SendMessage and error 0xC0000005

Question

i have a problem at

case IDC_LBPS:
     {
      switch (HIWORD(wParam)) 
      { 
       case LBN_SELCHANGE:
       {
	  	char bName[256];
       
	    SendMessage(LBPS,LB_GETTEXT,SendMessage(LBPS,LB_GETCURSEL,0,0L),(LPARAM)bName);
	    SendMessage(TN,WM_SETTEXT,0,(LPARAM)bName);
		ReadPwrScheme(SendMessage(LBPS,LB_GETCURSEL,0,0L),&pp);
		SendMessage(TV,WM_SETTEXT,0,(LPARAM)(LPCWSTR)pp.user.VideoTimeoutAc);
		        
	 	break; 
       }

	   break;
      }

	  break;
     }

program compiles, but
When i'mtrying to sendmessage to edit control with the powerpolicy.user.VideoTimeoutAc i have an error  "0x7e38c1f9" "MyKursTst.exe": 0xC0000005: "0x00000384".

help please

P.S. Sorry for my english.

Answer 1

pp.user.VideoTimeoutAc what is it?

You got access violation trying to retrieve it.

Answer 2

POWER_POLICY pp;

pp is global variable, and .user.VideoTimeoutAc one of its parametres

Answer 3

What function are you using to fill the POWER_POLICY struct? Check this code.

Place breakpoint on SendMessage and look for VideoTimeoutAc value.

Also, you cannot use VideoTimeoutAc as WM_SETTEXT message param, because it is ULONG. Need to convert to string.

lParam should be pointer to a null-terminated string.

Answer 4

Did you allocate memory for both .user and user.VideoTimeoutAc? Is the memory for VideoTimeoutAc large enough to hold the returning string?

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Answer 5

to fill POWER_POLICY struct i call ReadPwrScheme function.

i think that "(LPCWSTR)" before argument convert argument, or I am not right?

Answer 6

i just disclose variable of POWER_POLICY type...

Answer 7

are there any other ways to realize a conclution of VideoTimeoutAc to edit control?

Answer 8

You need to convert pp.user.VideoTimeoutA to string.

Do something like this:

char *sTemp = new char[256];

itoa(pp.user.VideoTimeoutAc, sTemp, 10);

SendMessage(TV, WM_SETTEXT, 0, (LPARAM)(LPSTR)sTemp);

delete[] sTemp;

Answer 9

Thx,  Nikita L, you helped mr very much.
it's really works...