从一开始学习C语言就一直在黑乎乎的控制台程序转悠，虽然一直很有成就感，可一直觉得怪怪的，于是开始尝试做一下带图形界面的程序，毕竟接触的是C，所以自然而然选择了Windows程序设计，我设计的是非常非常简单的程序，就是把33到126的字符错位然后对应输出，就相当于给字符加密了。一开始用控制台程序写完整体代码，然后百度到一个简单的Windows对话框程序，照猫画虎，我直接复制别人的代码然后开始理解代码的意思，最先看懂的部分是case IDOK，我知道当触发OK键的时候执行下面代码，于是我开始找如何获取控件内容的函数GetDlgItemText();尽管找到了这个函数，可是百度到的东西还是看不懂，传递实参的时候总是匹配不到该类型，问同学才知道有字符集UNICODE这个东西，所以我不能直接传字符串，我于是在这个陷阱停留了很久很久，直到我想到把UNICODE这个东西取消。
取消UNICODE之后，可以直接传递字符串，接下来是输出字符串，因为一开始我只想实现输入和输出，并没有考虑加入我的加密代码，这是我的编程习惯，简化编程内容，一步一步增加代码，先确保部分代码不出错，再整合代码。在输出控件的时候又出现了问题，就是Sratic control这个控件，一直出现未定义的报错，后来百度到需要更改这个控件的名字才可以使用。
#include <windows.h>
#include "resource.h"
BOOL CALLBACK DlgMain(HWND, UINT, WPARAM, LPARAM);//HWND窗口句柄
int strlength(char * str)
{//字符串长度判断
int a = 0;
while (*str++ != '\0')
a++;
return(a);
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd)
{//主函数，从这里开始执行,调用DialogBox函数MAKEINTRESOURCE(IDD_DIALOG1),括号内是对话框的名称
DialogBox(hInstance, MAKEINTRESOURCE(IDD_DIALOG1), NULL, DlgMain);
return 0;
}
//CALLBACK回调函数
BOOL CALLBACK DlgMain(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)
{
case WM_CLOSE:
{//当点击×时候执行结束函数
EndDialog(hwnd, 0);
return 0;
}
case WM_COMMAND:
{
switch (LOWORD(wParam))
{
case IDOK:
{//当点击OK按钮时
int cnum = 0, i = 0;
char str[30];
char error[] = "Please enter letters,numbers,or common characters.";
char item[] = "ERROR";
GetDlgItemText(hwnd, IDC_EDIT1, str, 30);//获得edit control控件内的内容保存在字符串str内，并且由于更改过UNICODE可以使用字符串，
cnum = strlength(str);//如何更改UNICODE：项目右键-属性-配置属性-常规-项目默认值-字符集
for (; i < cnum; i++)//判断是否存在非法字符 例如中文
if (str[i] < 33 || str[i] > 126){
MessageBox(hwnd, error, item, 0);//弹出消息框内容为error标题item
return 0;
}
for (i = 0; i < cnum; i++){
switch (str[i])
{
case 33:
str[i] = 57;
break;
case 34:
str[i] = 58;
break;
case 35:
str[i] = 59;
break;
case 36:
str[i] = 60;
break;
case 37:
str[i] = 61;
break;
case 38:
str[i] = 62;
break;
case 39:
str[i] = 63;
break;
case 40:
str[i] = 64;
break;
case 41:
str[i] = 65;
break;
case 42:
str[i] = 66;
break;
case 43:
str[i] = 67;
break;
case 44:
str[i] = 68;
break;
case 45:
str[i] = 69;
break;
case 46:
str[i] = 70;
break;
case 47:
str[i] = 71;
break;
case 48:
str[i] = 72;
break;
case 49:
str[i] = 73;
break;
case 50:
str[i] = 74;
break;
case 51:
str[i] = 75;
break;
case 52:
str[i] = 76;
break;
case 53:
str[i] = 77;
break;
case 54:
str[i] = 78;
break;
case 55:
str[i] = 79;
break;
case 56:
str[i] = 80;
break;
case 57:
str[i] = 33;
break;
case 58:
str[i] = 34;
break;
case 59:
str[i] = 35;
break;
case 60:
str[i] = 36;
break;
case 61:
str[i] = 37;
break;
case 62:
str[i] = 38;
break;
case 63:
str[i] = 39;
break;
case 64:
str[i] = 40;
break;
case 65:
str[i] = 41;
break;
case 66:
str[i] = 42;
break;
case 67:
str[i] = 43;
break;
case 68:
str[i] = 44;
break;
case 69:
str[i] = 45;
break;
case 70:
str[i] = 46;
break;
case 71:
str[i] = 47;
break;
case 72:
str[i] = 48;
break;
case 73:
str[i] = 49;
break;
case 74:
str[i] = 50;
break;
case 75:
str[i] = 51;
break;
case 76:
str[i] = 52;
break;
case 77:
str[i] = 53;
break;
case 78:
str[i] = 54;
break;
case 79:
str[i] = 55;
break;
case 80:
str[i] = 56;
break;
case 81:
str[i] = 104;
break;
case 82:
str[i] = 105;
break;
case 83:
str[i] = 106;
break;
case 84:
str[i] = 107;
break;
case 85:
str[i] = 108;
break;
case 86:
str[i] = 109;
break;
case 87:
str[i] = 110;
break;
case 88:
str[i] = 111;
break;
case 89:
str[i] = 112;
break;
case 90:
str[i] = 113;
break;
case 91:
str[i] = 114;
break;
case 92:
str[i] = 115;
break;
case 93:
str[i] = 116;
break;
case 94:
str[i] = 117;
break;
case 95:
str[i] = 118;
break;
case 96:
str[i] = 119;
break;
case 97:
str[i] = 120;
break;
case 98:
str[i] = 121;
break;
case 99:
str[i] = 122;
break;
case 100:
str[i] = 123;
break;
case 101:
str[i] = 124;
break;
case 102:
str[i] = 125;
break;
case 103:
str[i] = 126;
break;
case 104:
str[i] = 81;
break;
case 105:
str[i] = 82;
break;
case 106:
str[i] = 83;
break;
case 107:
str[i] = 84;
break;
case 108:
str[i] = 85;
break;
case 109:
str[i] = 86;
break;
case 110:
str[i] = 87;
break;
case 111:
str[i] = 88;
break;
case 112:
str[i] = 89;
break;
case 113:
str[i] = 90;
break;
case 114:
str[i] = 91;
break;
case 115:
str[i] = 92;
break;
case 116:
str[i] = 93;
break;
case 117:
str[i] = 94;
break;
case 118:
str[i] = 95;
break;
case 119:
str[i] = 96;
break;
case 120:
str[i] = 97;
break;
case 121:
str[i] = 98;
break;
case 122:
str[i] = 99;
break;
case 123:
str[i] = 100;
break;
case 124:
str[i] = 101;
break;
case 125:
str[i] = 102;
break;
case 126:
str[i] = 103;
break;
default:
break;
}
}
SetDlgItemText(hwnd, 12389, str);//在控件12389输出内容str，必须更改该控件的名称才能输出
return 0;
}
}
}
}
return FALSE;
}