COM应用总结(2/3) c++实例和部署

接着把这个总结继续。

实例

以常用的HTML文档的处理为例，深入地描述一下COM的使用，其他的类别使用类同（如Office的编程对象）

首先工程包含

#include <mshtml.h>

具体的代码如下：

//以DOM对象的形式遍历HTML文档
int WalkTree(CComPtr<IHTMLDOMNode> domNode)
{
    ASSERT(domNode!=NULL);

    long type;
    CComBSTR tag;
    if(domNode->get_nodeType(&type)==S_OK)
    {
        switch(type)
        {
        case 1://MSXML::NODE_ELEMENT:
            {
                // Get the element name and set the tag name...
                if(SUCCEEDED(domNode->get_nodeName(&tag)) )
                {
                    ///查到 <a ... 这样的元素                    if(wcscmp(tag.m_str, L"A")==0)
                    {
                        CComPtr<IDispatch> pDisp;
                        domNode->get_attributes(&pDisp);

                        CComQIPtr<IHTMLAttributeCollection, &IID_IHTMLAttributeCollection> pAttrs;
                        pAttrs = pDisp;
                        pDisp = NULL;

                        long l;
                        COleVariant index;
                        index.vt = VT_I4;
                        pAttrs->get_length(&l);
                        for (long i = 0; i < l; i++)
                        {
                            pDisp = NULL;
                            index.lVal = i;
                            pAttrs->item(index, &pDisp);

                            ///查询接口 也可用 CComQIPtr
                            CComPtr<IHTMLDOMAttribute> phref;
                            if(SUCCEEDED(pDisp->QueryInterface(IID_IHTMLDOMAttribute, (void**)&phref)) )
                            {
                                VARIANT_BOOL vbSpecified;
                                phref->get_specified(&vbSpecified);
                                if(VARIANT_TRUE==vbSpecified)
                                {
                                    CComBSTR text;
                                    if(SUCCEEDED(phref->get_nodeName(&text)) )
                                    {
                                        ///You can do...
                                    }

                                    COleVariant v;
                                    if(SUCCEEDED(phref->get_nodeValue(&v)) )
                                    {
                                        ///You can do...
                                    }
                                }
                            }
                        }
                    }
                }           

                CComPtr<IHTMLDOMNode> pChild;
                if(domNode->get_firstChild(&pChild)==S_OK)
                {
                    // If we have children, loop through and handle each one...
                    if (pChild)
                    {
                        // Recurse for all the children of this tag...
                        CComPtr<IHTMLDOMNode> domChild;
                        while (pChild)
                        {
                            WalkTree(pChild);

                            domChild=NULL;
                            domChild=pChild;
                            pChild=NULL;
                            domChild->get_nextSibling(&pChild);
                        }
                    }
                }
                break;
            }
        case 3://MSXML::NODE_TEXT:
            {
                COleVariant val;
                if(domNode->get_nodeValue(&val)==S_OK)
                {
                    ///You can do...
                }
            }
            break;
        }
    }

    return 0;
}

void CBrowserDomDlg::OnBnClickedOk()
{
    CComPtr<IDispatch> pDisp;
    pDisp = m_Web.get_Document();

    CComQIPtr<IHTMLDocument2, &IID_IHTMLDocument2> pHTML;
    pHTML = pDisp;

    ///可以查看HTML的 title内容
    CComBSTR bstrTitle;
    if(pHTML!=NULL && pHTML->get_title(&bstrTitle)==S_OK)
    {
        //title is
    }

    CComPtr<IHTMLElementCollection> pElems;
    HRESULT hr;

    pHTML->get_all(&pElems);
    if(pElems==NULL) return;
    long l;
    if(!SUCCEEDED(pElems->get_length(&l)) )
        return;

    //遍历元素找到BODY节点
    CComPtr<IHTMLElement> htmlBody;   
    COleVariant index;
    for(int i=0;i<l;i++)
    {
        CComPtr<IDispatch> pChild;

        index.vt = VT_I4;
        index.lVal = i;

        hr=pElems->item(index,index ,&pChild);
        htmlBody=NULL;
        if(SUCCEEDED(hr) && SUCCEEDED(pChild.QueryInterface(&htmlBody)) && htmlBody!=NULL)
        {
            CComBSTR name;
            hr=htmlBody->get_tagName(&name);
            if(wcscmp(name.m_str, L"BODY")==0)
                break;
        }
    }

    if(htmlBody==NULL) return;

    CComPtr<IHTMLDOMNode>pDOM;
    htmlBody->QueryInterface(&pDOM);

    if(pDOM==NULL) return;

    WalkTree(pDOM);
}

还有我们在应用中常用的ADO数据存取的方式：

#import   "C:\Program   Files\common   files\system\ado\msado15.dll "   no_namespace   rename( "EOF ", "EndOfFile ")   rename( "BOF ", "FirstOfFile ")

_RecordsetPtr   m_pRs;

具体的操作和以上的例子类似

部署

一般的COM组件都是C++开发的[因为现在.net提供了更好的实现形式,单纯使用COM的时机少了很多]，部署时只要注意对应的MFC库和ATL库的设置即可

部署有两个形式[在项目编译选项设置]：

全部的实例代码参见：

http://cid-56b433ad3d1871e3.office.live.com/self.aspx/.Public/ComTutorial.zip