hgfhhw 发表于 2007-8-9 21:52:00

请教大侠:如何将变量的值以字符串的形式显示

请教大侠,如何将变量的值在CAD绘图界面中以字符串的形式显示出来?

zhang007 发表于 2007-8-16 08:58:00

<p>这个问题涉及到变量的转换,各种类型变量转换成字符串方法不一样,转换成字符串后再添加数据库中,下面是添加文字的函数,如果你看不懂的话,多看多做ARX中SAMPLE下面的例子,多试几次..</p><p>AcDbObjectId&nbsp; createText(AcGePoint3d pt,CString strText,<br/>&nbsp;&nbsp;&nbsp;&nbsp;char *pStyleName,double Height,double dWidth,<br/>&nbsp;&nbsp;&nbsp;&nbsp;double rotation,char *pLayerName,AcDb::TextVertMode vMode,<br/>&nbsp;&nbsp;&nbsp;&nbsp;AcDb::TextHorzMode hMode)<br/>{<br/>&nbsp;AcDbTextStyleTable *pTextStyleTable;<br/>&nbsp;AcDbObjectId objId,styleId;<br/>&nbsp;char text;</p><p>&nbsp;&nbsp;&nbsp; acdbHostApplicationServices()-&gt;workingDatabase()<br/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; -&gt;getSymbolTable(pTextStyleTable, AcDb::kForRead);</p><p>&nbsp;if (!pTextStyleTable-&gt;has(pStyleName)){<br/>&nbsp;&nbsp;pTextStyleTable-&gt;close();<br/>&nbsp;&nbsp;createTextStyle(pStyleName,"romanc.shx","hzdx.shx",Height,1.0,0.0,1.0);<br/>&nbsp;&nbsp;&nbsp;&nbsp; acdbHostApplicationServices()-&gt;workingDatabase()<br/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; -&gt;getSymbolTable(pTextStyleTable, AcDb::kForRead);<br/>&nbsp;}<br/>&nbsp;if (pTextStyleTable-&gt;has(pStyleName)){<br/>&nbsp;&nbsp;pTextStyleTable-&gt;getAt(pStyleName,styleId,Adesk::kFalse);<br/>&nbsp;&nbsp;//′′?¨??×?<br/>&nbsp;&nbsp;AcDbBlockTable *pBlockTable;<br/>&nbsp;&nbsp;acdbHostApplicationServices()-&gt;workingDatabase()<br/>&nbsp;&nbsp;&nbsp;-&gt;getSymbolTable(pBlockTable,AcDb::kForRead);<br/>&nbsp;&nbsp;AcDbBlockTableRecord *pSpace;<br/>&nbsp;&nbsp;pBlockTable-&gt;getAt(ACDB_MODEL_SPACE,pSpace,AcDb::kForWrite);<br/>&nbsp;&nbsp;pBlockTable-&gt;close();</p><p>&nbsp;&nbsp;&nbsp; &nbsp;strcpy(text,strText);<br/>&nbsp;&nbsp;AcDbText *pText = new<br/>&nbsp;&nbsp;&nbsp;AcDbText(pt,text,styleId,Height,rotation);<br/>&nbsp;&nbsp;if(dWidth != 1.0)pText-&gt;setWidthFactor(dWidth);<br/>&nbsp;&nbsp;pText-&gt;setLayer(pLayerName);<br/>&nbsp;&nbsp;pText-&gt;setVerticalMode(vMode);<br/>&nbsp;&nbsp;pText-&gt;setHorizontalMode(hMode);<br/>&nbsp;&nbsp;pText-&gt;setAlignmentPoint(pt);<br/>&nbsp;&nbsp;pSpace-&gt;appendAcDbEntity(objId,pText);<br/>&nbsp;&nbsp;pText-&gt;close();<br/>&nbsp;&nbsp;pSpace-&gt;close();<br/>&nbsp;&nbsp;pBlockTable-&gt;close();</p><p>&nbsp;&nbsp;pText = NULL;<br/>&nbsp;}</p><p>&nbsp;&nbsp;&nbsp; pTextStyleTable-&gt;close();<br/>&nbsp;return objId;<br/>}<br/></p><p>下面贴一个别人写的数据转换的例子:</p><p>作者:程佩君 <br/>刚接触VC编程的朋友往往对许多数据类型的转换感到迷惑不解,本文将介绍一些常用数据类型的使用。 </p><p>我们先定义一些常见类型变量借以说明 </p><p>int i = 100; <br/>long l = 2001; <br/>float f=300.2; <br/>double d=12345.119; <br/>char username[]="女侠程佩君"; <br/>char temp; <br/>char *buf; <br/>CString str; <br/>_variant_t v1; <br/>_bstr_t v2; </p><p>一、其它数据类型转换为字符串 </p><p>短整型(int) <br/>itoa(i,temp,10);///将i转换为字符串放入temp中,最后一个数字表示十进制 <br/>itoa(i,temp,2); ///按二进制方式转换 <br/>长整型(long) <br/>ltoa(l,temp,10); </p><p>二、从其它包含字符串的变量中获取指向该字符串的指针 </p><p>CString变量 <br/>str = "2008北京奥运"; <br/>buf = (LPSTR)(LPCTSTR)str; <br/>BSTR类型的_variant_t变量 <br/>v1 = (_bstr_t)"程序员"; <br/>buf = _com_util::ConvertBSTRToString((_bstr_t)v1); </p><p>三、字符串转换为其它数据类型 <br/>strcpy(temp,"123"); </p><p>短整型(int) <br/>i = atoi(temp); <br/>长整型(long) <br/>l = atol(temp); <br/>浮点(double) <br/>d = atof(temp); </p><p>四、其它数据类型转换到CString <br/>使用CString的成员函数Format来转换,例如: </p><p>整数(int) <br/>str.Format("%d",i); <br/>浮点数(float) <br/>str.Format("%f",i); <br/>字符串指针(char *)等已经被CString构造函数支持的数据类型可以直接赋值 <br/>str = username; </p><p>五、BSTR、_bstr_t与CComBSTR </p><p>CComBSTR、_bstr_t是对BSTR的封装,BSTR是指向字符串的32位指针。 <br/>char *转换到BSTR可以这样: BSTR b=_com_util::ConvertStringToBSTR("数据");///使用前需要加上头文件comutil.h <br/>反之可以使用char *p=_com_util::ConvertBSTRToString(b); </p><p>六、VARIANT 、_variant_t 与 COleVariant </p><p>VARIANT的结构可以参考头文件VC98\Include\OAIDL.H中关于结构体tagVARIANT的定义。 <br/>对于VARIANT变量的赋值:首先给vt成员赋值,指明数据类型,再对联合结构中相同数据类型的变量赋值,举个例子: <br/>VARIANT va; <br/>int a=2001; <br/>va.vt=VT_I4;///指明整型数据 <br/>va.lVal=a; ///赋值 </p><p>对于不马上赋值的VARIANT,最好先用Void VariantInit(VARIANTARG FAR* pvarg);进行初始化,其本质是将vt设置为VT_EMPTY,下表我们列举vt与常用数据的对应关系: </p><p>unsigned char bVal; VT_UI1 <br/>short iVal; VT_I2 <br/>long lVal; VT_I4 <br/>float fltVal; VT_R4 <br/>double dblVal; VT_R8 <br/>VARIANT_BOOL boolVal; VT_BOOL <br/>SCODE scode; VT_ERROR <br/>CY cyVal; VT_CY <br/>DATE date; VT_DATE <br/>BSTR bstrVal; VT_BSTR <br/>IUnknown FAR* punkVal; VT_UNKNOWN <br/>IDispatch FAR* pdispVal; VT_DISPATCH <br/>SAFEARRAY FAR* parray; VT_ARRAY|* <br/>unsigned char FAR* pbVal; VT_BYREF|VT_UI1 <br/>short FAR* piVal; VT_BYREF|VT_I2 <br/>long FAR* plVal; VT_BYREF|VT_I4 <br/>float FAR* pfltVal; VT_BYREF|VT_R4 <br/>double FAR* pdblVal; VT_BYREF|VT_R8 <br/>VARIANT_BOOL FAR* pboolVal; VT_BYREF|VT_BOOL <br/>SCODE FAR* pscode; VT_BYREF|VT_ERROR <br/>CY FAR* pcyVal; VT_BYREF|VT_CY <br/>DATE FAR* pdate; VT_BYREF|VT_DATE <br/>BSTR FAR* pbstrVal; VT_BYREF|VT_BSTR <br/>IUnknown FAR* FAR* ppunkVal; VT_BYREF|VT_UNKNOWN <br/>IDispatch FAR* FAR* ppdispVal; VT_BYREF|VT_DISPATCH <br/>SAFEARRAY FAR* FAR* pparray; VT_ARRAY|* <br/>VARIANT FAR* pvarVal; VT_BYREF|VT_VARIANT <br/>void FAR* byref; VT_BYREF </p><p>_variant_t是VARIANT的封装类,其赋值可以使用强制类型转换,其构造函数会自动处理这些数据类型。 <br/>例如: <br/>long l=222; <br/>ing i=100; <br/>_variant_t lVal(l); <br/>lVal = (long)i; </p><p>COleVariant的使用与_variant_t的方法基本一样,请参考如下例子: <br/>COleVariant v3 = "字符串", v4 = (long)1999; <br/>CString str =(BSTR)v3.pbstrVal; <br/>long i = v4.lVal; </p><p>七、其它 </p><p>对消息的处理中我们经常需要将WPARAM或LPARAM等32位数据(DWORD)分解成两个16位数据(WORD),例如: <br/>LPARAM lParam; <br/>WORD loValue = LOWORD(lParam);///取低16位 <br/>WORD hiValue = HIWORD(lParam);///取高16位 <br/>对于16位的数据(WORD)我们可以用同样的方法分解成高低两个8位数据(BYTE),例如: <br/>WORD wValue; <br/>BYTE loValue = LOBYTE(wValue);///取低8位 <br/>BYTE hiValue = HIBYTE(wValue);///取高8位 <br/>后记:本文匆匆写成,错误之处在所难免,欢迎来信指正. </p>

zhang007 发表于 2007-8-16 08:58:00

<p>这个问题涉及到变量的转换,各种类型变量转换成字符串方法不一样,转换成字符串后再添加数据库中,下面是添加文字的函数,如果你看不懂的话,多看多做ARX中SAMPLE下面的例子,多试几次..</p><p>AcDbObjectId&nbsp; createText(AcGePoint3d pt,CString strText,<br/>&nbsp;&nbsp;&nbsp;&nbsp;char *pStyleName,double Height,double dWidth,<br/>&nbsp;&nbsp;&nbsp;&nbsp;double rotation,char *pLayerName,AcDb::TextVertMode vMode,<br/>&nbsp;&nbsp;&nbsp;&nbsp;AcDb::TextHorzMode hMode)<br/>{<br/>&nbsp;AcDbTextStyleTable *pTextStyleTable;<br/>&nbsp;AcDbObjectId objId,styleId;<br/>&nbsp;char text;</p><p>&nbsp;&nbsp;&nbsp; acdbHostApplicationServices()-&gt;workingDatabase()<br/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; -&gt;getSymbolTable(pTextStyleTable, AcDb::kForRead);</p><p>&nbsp;if (!pTextStyleTable-&gt;has(pStyleName)){<br/>&nbsp;&nbsp;pTextStyleTable-&gt;close();<br/>&nbsp;&nbsp;createTextStyle(pStyleName,"romanc.shx","hzdx.shx",Height,1.0,0.0,1.0);<br/>&nbsp;&nbsp;&nbsp;&nbsp; acdbHostApplicationServices()-&gt;workingDatabase()<br/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; -&gt;getSymbolTable(pTextStyleTable, AcDb::kForRead);<br/>&nbsp;}<br/>&nbsp;if (pTextStyleTable-&gt;has(pStyleName)){<br/>&nbsp;&nbsp;pTextStyleTable-&gt;getAt(pStyleName,styleId,Adesk::kFalse);<br/>&nbsp;&nbsp;//′′?¨??×?<br/>&nbsp;&nbsp;AcDbBlockTable *pBlockTable;<br/>&nbsp;&nbsp;acdbHostApplicationServices()-&gt;workingDatabase()<br/>&nbsp;&nbsp;&nbsp;-&gt;getSymbolTable(pBlockTable,AcDb::kForRead);<br/>&nbsp;&nbsp;AcDbBlockTableRecord *pSpace;<br/>&nbsp;&nbsp;pBlockTable-&gt;getAt(ACDB_MODEL_SPACE,pSpace,AcDb::kForWrite);<br/>&nbsp;&nbsp;pBlockTable-&gt;close();</p><p>&nbsp;&nbsp;&nbsp; &nbsp;strcpy(text,strText);<br/>&nbsp;&nbsp;AcDbText *pText = new<br/>&nbsp;&nbsp;&nbsp;AcDbText(pt,text,styleId,Height,rotation);<br/>&nbsp;&nbsp;if(dWidth != 1.0)pText-&gt;setWidthFactor(dWidth);<br/>&nbsp;&nbsp;pText-&gt;setLayer(pLayerName);<br/>&nbsp;&nbsp;pText-&gt;setVerticalMode(vMode);<br/>&nbsp;&nbsp;pText-&gt;setHorizontalMode(hMode);<br/>&nbsp;&nbsp;pText-&gt;setAlignmentPoint(pt);<br/>&nbsp;&nbsp;pSpace-&gt;appendAcDbEntity(objId,pText);<br/>&nbsp;&nbsp;pText-&gt;close();<br/>&nbsp;&nbsp;pSpace-&gt;close();<br/>&nbsp;&nbsp;pBlockTable-&gt;close();</p><p>&nbsp;&nbsp;pText = NULL;<br/>&nbsp;}</p><p>&nbsp;&nbsp;&nbsp; pTextStyleTable-&gt;close();<br/>&nbsp;return objId;<br/>}<br/></p><p>下面贴一个别人写的数据转换的例子:</p><p>作者:程佩君 <br/>刚接触VC编程的朋友往往对许多数据类型的转换感到迷惑不解,本文将介绍一些常用数据类型的使用。 </p><p>我们先定义一些常见类型变量借以说明 </p><p>int i = 100; <br/>long l = 2001; <br/>float f=300.2; <br/>double d=12345.119; <br/>char username[]="女侠程佩君"; <br/>char temp; <br/>char *buf; <br/>CString str; <br/>_variant_t v1; <br/>_bstr_t v2; </p><p>一、其它数据类型转换为字符串 </p><p>短整型(int) <br/>itoa(i,temp,10);///将i转换为字符串放入temp中,最后一个数字表示十进制 <br/>itoa(i,temp,2); ///按二进制方式转换 <br/>长整型(long) <br/>ltoa(l,temp,10); </p><p>二、从其它包含字符串的变量中获取指向该字符串的指针 </p><p>CString变量 <br/>str = "2008北京奥运"; <br/>buf = (LPSTR)(LPCTSTR)str; <br/>BSTR类型的_variant_t变量 <br/>v1 = (_bstr_t)"程序员"; <br/>buf = _com_util::ConvertBSTRToString((_bstr_t)v1); </p><p>三、字符串转换为其它数据类型 <br/>strcpy(temp,"123"); </p><p>短整型(int) <br/>i = atoi(temp); <br/>长整型(long) <br/>l = atol(temp); <br/>浮点(double) <br/>d = atof(temp); </p><p>四、其它数据类型转换到CString <br/>使用CString的成员函数Format来转换,例如: </p><p>整数(int) <br/>str.Format("%d",i); <br/>浮点数(float) <br/>str.Format("%f",i); <br/>字符串指针(char *)等已经被CString构造函数支持的数据类型可以直接赋值 <br/>str = username; </p><p>五、BSTR、_bstr_t与CComBSTR </p><p>CComBSTR、_bstr_t是对BSTR的封装,BSTR是指向字符串的32位指针。 <br/>char *转换到BSTR可以这样: BSTR b=_com_util::ConvertStringToBSTR("数据");///使用前需要加上头文件comutil.h <br/>反之可以使用char *p=_com_util::ConvertBSTRToString(b); </p><p>六、VARIANT 、_variant_t 与 COleVariant </p><p>VARIANT的结构可以参考头文件VC98\Include\OAIDL.H中关于结构体tagVARIANT的定义。 <br/>对于VARIANT变量的赋值:首先给vt成员赋值,指明数据类型,再对联合结构中相同数据类型的变量赋值,举个例子: <br/>VARIANT va; <br/>int a=2001; <br/>va.vt=VT_I4;///指明整型数据 <br/>va.lVal=a; ///赋值 </p><p>对于不马上赋值的VARIANT,最好先用Void VariantInit(VARIANTARG FAR* pvarg);进行初始化,其本质是将vt设置为VT_EMPTY,下表我们列举vt与常用数据的对应关系: </p><p>unsigned char bVal; VT_UI1 <br/>short iVal; VT_I2 <br/>long lVal; VT_I4 <br/>float fltVal; VT_R4 <br/>double dblVal; VT_R8 <br/>VARIANT_BOOL boolVal; VT_BOOL <br/>SCODE scode; VT_ERROR <br/>CY cyVal; VT_CY <br/>DATE date; VT_DATE <br/>BSTR bstrVal; VT_BSTR <br/>IUnknown FAR* punkVal; VT_UNKNOWN <br/>IDispatch FAR* pdispVal; VT_DISPATCH <br/>SAFEARRAY FAR* parray; VT_ARRAY|* <br/>unsigned char FAR* pbVal; VT_BYREF|VT_UI1 <br/>short FAR* piVal; VT_BYREF|VT_I2 <br/>long FAR* plVal; VT_BYREF|VT_I4 <br/>float FAR* pfltVal; VT_BYREF|VT_R4 <br/>double FAR* pdblVal; VT_BYREF|VT_R8 <br/>VARIANT_BOOL FAR* pboolVal; VT_BYREF|VT_BOOL <br/>SCODE FAR* pscode; VT_BYREF|VT_ERROR <br/>CY FAR* pcyVal; VT_BYREF|VT_CY <br/>DATE FAR* pdate; VT_BYREF|VT_DATE <br/>BSTR FAR* pbstrVal; VT_BYREF|VT_BSTR <br/>IUnknown FAR* FAR* ppunkVal; VT_BYREF|VT_UNKNOWN <br/>IDispatch FAR* FAR* ppdispVal; VT_BYREF|VT_DISPATCH <br/>SAFEARRAY FAR* FAR* pparray; VT_ARRAY|* <br/>VARIANT FAR* pvarVal; VT_BYREF|VT_VARIANT <br/>void FAR* byref; VT_BYREF </p><p>_variant_t是VARIANT的封装类,其赋值可以使用强制类型转换,其构造函数会自动处理这些数据类型。 <br/>例如: <br/>long l=222; <br/>ing i=100; <br/>_variant_t lVal(l); <br/>lVal = (long)i; </p><p>COleVariant的使用与_variant_t的方法基本一样,请参考如下例子: <br/>COleVariant v3 = "字符串", v4 = (long)1999; <br/>CString str =(BSTR)v3.pbstrVal; <br/>long i = v4.lVal; </p><p>七、其它 </p><p>对消息的处理中我们经常需要将WPARAM或LPARAM等32位数据(DWORD)分解成两个16位数据(WORD),例如: <br/>LPARAM lParam; <br/>WORD loValue = LOWORD(lParam);///取低16位 <br/>WORD hiValue = HIWORD(lParam);///取高16位 <br/>对于16位的数据(WORD)我们可以用同样的方法分解成高低两个8位数据(BYTE),例如: <br/>WORD wValue; <br/>BYTE loValue = LOBYTE(wValue);///取低8位 <br/>BYTE hiValue = HIBYTE(wValue);///取高8位 <br/>后记:本文匆匆写成,错误之处在所难免,欢迎来信指正. </p>

zhang007 发表于 2007-8-16 08:58:00

<p>这个问题涉及到变量的转换,各种类型变量转换成字符串方法不一样,转换成字符串后再添加数据库中,下面是添加文字的函数,如果你看不懂的话,多看多做ARX中SAMPLE下面的例子,多试几次..</p><p>AcDbObjectId&nbsp; createText(AcGePoint3d pt,CString strText,<br/>&nbsp;&nbsp;&nbsp;&nbsp;char *pStyleName,double Height,double dWidth,<br/>&nbsp;&nbsp;&nbsp;&nbsp;double rotation,char *pLayerName,AcDb::TextVertMode vMode,<br/>&nbsp;&nbsp;&nbsp;&nbsp;AcDb::TextHorzMode hMode)<br/>{<br/>&nbsp;AcDbTextStyleTable *pTextStyleTable;<br/>&nbsp;AcDbObjectId objId,styleId;<br/>&nbsp;char text;</p><p>&nbsp;&nbsp;&nbsp; acdbHostApplicationServices()-&gt;workingDatabase()<br/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; -&gt;getSymbolTable(pTextStyleTable, AcDb::kForRead);</p><p>&nbsp;if (!pTextStyleTable-&gt;has(pStyleName)){<br/>&nbsp;&nbsp;pTextStyleTable-&gt;close();<br/>&nbsp;&nbsp;createTextStyle(pStyleName,"romanc.shx","hzdx.shx",Height,1.0,0.0,1.0);<br/>&nbsp;&nbsp;&nbsp;&nbsp; acdbHostApplicationServices()-&gt;workingDatabase()<br/>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; -&gt;getSymbolTable(pTextStyleTable, AcDb::kForRead);<br/>&nbsp;}<br/>&nbsp;if (pTextStyleTable-&gt;has(pStyleName)){<br/>&nbsp;&nbsp;pTextStyleTable-&gt;getAt(pStyleName,styleId,Adesk::kFalse);<br/>&nbsp;&nbsp;//′′?¨??×?<br/>&nbsp;&nbsp;AcDbBlockTable *pBlockTable;<br/>&nbsp;&nbsp;acdbHostApplicationServices()-&gt;workingDatabase()<br/>&nbsp;&nbsp;&nbsp;-&gt;getSymbolTable(pBlockTable,AcDb::kForRead);<br/>&nbsp;&nbsp;AcDbBlockTableRecord *pSpace;<br/>&nbsp;&nbsp;pBlockTable-&gt;getAt(ACDB_MODEL_SPACE,pSpace,AcDb::kForWrite);<br/>&nbsp;&nbsp;pBlockTable-&gt;close();</p><p>&nbsp;&nbsp;&nbsp; &nbsp;strcpy(text,strText);<br/>&nbsp;&nbsp;AcDbText *pText = new<br/>&nbsp;&nbsp;&nbsp;AcDbText(pt,text,styleId,Height,rotation);<br/>&nbsp;&nbsp;if(dWidth != 1.0)pText-&gt;setWidthFactor(dWidth);<br/>&nbsp;&nbsp;pText-&gt;setLayer(pLayerName);<br/>&nbsp;&nbsp;pText-&gt;setVerticalMode(vMode);<br/>&nbsp;&nbsp;pText-&gt;setHorizontalMode(hMode);<br/>&nbsp;&nbsp;pText-&gt;setAlignmentPoint(pt);<br/>&nbsp;&nbsp;pSpace-&gt;appendAcDbEntity(objId,pText);<br/>&nbsp;&nbsp;pText-&gt;close();<br/>&nbsp;&nbsp;pSpace-&gt;close();<br/>&nbsp;&nbsp;pBlockTable-&gt;close();</p><p>&nbsp;&nbsp;pText = NULL;<br/>&nbsp;}</p><p>&nbsp;&nbsp;&nbsp; pTextStyleTable-&gt;close();<br/>&nbsp;return objId;<br/>}<br/></p><p>下面贴一个别人写的数据转换的例子:</p><p>作者:程佩君 <br/>刚接触VC编程的朋友往往对许多数据类型的转换感到迷惑不解,本文将介绍一些常用数据类型的使用。 </p><p>我们先定义一些常见类型变量借以说明 </p><p>int i = 100; <br/>long l = 2001; <br/>float f=300.2; <br/>double d=12345.119; <br/>char username[]="女侠程佩君"; <br/>char temp; <br/>char *buf; <br/>CString str; <br/>_variant_t v1; <br/>_bstr_t v2; </p><p>一、其它数据类型转换为字符串 </p><p>短整型(int) <br/>itoa(i,temp,10);///将i转换为字符串放入temp中,最后一个数字表示十进制 <br/>itoa(i,temp,2); ///按二进制方式转换 <br/>长整型(long) <br/>ltoa(l,temp,10); </p><p>二、从其它包含字符串的变量中获取指向该字符串的指针 </p><p>CString变量 <br/>str = "2008北京奥运"; <br/>buf = (LPSTR)(LPCTSTR)str; <br/>BSTR类型的_variant_t变量 <br/>v1 = (_bstr_t)"程序员"; <br/>buf = _com_util::ConvertBSTRToString((_bstr_t)v1); </p><p>三、字符串转换为其它数据类型 <br/>strcpy(temp,"123"); </p><p>短整型(int) <br/>i = atoi(temp); <br/>长整型(long) <br/>l = atol(temp); <br/>浮点(double) <br/>d = atof(temp); </p><p>四、其它数据类型转换到CString <br/>使用CString的成员函数Format来转换,例如: </p><p>整数(int) <br/>str.Format("%d",i); <br/>浮点数(float) <br/>str.Format("%f",i); <br/>字符串指针(char *)等已经被CString构造函数支持的数据类型可以直接赋值 <br/>str = username; </p><p>五、BSTR、_bstr_t与CComBSTR </p><p>CComBSTR、_bstr_t是对BSTR的封装,BSTR是指向字符串的32位指针。 <br/>char *转换到BSTR可以这样: BSTR b=_com_util::ConvertStringToBSTR("数据");///使用前需要加上头文件comutil.h <br/>反之可以使用char *p=_com_util::ConvertBSTRToString(b); </p><p>六、VARIANT 、_variant_t 与 COleVariant </p><p>VARIANT的结构可以参考头文件VC98\Include\OAIDL.H中关于结构体tagVARIANT的定义。 <br/>对于VARIANT变量的赋值:首先给vt成员赋值,指明数据类型,再对联合结构中相同数据类型的变量赋值,举个例子: <br/>VARIANT va; <br/>int a=2001; <br/>va.vt=VT_I4;///指明整型数据 <br/>va.lVal=a; ///赋值 </p><p>对于不马上赋值的VARIANT,最好先用Void VariantInit(VARIANTARG FAR* pvarg);进行初始化,其本质是将vt设置为VT_EMPTY,下表我们列举vt与常用数据的对应关系: </p><p>unsigned char bVal; VT_UI1 <br/>short iVal; VT_I2 <br/>long lVal; VT_I4 <br/>float fltVal; VT_R4 <br/>double dblVal; VT_R8 <br/>VARIANT_BOOL boolVal; VT_BOOL <br/>SCODE scode; VT_ERROR <br/>CY cyVal; VT_CY <br/>DATE date; VT_DATE <br/>BSTR bstrVal; VT_BSTR <br/>IUnknown FAR* punkVal; VT_UNKNOWN <br/>IDispatch FAR* pdispVal; VT_DISPATCH <br/>SAFEARRAY FAR* parray; VT_ARRAY|* <br/>unsigned char FAR* pbVal; VT_BYREF|VT_UI1 <br/>short FAR* piVal; VT_BYREF|VT_I2 <br/>long FAR* plVal; VT_BYREF|VT_I4 <br/>float FAR* pfltVal; VT_BYREF|VT_R4 <br/>double FAR* pdblVal; VT_BYREF|VT_R8 <br/>VARIANT_BOOL FAR* pboolVal; VT_BYREF|VT_BOOL <br/>SCODE FAR* pscode; VT_BYREF|VT_ERROR <br/>CY FAR* pcyVal; VT_BYREF|VT_CY <br/>DATE FAR* pdate; VT_BYREF|VT_DATE <br/>BSTR FAR* pbstrVal; VT_BYREF|VT_BSTR <br/>IUnknown FAR* FAR* ppunkVal; VT_BYREF|VT_UNKNOWN <br/>IDispatch FAR* FAR* ppdispVal; VT_BYREF|VT_DISPATCH <br/>SAFEARRAY FAR* FAR* pparray; VT_ARRAY|* <br/>VARIANT FAR* pvarVal; VT_BYREF|VT_VARIANT <br/>void FAR* byref; VT_BYREF </p><p>_variant_t是VARIANT的封装类,其赋值可以使用强制类型转换,其构造函数会自动处理这些数据类型。 <br/>例如: <br/>long l=222; <br/>ing i=100; <br/>_variant_t lVal(l); <br/>lVal = (long)i; </p><p>COleVariant的使用与_variant_t的方法基本一样,请参考如下例子: <br/>COleVariant v3 = "字符串", v4 = (long)1999; <br/>CString str =(BSTR)v3.pbstrVal; <br/>long i = v4.lVal; </p><p>七、其它 </p><p>对消息的处理中我们经常需要将WPARAM或LPARAM等32位数据(DWORD)分解成两个16位数据(WORD),例如: <br/>LPARAM lParam; <br/>WORD loValue = LOWORD(lParam);///取低16位 <br/>WORD hiValue = HIWORD(lParam);///取高16位 <br/>对于16位的数据(WORD)我们可以用同样的方法分解成高低两个8位数据(BYTE),例如: <br/>WORD wValue; <br/>BYTE loValue = LOBYTE(wValue);///取低8位 <br/>BYTE hiValue = HIBYTE(wValue);///取高8位 <br/>后记:本文匆匆写成,错误之处在所难免,欢迎来信指正. </p>
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