在IO域中输入一个字符串可以切换趋势，如果输入错误则弹出对话框。
HWND hwnd=NULL;
int iRet;
char a[255];
char b[255];
char c[255];
char d[255];
char * p;
char *str[5]={"A123","A456","A789","AHU110","AHU111"};//初始化数组
int i;

hwnd=FindWindow(NULL,"WinCC-运行系统 - ");
p=GetTagChar("TEXT1"); //Return-Type: char*

Letter_strupr(p); //Return-Type: char*

if (strcmp(p,"AHU")==0)
{
SetPictureName("100_Trend.pdl","画面窗口1","AHU.pdl"); //Return-Type: BOOL
SetVisible(lpszPictureName,"画面窗口1",TRUE); //Return-Type: BOOL
}
else if (strcmp(p,"PAU")==0)
{
SetPictureName("100_Trend.pdl","画面窗口1","PAU.pdl"); //Return-Type: BOOL
SetVisible(lpszPictureName,"画面窗口1",TRUE); //Return-Type: BOOL
}
else

{
for(i=0; i<5;i++)
{
if (strcmp(p,str[i])==0)
{
sprintf(a,"AHU\\%s.SetTemp",p);
sprintf(b,"AHU\\%s.RAT",p);
sprintf(c,"AHU\\%s.SetHum",p);
sprintf(d,"AHU\\%s.RAH",p);
SetPropWord(lpszPictureName,"Control1","TrendIndex",0); //Return-Type: BOOL
SetPropChar(lpszPictureName,"Control1","TrendTagName",a); //Return-Type: BOOL
SetPropWord(lpszPictureName,"Control1","TrendIndex",1); //Return-Type: BOOL
SetPropChar(lpszPictureName,"Control1","TrendTagName",b); //Return-Type: BOOL
SetPropWord(lpszPictureName,"Control1","TrendIndex",2); //Return-Type: BOOL
SetPropChar(lpszPictureName,"Control1","TrendTagName",c); //Return-Type: BOOL
SetPropWord(lpszPictureName,"Control1","TrendIndex",3); //Return-Type: BOOL
SetPropChar(lpszPictureName,"Control1","TrendTagName",d); //Return-Type: BOOL
SetVisible(lpszPictureName,"画面窗口1",FALSE); //Return-Type: BOOL
SetTagWord("A_BPL_BX",i);
goto Exit0;
}
}
iRet=MessageBox(hwnd,"输入错误","系统提示",MB_OK);
}
Exit0:
{}
}