到鲁大师之类的软件能够获取到PC机的硬件的详细信息，有时候自己在写软件的时候也需要获取PC硬件的详细信息，这个时候你会发现有的硬件信息通过系统的API函数无法获取到或者获取的不准确。所以这个时候就要通过WMI编程来获取硬件信息了。WMI是windows操作系统用来管理软件和硬件的核心。其它的不再多讲了，下面来看最主要的，通过WMI获取硬件信息。

整体来说，通过WMI获取计算机硬件信息有以下几个步骤

1、用CoInitializeEx函数初始化COM参数。因为WMI中的类都是基于COM技术的。

2、用CoInitializeSecurity函数初始化COM进程的安全，因为WMI的进程和应用程序进程不在同一个级别。

3、获取IWbemServices指针，通过函数IWbemLocator::ConnectServer获取。

4、通过CoSetProxyBlanket设置IWbemServices代理安全，使WMI服务可以模拟客户端。

5、使用IWbemServices进行WMI查询，主要使用WQL语句。

6、清理COM对象。

例子，查询操作系统信息的一个例子

1 #include "stdafx.h"
  2 #include <iostream>
  3 using namespace std;
  4 #include <comdef.h>
  5 #include <Wbemidl.h>
  6 # pragma comment(lib, "wbemuuid.lib")
  7 int _tmain( int argc, _TCHAR* argv[])
  8 {
  9
10
11     HRESULT hres;
12
13      // Initialize COM.
14     hres =  CoInitializeEx(0, COINIT_MULTITHREADED);
15      if (FAILED(hres))
16     {
17         cout << "Failed to initialize COM library. "
18             << "Error code = 0x"
19             << hex << hres << endl;
20          return 1;               // Program has failed.
21     }
22
23      // Initialize
24     hres =  CoInitializeSecurity(
25         NULL,
26         -1,       // COM negotiates service
27         NULL,     // Authentication services
28         NULL,     // Reserved
29         RPC_C_AUTHN_LEVEL_DEFAULT,     // authentication
30         RPC_C_IMP_LEVEL_IMPERSONATE,   // Impersonation
31         NULL,              // Authentication info
32         EOAC_NONE,         // Additional capabilities
33         NULL               // Reserved
34         );
35      if (FAILED(hres))
36     {
37         cout << "Failed to initialize security. "
38             << "Error code = 0x"
39             << hex << hres << endl;
40         CoUninitialize();
41          return 1;           // Program has failed.
42     }
43
44      // Obtain the initial locator to Windows Management
45      // on a particular host computer.
46     IWbemLocator *pLoc = 0;
47
48     hres = CoCreateInstance(
49         CLSID_WbemLocator,
50         0,
51         CLSCTX_INPROC_SERVER,
52         IID_IWbemLocator, (LPVOID *) &pLoc);
53
54      if (FAILED(hres))
55     {
56         cout << "Failed to create IWbemLocator object. "
57             << "Error code = 0x"
58             << hex << hres << endl;
59         CoUninitialize();
60          return 1;        // Program has failed.
61     }
62
63     IWbemServices *pSvc = 0;
64
65      // Connect to the root\cimv2 namespace with the
66      // current user and obtain pointer pSvc
67      // to make IWbemServices calls.
68
69     hres = pLoc->ConnectServer(
70
71         _bstr_t(L"ROOT\\CIMV2"), // WMI namespace
72         NULL,                     // User name
73         NULL,                     // User password
74         0,                        // Locale
75         NULL,                     // Security flags
76         0,                        // Authority
77         0,                        // Context object
78         &pSvc                     // IWbemServices proxy
79         );
80
81      if (FAILED(hres))
82     {
83         cout << "Could not connect. Error code = 0x"
84             << hex << hres << endl;
85         pLoc->Release();
86         CoUninitialize();
87          return 1;                 // Program has failed.
88     }
89
90     cout << "Connected to ROOT\\CIMV2 WMI namespace" << endl;
91
92      // Set the IWbemServices proxy so that impersonation
93      // of the user (client) occurs.
94     hres = CoSetProxyBlanket(
95
96         pSvc,                          // the proxy to set
97         RPC_C_AUTHN_WINNT,             // authentication service
98         RPC_C_AUTHZ_NONE,              // authorization service
99         NULL,                          // Server principal name
100         RPC_C_AUTHN_LEVEL_CALL,        // authentication level
101         RPC_C_IMP_LEVEL_IMPERSONATE,   // impersonation level
102         NULL,                          // client identity
103         EOAC_NONE                      // proxy capabilities
104         );
105
106      if (FAILED(hres))
107     {
108         cout << "Could not set proxy blanket. Error code = 0x"
109             << hex << hres << endl;
110         pSvc->Release();
111         pLoc->Release();
112         CoUninitialize();
113          return 1;                // Program has failed.
114     }
115
116     IEnumWbemClassObject* pEnumerator = NULL;
117     hres = pSvc->ExecQuery(
118         bstr_t("WQL"),
119         bstr_t("SELECT * FROM Win32_OperatingSystem"), //此处wql语句更改，实现不同的查询
120         WBEM_FLAG_FORWARD_ONLY | WBEM_FLAG_RETURN_IMMEDIATELY,
121         NULL,
122         &pEnumerator);
123
124      if (FAILED(hres))
125     {
126         cout << "Query for processes failed. "
127             << "Error code = 0x"
128             << hex << hres << endl;
129         pSvc->Release();
130         pLoc->Release();
131         CoUninitialize();
132          return 1;                // Program has failed.
133     }
134      else
135     {
136         IWbemClassObject *pclsObj;
137         ULONG uReturn = 0;
138
139          while (pEnumerator)
140         {
141             hres = pEnumerator->Next(WBEM_INFINITE, 1,
142                 &pclsObj, &uReturn);
143
144              if(0 == uReturn)
145             {
146                  break;
147             }
148
149             VARIANT vtProp;
150
151              // Get the value of the Name property
152             hres = pclsObj->Get(L" Name", 0, &vtProp, 0, 0); //此处把Name改成对应的要获取的属性值
153             wcout << "Manufacturer Name : " << vtProp.bstrVal << endl;
154             VariantClear(&vtProp);
155         }
156
157     }
158
159      // Cleanup
160      // ========
161
162     pSvc->Release();
163     pLoc->Release();
164     CoUninitialize();
165      return 0;
166 }
167

c++之WMI编程

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