Error with SetValue()

[fly2c]

Hi

I try to use SetValue() to set a new text for an element but get an error.

my empty tag at the beginning is:

<ph_res></ph_res>

Now I try to set a value for "ph_res", e.g. "55"

So my code looks like this:

//got a CString with value "55"
CString temp = getCString();
USES Conversion;
const char* value;
value = T2A(temp);

TiXmlText* text = docHandle.ChildElement("ph_res",0).FirstChild().Text();
text->SetValue(value);

When I starts my Console Application, it crashes at "SetValue"
The Debugger says the error shows to "tinystr.h" at:

//Return the length of a TiXmlString
size_type length () const {return rep_->size; }

"Unhandled exception: 0xC00000005: Access Violation"

Same error occurs when I try:
text->SetValue("55");

Please can anybody help?

[fly2c]

When I use STL the error is gone but nothing is working well. Can it be a STL error or anything like this?

[Lee Thomason]

fly2c --

The FirstChild() isn't a TiXmlText - it is a TiXmlElement. The Text() function therefore returns null, and 'text' is null, and calling the method of a a null pointer is a Bad Thing. :)

Also, Text() is deprecated in favor of ToText().

lee

[fly2c]

Thanks for your answer

I changed the code to:

TiXmlText* text = docHandle.ChildElement("ph_res",0).FirstChild().ToText();
text->SetValue("55");

... but the problem still exists.

I tried another xml file and there occurs the same error with SetValue().
I must compile with the UNICODE compiler option. Can this be an error reason?

[Lee Thomason]

There is no TiXmlText node in your XML at all. You will never be able to get a pointer to something that doesn't exist. The FirstChild() is a TiXmlElement, not text.

If you want to add a text node, InsertEndChild( text ) on the Element.

typing from memory (untested):
TiXmlElement* element = docHandle.ChildElement("ph_res",0).ToElement();
TiXmlText text( "55" );
element->InsertEndChild( text );

lee

[fly2c]

I tried it out, but

element->InsertEndChild() wants a TiXmlNode, not a TiXmlText. So I get an error for: element->InsertEndChild(text);

I can't really understand. In the "help" there exactly the same examples, but it doesn't work.

[fly2c]

I found a solution.

I go through the xml document and set "node" on the element that I will change. I take for this:

TiXmlDocument doc(pathname);

//after loading

TiXmlNode* node = 0;
node = doc.RootElement(); // node is root
node = node->FirstChild();

while(strcmp(node->Value(), "ph_res") != 0) //look for ph_res node
{
node = node->NextSibling();
}

When I reached the element:

TiXmlElement* element = node->ToElement();
TiXmlText text ( "55");
element->InsertEndChild(text);

... and it works.

Thanks for your help!