用VC调整显示器的分辨率 zz

 

调整分辨率的代码如下：
DEVMODE dm;
 dm.dmSize = sizeof(DEVMODE) ;
 EnumDisplaySettings(NULL,ENUM_CURRENT_SETTINGS,&dm);
 if(dm.dmPelsHeight!=1024||dm.dmPelsWidth!=1280){
  if(AfxMessageBox("为了达到最好的显示效果，建议您使用1280*1024的分辨率，确定吗？",MB_YESNO)==IDYES){
   LONG result;
   dm.dmBitsPerPel = 32;
   dm.dmPelsHeight = 1024;
   dm.dmPelsWidth = 1280;
   dm.dmFields = DM_BITSPERPEL|DM_PELSWIDTH|DM_PELSHEIGHT;
   result = ChangeDisplaySettings(&dm,0);
  }
 }
“如果要在程序启动时自动自动调整到合适的分辨率，可以将其加入到View的OnInitialUpdate()中，并记录下dm.dmPelsHeight和dm.dmPelsWidth的值。
要在程序结束时自动调整回原有分辨率，可在MainFrame的OnClose()中用以上代码将其改回原值。”

如果要在程序启动时自动自动调整到合适的分辨率，可以将其加入到app的InitInstance()中，并记录下dm.dmPelsHeight和dm.dmPelsWidth的值。
要在程序结束时自动调整回原有分辨率，可在APP的ExitInstance中用以上代码将其改回原值。”

posted @ 2009-03-24 11:19 Alina-zl 阅读(512) | 评论 (0) | 编辑 收藏

vc2005中没有classwizard这个命令了 2005下怎么添加鼠标事件

vc2005中没有classwizard这个命令了

取代classwizard 中的添加消息映射，添加类，等等的功能主要在属性窗口中

鼠标事件不要手动添加，最好使用下述方法

比如添加消息映射。你选定了一个类后，在属性点击右键 选择属性
在属性窗口中点击那个像闪电样的 图标 就会出现 一系列的消息供你选择 ，点击 小方快样子的图标 就会出现虚函数或者重载

至于添加类，直接在工程名称上点右键 选择 添加类的命令 即可

添加变量 ，可以在类名称上点右键，选择添加变量

posted @ 2008-12-30 11:51 Alina-zl 阅读(870) | 评论 (0) | 编辑 收藏

'IDD_DIALOG1' : undeclared identifier

error   C2065:   'IDD_DIALOG1'   :   undeclared   identifier  

解决办法:

加#include   'resource.h'

posted @ 2008-12-16 19:20 Alina-zl 阅读(1971) | 评论 (1) | 编辑 收藏

MFC与namespace的冲突问题

把代码从QT移植到MFC的时候，这个文件vecmat.h，出现了如下错误：
error C2143: syntax error : missing ',' before ')'
error C2143: syntax error : missing ';' before '}'
error C2059: syntax error : ')'
fatal error C1004: unexpected end-of-file found
等等。
vecmat.h源代码如下:

#ifndef  VECMAT_H
# define VECMAT_H

# include <cmath>
# include <vector>
# include <iostream>

 

namespace vecmat {

 namespace internal {

  template <bool B>
  struct is_false {};

  template <>
  struct is_false<false> {
   static inline void ensure() {}
  };

 } // end of namespace internal

 //
 //  Vector class
 //    - T: value type
 //    - N: dimension
 //
 /////////////////////////////////////////////////////////////////////////////

 template <class T, unsigned N>
 class Vector
 {
 public:

  typedef T value_type;

  // constructors

  inline Vector() {
   for (unsigned i = 0; i < N; i++)
    _coord[i] = 0;
  }

  ~Vector() {
   internal::is_false<(N == 0)>::ensure();
  }

  template <class U>
  explicit inline Vector(const U tab[N]) {
   for (unsigned i = 0; i < N; i++)
    _coord[i] = (T)tab[i];
  }

  template <class U>
  explicit inline Vector(const std::vector<U>& tab) {
   for (unsigned i = 0; i < N; i++)
    _coord[i] = (T)tab[i];
  }

  template <class U>
  explicit inline Vector(const Vector<U, N>& v) {
   for (unsigned i = 0; i < N; i++)
    _coord[i] = (T)v[i];
  }

  // accessors

  inline value_type  operator[](const unsigned i) const {
   return _coord[i];
  }

  inline value_type& operator[](const unsigned i) {
   return _coord[i];
  }

  static inline unsigned dim() {
   return N;
  }

  // various useful methods

  inline value_type norm() const {
   return (T)sqrt(squareNorm());
  }

  inline value_type squareNorm() const {
   return (*this) * (*this);
  }

  inline Vector<T, N>& normalize() {
   value_type n = norm();
   for (unsigned i = 0; i < N; i++)
    _coord[i] /= n;
   return *this;
  }

  inline Vector<T, N>& normalizeSafe() {
   value_type n = norm();
   if (n)
    for (unsigned i=0; i < N; i++)
     _coord[i] /= n;
   return *this;
  }

  inline Vector<T, N>& min(const Vector<T, N>& v) {
   for (unsigned i=0; i < N; i++)
    if (_coord[i]  > v._coord[i])
     _coord[i] = v._coord[i];
   return *this;
  }

  inline Vector<T, N>& max(const Vector<T, N>& v) {
   for (unsigned i=0; i < N; i++)
    if (_coord[i]  < v._coord[i])
     _coord[i] = v._coord[i];
   return *this;
  }

  inline const value_type* address() const {
   return _coord;
  }

  // classical operators

  template <class U>
  inline Vector<T, N>& operator=(const Vector<U, N>& v) {
   if (this != &v)
    for (unsigned i = 0; i < N; i++)
     _coord[i] = (T)v[i];
   return *this;
  }

  template <class U>
  inline Vector<T, N>& operator+=(const Vector<U, N>& v) {
   for (unsigned i = 0 ; i < N; i++)
    _coord[i] += (T)v[i];
   return *this;
  }

  template <class U>
  inline Vector<T, N>& operator-=(const Vector<U, N>& v) {
   for (unsigned i = 0 ; i < N; i++)
    _coord[i] -= (T)v[i];
   return *this;
  }

  template <class U>
  inline Vector<T, N>& operator*=(const U r) {
   for (unsigned i = 0 ; i < N; i++)
    _coord[i] *= r;
   return *this;
  }

  template <class U>
  inline Vector<T, N>& operator/=(const U r) {
   if (r)
    for (unsigned i = 0 ; i < N; i++)
     _coord[i] /= r;
   return *this;
  }

  inline bool operator==(const Vector<T, N>& v) const {
   for(unsigned i = 0; i < N; i++)
    if (_coord[i] != v[i])
     return false;
   return true;
  }

  inline bool operator!=(const Vector<T, N>& v) const {
   for(unsigned i = 0; i < N; i++)
    if (_coord[i] != v[i])
     return true;
   return false;
  }

  inline bool operator<(const Vector<T, N>& v) const {
   for (unsigned i = 0; i<N; i++) {
    if (_coord[i] < v[i])
     return true;
    if (_coord[i] > v[i])
     return false;
    if (_coord[i] == v[i])
     continue;
   }
   return false; 
  }

  inline bool operator>(const Vector<T, N>& v) const {
   for (unsigned i=0; i<N; i++) {
    if(_coord[i] > v[i])
     return true;
    if(_coord[i] < v[i])
     return false;
    if(_coord[i] == v[i])
     continue;
   }
   return false; 
  }

 protected:

  value_type _coord[N];
  enum {
   _dim = N,
  };
 };

 //
 //  Vec2 class (2D Vector)
 //    - T: value type
 //
 /////////////////////////////////////////////////////////////////////////////

 template <class T>
 class Vec2 : public Vector<T, 2>
 {
 public:

  typedef typename Vector<T, 2>::value_type value_type;

  inline Vec2() : Vector<T, 2>() {}

  template <class U>
  explicit inline Vec2(const U tab[2]) : Vector<T, 2>(tab) {}

  template <class U>
  explicit inline Vec2(const std::vector<U>& tab) : Vector<T, 2>(tab) {}

  template <class U>
  inline Vec2(const Vector<U, 2>& v) : Vector<T, 2>(v) {}

  inline Vec2(const value_type x,
   const value_type y = 0) : Vector<T, 2>() {
    this->_coord[0] = (T)x;
    this->_coord[1] = (T)y;
  }

  inline value_type x() const {
   return this->_coord[0];
  }

  inline value_type& x() {
   return this->_coord[0];
  }

  inline value_type y() const {
   return this->_coord[1];
  }

  inline value_type& y() {
   return this->_coord[1];
  }
 };

 //
 //  HVec3 class (3D Vector in homogeneous coordinates)
 //    - T: value type
 //
 /////////////////////////////////////////////////////////////////////////////

 template <class T>
 class HVec3 : public Vector<T, 4>
 {
 public:

  typedef typename Vector<T, 4>::value_type value_type;

  inline HVec3() : Vector<T, 4>() {}

  template <class U>
  explicit inline HVec3(const U tab[4]) : Vector<T, 4>(tab) {}

  template <class U>
  explicit inline HVec3(const std::vector<U>& tab) : Vector<T, 4>(tab) {}

  template<class U>
  inline HVec3(const Vector<U, 4>& v) : Vector<T, 4>(v) {}

  inline HVec3(const value_type sx,
   const value_type sy = 0,
   const value_type sz = 0,
   const value_type s = 1) {
    this->_coord[0] = sx;
    this->_coord[1] = sy;
    this->_coord[2] = sz;
    this->_coord[3] = s;
  }

  template <class U>
  inline HVec3(const Vector<U, 3>& sv) {
   this->_coord[0] = (T)sv[0];
   this->_coord[1] = (T)sv[1];
   this->_coord[2] = (T)sv[2];
   this->_coord[3] = (T)1;
  }

  template <class U>
  inline HVec3(const Vector<U, 3>& sv,
   const U) {
    this->_coord[0] = (T)sv[0];
    this->_coord[1] = (T)sv[1];
    this->_coord[2] = (T)sv[2];
    this->_coord[3] = (T)s;
  }

  inline value_type sx() const {
   return this->_coord[0];
  }

  inline value_type& sx() {
   return this->_coord[0];
  }

  inline value_type sy() const {
   return this->_coord[1];
  }

  inline value_type& sy() {
   return this->_coord[1];
  }

  inline value_type sz() const {
   return this->_coord[2];
  }

  inline value_type& sz() {
   return this->_coord[2];
  }

  inline value_type s() const {
   return this->_coord[3];
  }

  inline value_type& s() {
   return this->_coord[3];
  }

  // Acces to non-homogeneous coordinates in 3D

  inline value_type x() const {
   return this->_coord[0] / this->_coord[3];
  }

  inline value_type y() const {
   return this->_coord[1] / this->_coord[3];
  }

  inline value_type z() const {
   return this->_coord[2] / this->_coord[3];
  }
 };

 //
 //  Vec3 class (3D Vector)
 //    - T: value type
 //
 /////////////////////////////////////////////////////////////////////////////

 template <class T>
 class Vec3 : public Vector<T, 3>
 {
 public:

  typedef typename Vector<T, 3>::value_type value_type;

  inline Vec3() : Vector<T, 3>() {}

  template <class U>
  explicit inline Vec3(const U tab[3]) : Vector<T, 3>(tab) {}

  template <class U>
  explicit inline Vec3(const std::vector<U>& tab) : Vector<T, 3>(tab) {}

  template<class U>
  inline Vec3(const Vector<U, 3>& v) : Vector<T, 3>(v) {}

  template<class U>
  inline Vec3(const HVec3<U>& v) {
   this->_coord[0] = (T)v.x();
   this->_coord[1] = (T)v.y();
   this->_coord[2] = (T)v.z();
  }

  inline Vec3(const value_type x,
   const value_type y = 0,
   const value_type z = 0) : Vector<T, 3>() {
    this->_coord[0] = x;
    this->_coord[1] = y;
    this->_coord[2] = z;
  }

  inline value_type x() const {
   return this->_coord[0];
  }

  inline value_type& x() {
   return this->_coord[0];
  }

  inline value_type y() const {
   return this->_coord[1];
  }

  inline value_type& y() {
   return this->_coord[1];
  }

  inline value_type z() const {
   return this->_coord[2];
  }

  inline value_type& z() {
   return this->_coord[2];
  }
 };

 //
 //  Matrix class
 //    - T: value type
 //    - M: rows
 //    - N: cols
 //
 /////////////////////////////////////////////////////////////////////////////

 // Dirty, but icc under Windows needs this
# define _SIZE (M * N)

 template <class T, unsigned M, unsigned N>
 class Matrix
 {
 public:

  typedef T value_type;

  inline Matrix() {
   for (unsigned i = 0; i < _SIZE; i++)
    this->_coord[i] = 0;
  }

  ~Matrix() {
   internal::is_false<(M == 0)>::ensure();
   internal::is_false<(N == 0)>::ensure();
  }

  template <class U>
  explicit inline Matrix(const U tab[M][N]) {
   for (unsigned i = 0; i < M; i++)
    for (unsigned j = 0; j < N; j++)
     this->_coord[i * N + j] = tab[i][j];
  }

  template <class U>
  explicit inline Matrix(const U tab[_SIZE]) {
   for (unsigned i = 0; i < _SIZE; i++)
    this->_coord[i] = tab[i];
  }

  template <class U>
  explicit inline Matrix(const std::vector<U>& tab) {
   for (unsigned i = 0; i < _SIZE; i++)
    this->_coord[i] = tab[i];
  }

  template <class U>
  inline Matrix(const Matrix<U, M, N>& m) {
   for (unsigned i = 0; i < M; i++)
    for (unsigned j = 0; j < N; j++)
     this->_coord[i * N + j] = (T)m(i, j);
  }

  inline value_type operator()(const unsigned i, const unsigned j) const {
   return this->_coord[i * N + j];
  }

  inline value_type& operator()(const unsigned i, const unsigned j) {
   return this->_coord[i * N + j];
  }

  static inline unsigned rows() {
   return M;
  }

  static inline unsigned cols() {
   return N;
  }

  inline Matrix<T, M, N> transpose() const {
   Matrix<T, N, M> res;
   for (unsigned i = 0; i < M; i++)
    for (unsigned j = 0; j < N; j++)
     res(j,i) = this->_coord[i * N + j];
   return res;
  }

  inline void getArray(value_type res[M][N]) const {
   for (unsigned i = 0; i < M; i++)
    for (unsigned j = 0; j < N; j++)
     res[i][j] = this->_coord[i * N + j];
  }

  inline void getArray(value_type res[_SIZE]) const {
   for (unsigned i = 0; i < _SIZE; i++)
    res[i] = this->_coord[i];
  }

  inline const value_type* address() const {
   return this->_coord;
  }

  template <class U>
  inline Matrix<T, M, N>& operator=(const Matrix<U, M, N>& m) {
   if (this != &m)
    for (unsigned i = 0; i < M; i++)
     for (unsigned j = 0; j < N; j++)
      this->_coord[i * N + j] = (T)m(i, j);
   return *this;
  }

  template <class U>
  inline Matrix<T, M, N>& operator+=(const Matrix<U, M, N>& m) {
   for (unsigned i = 0; i < M; i++)
    for (unsigned j = 0; j < N; j++)
     this->_coord[i * N + j] += (T)m(i, j);
   return *this;
  }

  template <class U>
  inline Matrix<T, M, N>& operator-=(const Matrix<U, M, N>& m) {
   for (unsigned i = 0; i < M; i++)
    for (unsigned j = 0; j < N; j++)
     this->_coord[i * N + j] -= (T)m(i, j);
   return *this;
  }

  template <class U>
  inline Matrix<T, M, N>& operator*=(const U lambda) {
   for (unsigned i = 0; i < M; i++)
    for (unsigned j = 0; j < N; j++)
     this->_coord[i * N + j] *= lambda;
   return *this;
  }

  template <class U>
  inline Matrix<T, M, N>& operator/=(const U lambda) {
   if (lambda)
    for (unsigned i = 0; i < M; i++)
     for (unsigned j = 0; j < N; j++)
      this->_coord[i * N + j] /= lambda;
   return *this;
  }

 protected:

  value_type _coord[_SIZE];
 };

 //
 //  SquareMatrix class
 //    - T: value type
 //    - N: rows & cols
 //
 /////////////////////////////////////////////////////////////////////////////

 // Dirty, but icc under Windows needs this
# define __SIZE (N * N)

 template <class T, unsigned N>
 class SquareMatrix : public Matrix<T, N, N>
 {
 public:

  typedef T value_type;

  inline SquareMatrix() : Matrix<T, N, N>() {}

  template <class U>
  explicit inline SquareMatrix(const U tab[__SIZE]) : Matrix<T, N, N>(tab) {}

  template <class U>
  explicit inline SquareMatrix(const std::vector<U>& tab) : Matrix<T, N, N>(tab) {}

  template <class U>
  inline SquareMatrix(const Matrix<U, N, N>& m) : Matrix<T, N, N>(m) {}

  static inline SquareMatrix<T, N> identity() {
   SquareMatrix<T, N> res;
   for (unsigned i = 0; i < N; i++)
    res(i, i) = 1;
   return res;
  }
 };

 //
 // Vector external functions
 //
 /////////////////////////////////////////////////////////////////////////////

 template <class T, unsigned N>
 inline Vector<T, N> operator+(const Vector<T, N>& v1,
  const Vector<T, N>& v2) {
   Vector<T, N> res(v1);
   res += v2;
   return res;
 }

 template <class T, unsigned N>
 inline Vector<T, N> operator-(const Vector<T, N>& v1,
  const Vector<T, N>& v2) {
   Vector<T, N> res(v1);
   res -= v2;
   return res;
 }
 template <class T, unsigned N>
 inline Vector<T, N> operator*(const Vector<T, N>& v,
  const typename Vector<T, N>::value_type r) {
   Vector<T, N> res(v);
   res *= r;
   return res;
 }

 template <class T, unsigned N>
 inline Vector<T, N> operator*(const typename Vector<T, N>::value_type r,
  const Vector<T, N>& v) {
   Vector<T, N> res(v);
   res *= r;
   return res;
 }

 template <class T, unsigned N>
 inline Vector<T, N> operator/(const Vector<T, N>& v,
  const typename Vector<T, N>::value_type r) {
   Vector<T, N> res(v);
   if (r)
    res /= r;
   return res;
 }

 // dot product
 template <class T, unsigned N>
 inline typename Vector<T, N>::value_type operator*(const Vector<T, N>& v1,
  const Vector<T, N>& v2) {
   typename Vector<T, N>::value_type sum = 0;
   for (unsigned i = 0; i < N; i++)
    sum += v1[i] * v2[i];
   return sum;
 }

 // cross product for 3D Vectors
 template <typename T>
 inline Vec3<T> operator^(const Vector<T, 3>& v1,
  const Vector<T, 3>& v2) {
   Vec3<T> res(v1[1] * v2[2] - v1[2] * v2[1],
    v1[2] * v2[0] - v1[0] * v2[2],
    v1[0] * v2[1] - v1[1] * v2[0]);
   return res;
 }

 // stream operator
 template <class T, unsigned N>
 inline std::ostream& operator<<(std::ostream& s,
  const Vector<T, N>& v) {
   unsigned i;
   s << "[";
   for (i = 0; i < N - 1; i++)
    s << v[i] << ", ";
   s << v[i] << "]";
   return s;
 }

 //
 // Matrix external functions
 //
 /////////////////////////////////////////////////////////////////////////////

 template <class T, unsigned M, unsigned N>
 inline Matrix<T, M, N>
  operator+(const Matrix<T, M, N>& m1,
  const Matrix<T, M, N>& m2) {
   Matrix<T, M, N> res(m1);
   res += m2;
   return res;
 }

 template <class T, unsigned M, unsigned N>
 inline Matrix<T, M, N>
  operator-(const Matrix<T, M, N>& m1,
  const Matrix<T, M, N>& m2) {
   Matrix<T, M, N> res(m1);
   res -= m2;
   return res;
 }

 template <class T, unsigned M, unsigned N>
 inline Matrix<T, M, N>
  operator*(const Matrix<T, M, N>& m1,
  const typename Matrix<T, M, N>::value_type lambda) {
   Matrix<T, M, N> res(m1);
   res *= lambda;
   return res;
 }

 template <class T, unsigned M, unsigned N>
 inline Matrix<T, M, N>
  operator*(const typename Matrix<T, M, N>::value_type lambda,
  const Matrix<T, M, N>& m1) {
   Matrix<T, M, N> res(m1);
   res *= lambda;
   return res;
 }

 template <class T, unsigned M, unsigned N>
 inline Matrix<T, M, N>
  operator/(const Matrix<T, M, N>& m1,
  const typename Matrix<T, M, N>::value_type lambda) {
   Matrix<T, M, N> res(m1);
   res /= lambda;
   return res;
 }

 template <class T, unsigned M, unsigned N, unsigned P>
 inline Matrix<T, M, P>
  operator*(const Matrix<T, M, N>& m1,
  const Matrix<T, N, P>& m2) {
   unsigned i, j, k;
   Matrix<T, M, P> res;
   typename  Matrix<T, N, P>::value_type scale;

   for (j = 0; j < P; j++) {
    for (k = 0; k < N; k++) {
     scale = m2(k, j);
     for (i = 0; i < N; i++)
      res(i, j) += m1(i, k) * scale;
    }
   }
   return res;
 }

 template <class T, unsigned M, unsigned N>
 inline Vector<T, M>
  operator*(const Matrix<T, M, N>& m,
  const Vector<T, N>& v) {

   Vector<T, M> res;
   typename Matrix<T, M, N>::value_type scale;

   for (unsigned j = 0; j < M; j++) {
    scale = v[j];
    for (unsigned i = 0; i < N; i++)
     res[i] += m(i, j) * scale;
   }
   return res;
 }

 // stream operator
 template <class T, unsigned M, unsigned N>
 inline std::ostream& operator<<(std::ostream& s,
  const Matrix<T, M, N>& m) {
   unsigned i, j;
   for (i = 0; i < M; i++) {
    s << "[";
    for (j = 0; j < N - 1; j++)
     s << m(i, j) << ", ";
    s << m(i, j) << "]" << std::endl;
   }
   return s;
 }

} // end of namespace vecmat

#endif // VECMAT_H


原因是在windows的头文件里max，min已经被定义成宏了，所以要出问题!
解决方法：
用
#ifdef max
#undef max
#endif
去掉max的定义。
min同上。

问题解决。

posted @ 2008-11-21 11:21 Alina-zl 阅读(788) | 评论 (0) | 编辑 收藏

CString, QString, char*之间的转换

传给未分配内存的const char* （LPCTSTR）指针.
   CString cstr(asdd);
   const char* ch = (LPCTSTR)cstr;
   ch指向的地址和cstr相同。但由于使用const保证ch不会修改，所以安全.2.传给未分配内存的指针.
    CString cstr = "ASDDSD";
    char *ch = cstr.GetBuffer(cstr1.GetLength() + 1);
    cstr.ReleaseBuffer();
    //修改ch指向的值等于修改cstr里面的值.
    //PS:用完ch后,不用delete ch,因为这样会破坏cstr内部空间,容易造成程序崩溃.
3.第二种用法。把CString 值赋给已分配内存的char *。
    CString cstr1 = "ASDDSD";
    int strLength = cstr1.GetLength() + 1;
    char *pValue = new char[strLength];
    strncpy(pValue, cstr1, strLength);
4.第三种用法.把CString 值赋给已分配内存char[]数组.
    CString cstr2 = "ASDDSD";
    int strLength1 = cstr1.GetLength() + 1;
    char chArray[100];
    memset(chArray,0, sizeof(bool) * 100); //将数组的垃圾内容清空.
    strncpy(chArray, cstr1, strLength1);

如果上述都不行：
CString转换为char*
        CString origCString("Hello, World!");
        wchar_t* wCharString = origCString.GetBuffer(origCString.GetLength()+1);
        size_t origsize = wcslen(wCharString) + 1;
        size_t convertedChars = 0;
        char *CharString;
        CharString=new char(origsize);
        wcstombs_s(&convertedChars, CharString, origsize, wCharString , _TRUNCATE);
        cout << CharString << endl;
成功输出字符串"Hello,World"

原因：
原来在VC++ 2005以前，应用程序默认都是关闭对Unicode的支持的，而在VC2005中，默认打开了对它的支持，CString对应的字符串应该是TCHAR，TCHAR的定义是这样的，
        #ifdef _UNICODE
        typedef wchar_t TCHAR    ;
        #else
        typedef char TCHAR;
        #endif
所以在工程中应该可以关闭对于Unicode的支持，从而可以直接转换。这个做法是右击工程名—〉Property—〉General中的character set中选择notset，这样，本文开头的那段代码就可以正确的执行了。

如何将QString转换为char *或者相反

How can I convert a QString to char* and vice versa ?(trolltech)

Answer:
In order to convert a QString to a char*, then you first need to get a latin1 representation of the string by calling toLatin1() on it which will return a QByteArray. Then call data() on the QByteArray to get a pointer to the data stored in the byte array. See the documentation:

See the following example for a demonstration:

int main(int argc, char **argv)
{
 QApplication app(argc, argv);
 QString str1 = "Test";
 QByteArray ba = str1.toLatin1();
 const char *c_str2 = ba.data();
 printf("str2: %s", c_str2);
 return app.exec();  
}
Note that it is necessary to store the bytearray before you call data() on it, a call like the following
const char *c_str2 = str2.toLatin1().data();

will make the application crash as the QByteArray has not been stored and hence no longer exists.

To convert a char* to a QString you can use the QString constructor that takes a QLatin1String, e.g:

QString string = QString(QLatin1String(c_str2)) ;

 

还有其他多种方法：

方法一 -----------------------------------------
#define G2U(s) ( QTextCodec::codecForName("GBK")->toUnicode(s) )
#define U2G(s) ( QTextCodec::codecForName("GBK")->fromUnicode(s) )

QString str;
QCString cstr;

str = G2U("中文输入");
cstr = U2G(str);

QCString有这样一个重载运算符
operator const char * () const

可以这样
printf("%s\n", (const char*) cstr);
或是copy出来
char buf[1024];
strcpy(buf, (const char*) cstr);

 

方法二 -----------------------------------------
如果是中文系统

直接用   (const char*) str.local8Bit()
例如
printf("%s", (const char*) str.local8Bit());

str是一个QString

方法三 -----------------------------------------
char str[64];
QTextCodec *textcod = QTextCodec::codecForName("GBK");
        QCString string1 = textcod ->fromUnicode(listbox1->currentText());
        strcpy(str,string1);

QString和Std::string

 从char*到 QString可以从fromLocal8Bit()转化
std::string有c_str()的函数使再转化为char*

QString有toAscii()记不清了

你可以看看.

又是我的粗心酿成大错，我重新查看了一下Qt文档，原来Qt可以直接从std::wstring产生一个QString，用QString::fromStdWString(const std::wstring &)这个静态成员函数即可。我试了试用std::string的c_str()返回的char *构造的QString不能再保存原先的中文信息，而用std::wstring构造的QString则可以用qDebug()输出原先的中文信息
GB编码与UTF8编码的转换
在主函数app后加上这句：

QUOTE:

QTextCodec::setCodecForLocale(QTextCodec::codecForName("GB18030"));

 

然后是从UTF8编码到GB编码的字符串转换方法：

QUOTE:

QString Utf8_To_GB(QString strText)
{
    return QString::fromUtf8(strText.toLocal8Bit().data());
}

 

至于从GB到UTF8，那大家就经常用了：

QUOTE:

QString GB_To_Utf8(char *strText)
{
    return QString::fromLocal8Bit(strText);
}

posted @ 2008-11-19 21:39 Alina-zl 阅读(13243) | 评论 (1) | 编辑 收藏