csdn_文档中心_vb与vc通信初探（一）.htm

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            <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=3><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"></SPAN></FONT>&nbsp;</P>
            <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=3><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">&nbsp;&nbsp;&nbsp; 
            在使用</SPAN><SPAN lang=EN-US>VB</SPAN><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">调用</SPAN><SPAN 
            lang=EN-US>VC</SPAN><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">写的</SPAN><SPAN 
            lang=EN-US>DLL</SPAN><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的时候，可以实现一些</SPAN><SPAN 
            lang=EN-US>VB</SPAN><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">不能实现或者很难实现的功能，但是，因为</SPAN><SPAN 
            lang=EN-US>VB</SPAN><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">与</SPAN><SPAN 
            lang=EN-US>VC</SPAN><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">之间的数据类型并不总是完全对应的，所以，在进行参数传递的时候，就需要进行类型转换了。下面我将通过逐步的推进的方法，来看看如何达到</SPAN><SPAN 
            lang=EN-US>VB</SPAN><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">与</SPAN><SPAN 
            lang=EN-US>VC</SPAN><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">之间的通信。</SPAN></FONT></P>
            <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
            lang=EN-US><FONT size=3>&nbsp;<?xml:namespace prefix = o ns = 
            "urn:schemas-microsoft-com:office:office" 
            /><o:p></o:p></FONT></SPAN></P>
            <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
            lang=EN-US><FONT size=3>&nbsp;<o:p></o:p></FONT></SPAN></P>
            <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"><FONT 
            size=3>&nbsp;&nbsp;&nbsp; 首先，看一个简单的例子。</FONT></SPAN></P>
            <BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=3><SPAN 
              lang=EN-US>VC</SPAN><SPAN 
              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">中的程序：</SPAN></FONT></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              lang=EN-US><FONT size=3>extern "C" _declspec(dllexport) void<SPAN 
              style="mso-spacerun: yes">&nbsp; 
              </SPAN>ReadString(void)</FONT></SPAN></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              lang=EN-US><FONT size=3>{</FONT></SPAN></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=3><SPAN 
              lang=EN-US>//</SPAN><SPAN 
              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">函数功能</SPAN></FONT></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              lang=EN-US><FONT size=3>}</FONT></SPAN></P></BLOCKQUOTE>
            <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
            lang=EN-US><FONT size=3>&nbsp;<o:p></o:p></FONT></SPAN></P>
            <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=3><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">&nbsp;&nbsp; 
            将这个</SPAN><SPAN lang=EN-US>VC</SPAN><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">程序编译成</SPAN><SPAN 
            lang=EN-US>DLL</SPAN><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">程序供</SPAN><SPAN 
            lang=EN-US>VB</SPAN><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">调用（假设生成的为</SPAN><SPAN 
            lang=EN-US>commication.dll</SPAN><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">）</SPAN></FONT></P>
            <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
            lang=EN-US><FONT size=3>&nbsp;<o:p></o:p></FONT></SPAN></P>
            <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=3><SPAN 
            lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp; VB</SPAN><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">中的程序：</SPAN></FONT></P>
            <BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"><FONT 
              size=3>……………………</FONT></SPAN></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              lang=EN-US><FONT size=3>Private Declare Function ReadString Lib 
              "commication.dll" () </FONT></SPAN></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"><FONT 
              size=3>……………………</FONT></SPAN></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              lang=EN-US><FONT size=3>call 
            ReadString</FONT></SPAN></P></BLOCKQUOTE>
            <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
            lang=EN-US><FONT size=3>&nbsp;<o:p></o:p></FONT></SPAN></P>
            <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=3><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">&nbsp;&nbsp;&nbsp;&nbsp; 
            在这里，我们实现了一个简单的通信，即在</SPAN><SPAN lang=EN-US>VC</SPAN><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">中写了一个</SPAN><SPAN 
            lang=EN-US>DLL,</SPAN><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">然后再在</SPAN><SPAN 
            lang=EN-US>VB</SPAN><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">中调用了这个</SPAN><SPAN 
            lang=EN-US>DLL,</SPAN><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">但是，在这次的通信中，实际上他们之间没有传递任何数据，仅仅是</SPAN><SPAN 
            lang=EN-US>VB</SPAN><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">调用了</SPAN><SPAN 
            lang=EN-US>DLL,</SPAN><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">从而使得</SPAN><SPAN 
            lang=EN-US>commication.dll</SPAN><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">中的函数</SPAN><SPAN 
            lang=EN-US>ReadString()</SPAN><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">函数执行。这种通信实现是非常简单，所以他完成的功能也就非常的简单，然而我们的要求肯定不止于此。</SPAN></FONT></P>
            <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
            lang=EN-US><FONT size=3>&nbsp;<o:p></o:p></FONT></SPAN></P>
            <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
            lang=EN-US><FONT size=3>&nbsp;<o:p></o:p></FONT></SPAN></P>
            <P class=MsoNormal dir=ltr style="MARGIN: 0cm 0cm 0pt"><FONT 
            size=3><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">&nbsp;&nbsp;&nbsp; 
            现在就让我们来实现一个使用</SPAN><SPAN lang=EN-US>DLL</SPAN><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">来处理</SPAN><SPAN 
            lang=EN-US>VB</SPAN><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">中的数据的例子，并且将处理结果返回给</SPAN><SPAN 
            lang=EN-US>VB</SPAN><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">程序：</SPAN></FONT></P>
            <BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=3><SPAN 
              lang=EN-US>VC</SPAN><SPAN 
              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">中的程序：</SPAN></FONT></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              lang=EN-US><FONT size=3>extern "C" _declspec(dllexport) bool<SPAN 
              style="mso-spacerun: yes">&nbsp; </SPAN>ReadString(bool 
              receive)</FONT></SPAN></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              lang=EN-US><FONT size=3>{</FONT></SPAN></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              lang=EN-US><FONT size=3>&nbsp;<o:p></o:p></FONT></SPAN></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              lang=EN-US><FONT size=3>if(receive==true)</FONT></SPAN></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              lang=EN-US><FONT size=3><SPAN 
              style="mso-spacerun: yes">&nbsp;</SPAN>return 
              true;</FONT></SPAN></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              lang=EN-US><FONT size=3>else </FONT></SPAN></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              lang=EN-US><FONT size=3><SPAN 
              style="mso-spacerun: yes">&nbsp;</SPAN>return 
              false;</FONT></SPAN></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              lang=EN-US><FONT size=3>}</FONT></SPAN></P></BLOCKQUOTE>
            <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
            lang=EN-US><FONT size=3>&nbsp;<o:p></o:p></FONT></SPAN></P>
            <BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=3><SPAN 
              lang=EN-US>VB</SPAN><SPAN 
              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">中的程序：</SPAN></FONT></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"><FONT 
              size=3>……………………</FONT></SPAN></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              lang=EN-US><FONT size=3>Private Declare Function ReadString Lib 
              "commication.dll" (ByVal send As Boolean) as 
              Boolean</FONT></SPAN></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'"><FONT 
              size=3>……………………</FONT></SPAN></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              lang=EN-US><FONT size=3>Dim result As Boolean</FONT></SPAN></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              lang=EN-US><FONT size=3>Dim send As Boolean</FONT></SPAN></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              lang=EN-US><FONT size=3>&nbsp;<o:p></o:p></FONT></SPAN></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              lang=EN-US><FONT size=3>send = False</FONT></SPAN></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              lang=EN-US><FONT size=3>&nbsp;<o:p></o:p></FONT></SPAN></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              lang=EN-US><FONT size=3>result = 
ReadString(send)</FONT></SPAN></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              lang=EN-US><FONT size=3>&nbsp;<o:p></o:p></FONT></SPAN></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              lang=EN-US><FONT size=3>If result Then</FONT></SPAN></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              lang=EN-US><FONT size=3><SPAN 
              style="mso-spacerun: yes">&nbsp;</SPAN>MsgBox "The return value is 
              'true'"</FONT></SPAN></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              lang=EN-US><FONT size=3>Else</FONT></SPAN></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              lang=EN-US><FONT size=3><SPAN 
              style="mso-spacerun: yes">&nbsp;</SPAN>MsgBox "The return value is 
              'false'"</FONT></SPAN></P>
              <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
              lang=EN-US><FONT size=3>End If</FONT></SPAN></P></BLOCKQUOTE>
            <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><SPAN 
            lang=EN-US><FONT size=3>&nbsp;<o:p></o:p></FONT></SPAN></P>
            <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT size=3><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">&nbsp;&nbsp;&nbsp; 
            在这次的通信过程中，我们还是实现了一个很简单的通行过程，在</SPAN><SPAN lang=EN-US>DLL</SPAN><SPAN 
            style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">中，根据</SPAN><SPAN