Re: Edit Control - C / C++ / MFC Discussion Boards

Re: Edit Control

Trupti Mehta5-Jun-08 2:39

Trupti Mehta

5-Jun-08 2:39

Jijo raj wrote:
CString csValue;GetDlgItem(IDC_EDIT1)->GetWindowText( csValue );double dValue = atof( csValue );

The above code gives me error :
error C2440: 'type cast' : cannot convert from 'class CString' to 'char *'
No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called

in eVc++4.

How do I solve this error.

Thanks

Terry

Re: Edit Control

Jijo.Raj5-Jun-08 3:01

Jijo.Raj

5-Jun-08 3:01

Try this.

double dValue = atof((LPCTSTR)csValue );

The previous code snippet compiles perfectly in Visual Studio 6.0. Might be you got the error because of eVc++4.

Regards,
Jijo.

_____________________________________________________

http://weseetips.com[^] Visual C++ tips and tricks. Updated daily.

Re: Edit Control

David Crow5-Jun-08 3:18

David Crow

5-Jun-08 3:18

Jijo raj wrote:
double dValue = atof((LPCTSTR)csValue );

Redundant cast.

"Love people and use things, not love things and use people." - Unknown

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

Re: Edit Control

Trupti Mehta5-Jun-08 3:52

Trupti Mehta

5-Jun-08 3:52

On trying you code you provided, I get :

Jijo raj wrote:
double dValue = atof((LPCTSTR)csValue );

: error C2664: 'atoi' : cannot convert parameter 1 from 'const unsigned short *' to 'const char *'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
Error executing cl.exe.

I am working with eVC++4 on WinCE MFC application. Hope to find some alternative to the problem.

Thanks

Terry

Re: Edit Control

Trupti Mehta5-Jun-08 21:56

Trupti Mehta

5-Jun-08 21:56

Jijo, got it working as :

<pre>
	CString csValue;
	GetDlgItem(IDC_OpNo_EDIT)-&gt;GetWindowText( csValue );
	int no = atoi((char*)(LPCTSTR)csValue);
</pre>

And guess what, on appling to 1 UpdateData, 1 Assertion Failure is gone. Still other are their. Thinking to apply the same technique wherever using UpdateData & get rid of the errors & get working done.

For building an application for Win CE device that supports Embedded VC++ & .NET 2003. Is developing in 2003 VC++ much easier than working with eVc++? Asking as I am getting such errors & problems with eVC. Will the same or similar arise with 2003 VC also?

Thanks for all your efforts.

Thanks

Terry

Re: Edit Control

David Crow5-Jun-08 3:18

David Crow

5-Jun-08 3:18

The error has to do with your Unicode settings. You can use _stscanf() which will work with both MBCS and Unicode.

"Love people and use things, not love things and use people." - Unknown

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

Re: Edit Control

Alan Balkany5-Jun-08 4:01

Alan Balkany

5-Jun-08 4:01

You can convert from CString to char* in two steps:

CString str1;
char* str2;

...

str2 = (char *) (const char *) str1;

If I have to do this a lot, I define:

#define STOC(X) ((char *) (const char *) (X))

Where STOC stands for "String to char*".

Re: Edit Control

Trupti Mehta5-Jun-08 4:57

Trupti Mehta

5-Jun-08 4:57

OOps Alan,

CString csValue;
GetDlgItem(IDC_OpNo_EDIT)->GetWindowText( csValue );

char* str2;
str2 = (char*) (const char*)csValue;
char* stopString;

long l = strtol(str2, &stopString, 9);
int i = (int)l;

: error C2440: 'type cast' : cannot convert from 'class CString' to 'const char *'
No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called
Error executing cl.exe.

Can't understand what is the solution for a simple task.
_stscanf() provided by a helpful member is also not supported by eVC++ in CE platform.

The main reason for doing this conversion is the application throws "Assertion Failure" message followed by "An unsupported operation was attempted" on UpdateData. Their is no scope to debug or find the actual error line. On commenting UpdataData, the error/message doesn't come. So am loking some way to do casting by getting the text via GetWindowText() which by default returns CString only.

I appreciate everybody's help, but still need help to get rid of error messages & make it working one way or the other. Hope to get help.

Thanks

Terry

Re: Edit Control

Alan Balkany5-Jun-08 5:05

Alan Balkany

5-Jun-08 5:05

You probably have UNICODE defined, so substitute wchar_t for char in the example and it will work perfectly.

Re: Edit Control

Trupti Mehta5-Jun-08 21:50

Trupti Mehta

5-Jun-08 21:50

UNICODE is not in the picture at all.
Got it working as expected. None of the above worked. The correct solution found is :

CString csValue;
GetDlgItem(IDC_OpNo_EDIT)->GetWindowText( csValue );
int no = atoi((char*)(LPCTSTR)csValue);

Thanks to all of you for all of your support & efforts.

Thanks

Terry

Re: Edit Control

Alan Balkany6-Jun-08 3:15

Alan Balkany

6-Jun-08 3:15

FYI, LPCTSTR is another name for const char*, according to

http://www.codeguru.com/forum/archive/index.php/t-78509.html[^]

which is what I suggested previously.

Re: Edit Control

toxcct5-Jun-08 0:02

toxcct

5-Jun-08 0:02

several ways.

either you get the full content as a string, then you cast it to an integer youself, or you can also map an integer variable to your edit control.

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Re: Edit Control

Rajesh R Subramanian5-Jun-08 0:15

Rajesh R Subramanian

5-Jun-08 0:15

See GetDlgItemInt()[^] and GetWindowText()[^]

Or use a member variable and call UpdateData(true) (The last thing you should be doing, if you know what it does).

Nobody can give you wiser advice than yourself. - Cicero
.·´¯`·->Rajesh<-·´¯`·.
Codeproject.com: Visual C++ MVP

Re: Edit Control

sudhir_Kumar5-Jun-08 0:33

sudhir_Kumar

5-Jun-08 0:33

Attach int variable with edit control with the help of class Wizard.

-@SuDhIrKuMaR@-

Re: Edit Control

sudhir_Kumar5-Jun-08 0:35

sudhir_Kumar

5-Jun-08 0:35

You can also attach double variable for DDX.

-@SuDhIrKuMaR@-

Re: Edit Control

James R. Twine5-Jun-08 1:11

James R. Twine

5-Jun-08 1:11

   If you are not filtering the allowable characters in the edit control, you may have cases where users enter data that cannot be converted to a double. For example, 12345.65a, abc123, 123..4, etc.

   While I would suggest getting the text from the control and then converting it to a double, I would use strtod(...)/_tcstod(...)/wcstod(...) instead. It provides a way to tell you what character causes conversion to fail, which can be used to provide automatic error handling (i.e. ignore any invalid characters), or to provide a more helpful error message to the user.

   Peace!

-=- James
Please rate this message - let me know if I helped or not!<hr></hr>If you think it costs a lot to do it right, just wait until you find out how much it costs to do it wrong!
Remember that Professional Driver on Closed Course does not mean your Dumb Ass on a Public Road!
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Re: Edit Control

Trupti Mehta5-Jun-08 4:21

Trupti Mehta

5-Jun-08 4:21

Thanks James. But still not to the mark. Actually I want to convert CString to int. So, based on your hint, I opted to use strtol and then cast it to int, as i didn't find any method that converts strtoi.

CString csValue;
GetDlgItem(IDC_OpNo_EDIT)->GetWindowText( csValue );   // Get the value of text box
LPTSTR p = csValue.GetBuffer(10);    // NEED THIS TO CONVERT TO CHAR* TO USE IN strtol
char* stopString;

long l = strtol(p, stopString, 9);  // GET ERROR DUE TO lptsrt & NOT CHAR*
csValue.ReleaseBuffer();
double d = atof((LPCTSTR)csValue);

The error is :
: error C2664: 'strtol' : cannot convert parameter 1 from 'unsigned short *' to 'const char *'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
Error executing cl.exe.

atof also gives the same error.

aNY WAY to convert LPTSTR ot CString to char*, TCHAR* or wCHAR*.

Thanks

Terry

Re: Edit Control

James R. Twine5-Jun-08 6:47

James R. Twine

5-Jun-08 6:47

Change the function to wcstod or _tcstod, if you are straight Unicode or TCHAR-based building as Unicode, respectively.

PEace!

Re: Edit Control

David Crow5-Jun-08 2:45

David Crow

5-Jun-08 2:45

See here.

"Love people and use things, not love things and use people." - Unknown

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

Question on accessing variable within innerblock?

Super Hornet4-Jun-08 23:54

Super Hornet

4-Jun-08 23:54

#include "iostream.h"


int x = 10;

int main()
{
	int x = 8;

	{
		int x = 5;
		cout << x << ::x ;
		//can we access the value of x which is defined as int x = 8 here?	}

	return 0;
}

Re: Question on accessing variable within innerblock?

toxcct5-Jun-08 0:00

toxcct

5-Jun-08 0:00

~~yes, that's what cout << x does~~ you updated your post, so now, the answer is no.

you can only access a most inner variable (by using its name) or accessing the global variable by prepending its name with the global scope operator ( :: ).

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Re: Question on accessing variable within innerblock?

CPallini5-Jun-08 0:11

CPallini

5-Jun-08 0:11

As posted you question is ambiguous.
Anyway the following one is clear

Super Hornet wrote:
//can we access the value of x which is defined as int x = 8 here?

and the answer is (AFAIK ) no: the inner x hides the outer one.
Smile | :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

Re: Question on accessing variable within innerblock?

sudhir_Kumar5-Jun-08 0:29

sudhir_Kumar

5-Jun-08 0:29

No you Can't the value with ::x will be the value from the global namespace. Smile | :)

-@SuDhIrKuMaR@-

Re: Question on accessing variable within innerblock?

Nibu babu thomas5-Jun-08 0:58

Nibu babu thomas

5-Jun-08 0:58

Super Hornet wrote:
//can we access the value of x which is defined as int x = 8 here?

If you badly need it then rename inner x to something else or store the previous x(main) in some variable before you declare the most inner x and use that variable.

This is not the optimal way for naming variables. You can easily give different names. Or is this an interview question?

Nibu thomas
Microsoft MVP for VC++

Code must be written to be read, not by the compiler, but by another human being.

Programming Blog: http://nibuthomas.wordpress.com

Re: Question on accessing variable within innerblock?

Eytukan5-Jun-08 1:58

Eytukan

5-Jun-08 1:58

#include "iostream.h"
int x = 10;
int y;
int main()
{	
int x = 8;
y = x;
{	
int x = 5;		
cout << x << ::x ;		
 USE Y! ;)
//can we access the value of x which is defined as int x = 8 here?
}
return 0;
}

In other words, NO. You cannot do it.

OK,. what country just started work for the day ? The ASP.NET forum is flooded with retarded questions. -Christian Graus

Best wishes to Rexx[^]

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