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C++ Button Enable\Disable Issue

General and Gameplay Programming Programming

Started by PyroBlizzard June 08, 2005 10:14 PM

4 comments, last by PyroBlizzard 18 years, 10 months ago

PyroBlizzard

122

Author

June 08, 2005 10:14 PM

ok, im about to pull my hair out over this. I have an event handler, supposed to check if a textbox is empty or not, and enable a button if its not empty. Well, it will enable the button, but it wont disable it. Here is the function

private: System::Void tAddressBox_TextChanged(System::Object *  sender, System::EventArgs *  e)
		 {
			 if (!(tAddressBox->Text == ""))
			 {
				 bPingServer->Enabled = true;
				 return;
			 }
			 bPingServer->Enabled = false;
		 }

Now, I know that the code should be right, unless im missing something incredibly obvious. I have even done breakpoints in the debug, and the debugger shows plain as day

Quote:tAddressBox->Text "" String*

So, im lost. I dont know what im doing wrong. Some help, please.

As I lay down, staring up at the stars in all their glory, I wonder.....WHERE THE F*** IS MY ROOF!?!?!?

matthughson

588

June 08, 2005 11:39 PM

So I take it that it never even enters the if statement? Or does it enter but the enable just doesn't work?

Also:

It looks like you're using C#, which I've never used. But I know with C/C++ you have to use a function like strcmp (string compare) when comparing the contents of a string. Otherwise, you'd be comparing "" to the address of that string. But that assumes it's a simple char*, so who knows. Just tossing it out there.

Matt Hughson

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Nemesis2k2

1,045

June 08, 2005 11:52 PM

Yeah, unless tAddressBox->Text is a string object (std::string), you need to use strcmp() or equivelant to compare the strings.

MaulingMonkey

1,729

June 08, 2005 11:57 PM

Quote:Original post by matthughson
So I take it that it never even enters the if statement? Or does it enter but the enable just doesn't work?

Also:

It looks like you're using C#, which I've never used. But I know with C/C++ you have to use a function like strcmp (string compare) when comparing the contents of a string. Otherwise, you'd be comparing "" to the address of that string. But that assumes it's a simple char*, so who knows.

Bolded for emphisis. == works fine if you're using std::string.

I've not used C#/.NET either, but check if there's an "empty()" member of text or similar. It's possible that [empty()] and [== ""] are not quite the same.

JWalsh

498

June 09, 2005 12:00 AM

Actually, PyroBlizzard is using Managed C++ and the string he's using is the System::String class.

The comparison should be written:

if( !tAddressBox->Text->Equals("") )
{
...
}

EDIT:

Or, as MaulingMonkey suggested, you could just use the string's empty attribute

if( !tAddressBox->Text->Empty )
{
...
}

Jeromy Walsh
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PyroBlizzard

122

Author

June 09, 2005 07:29 AM

wow, once again, JWalsh saves the day. Thank you all for your help, I really appreciate it. It was in fact a thing of needing an ->Equals section.

As I lay down, staring up at the stars in all their glory, I wonder.....WHERE THE F*** IS MY ROOF!?!?!?