Reading + Writing XML

[JBudOner]

Im pretty n00bish so im sure it's just a dumb mistake I did. But I can't read the xml and then write something on it.

static string LoadXML(String TheParent, String TheChild)
{
System.IO.StreamReader sr = new System.IO.StreamReader(@"SP.xml");
System.Xml.XmlTextReader xr = new System.Xml.XmlTextReader(sr);
System.Xml.XmlDocument SP = new System.Xml.XmlDocument();
SP.Load(xr);
System.Xml.XmlNodeList SPParent = SP.SelectNodes("XMLDoc/" + TheParent);
System.Xml.XmlNode SPChild = SPParent.Item(0).SelectSingleNode(TheChild);
return SPChild.InnerText;
}

public void WriteXML(String TheParent, String TheChild, String TheValue)
{
System.IO.StreamReader sr = new System.IO.StreamReader(@"SP.xml");
System.Xml.XmlTextReader xr = new System.Xml.XmlTextReader(sr);
System.Xml.XmlDocument SP = new System.Xml.XmlDocument();
SP.Load(xr);
System.Xml.XmlNodeList SPParent = SP.SelectNodes("XMLDoc/" + TheParent);
System.Xml.XmlNode SPChild = SPParent.Item(0).SelectSingleNode(TheChild);

System.Xml.XmlTextWriter Writer = new System.Xml.XmlTextWriter(TheValue, System.Text.UTF8Encoding.UTF8);
SP.WriteTo(Writer);
Writer.Flush();
}






private void button1_Click(object sender, EventArgs e)
{
int TestMe = Int32.Parse(LoadXML("Main", "Subjects")) + 1;
WriteXML("Main", "Subjects", TestMe.ToString());
Label1.Text = LoadXML("Main", "Subjects");
}


There are no errors, I can build it and perform the button click just fine. The XML looks like this:

<XMLDoc>
<Main>
<Subjects>3</Subjects>
</Main>
</XMLDoc>



When I call the button click, Label1.Text says there is still 3 for the subject. I also tried:

private void button1_Click(object sender, EventArgs e)
{
int TestMe = 15;
WriteXML("Main", "Subjects", TestMe.ToString());
Label1.Text = LoadXML("Main", "Subjects");
}


And it still shows 3 in Label1.text.

[JBudOner]

Anyone?

[JBudOner]

Ok I played around with it some more.. Came out to:

static string LoadXML(String TheParent, String TheChild)
{
System.IO.StreamReader sr = new System.IO.StreamReader(@"SP.xml");
System.Xml.XmlTextReader xr = new System.Xml.XmlTextReader(sr);
System.Xml.XmlDocument SP = new System.Xml.XmlDocument();
SP.Load(xr);
System.Xml.XmlNodeList SPParent = SP.SelectNodes("XMLDoc/" + TheParent);
System.Xml.XmlNode SPChild = SPParent.Item(0).SelectSingleNode(TheChild);
return SPChild.InnerText;
}

public void WriteXML(String TheParent, String TheChild, String TheValue)
{
System.IO.StreamReader sr = new System.IO.StreamReader(@"SP.xml");
System.Xml.XmlTextReader xr = new System.Xml.XmlTextReader(sr);
System.Xml.XmlDocument SP = new System.Xml.XmlDocument();
SP.Load(xr);
System.Xml.XmlNodeList SPParent = SP.SelectNodes("XMLDoc/" + TheParent);
System.Xml.XmlNode SPChild = SPParent.Item(0).SelectSingleNode(TheChild);
System.Xml.XmlTextWriter Writer = new System.Xml.XmlTextWriter("SP.xml", System.Text.UTF8Encoding.UTF8);
Writer.WriteStartElement("XMLDoc");
Writer.WriteStartElement(TheParent);
Writer.WriteStartElement(TheChild, TheValue);
SPChild.WriteTo(Writer);
Writer.Flush();
}






private void button1_Click(object sender, EventArgs e)
{
int TestMe = 15;// Int32.Parse(LoadXML("Main", "Subjects")) + 1;
WriteXML("Main", "Subjects", TestMe.ToString());
QsStr.Text = LoadXML("Main", "Subjects");
}



XML is in the debug and it looks like:

<XMLDoc>
<Main>
<Subjects>3</Subjects>
</Main>
</XMLDoc>


So now it's highlighting the line:

System.Xml.XmlTextWriter Writer = new System.Xml.XmlTextWriter("SP.xml", System.Text.UTF8Encoding.UTF8);



And it says that, "The process cannot access the file ... because it is being used by another process." ... Any ideas?

[ideru]

have you tried using XmlDocument and XmlElement?

to load ( i find this easier to use )

XmlDocument doc = new XmlDocument();
doc.Load(filename);

[ideru]

i modified your code a bit

private string LoadXML(String TheParent, String TheChild )
{
		XmlDocument doc = new XmlDocument();
		doc.Load(@"SP.xml");
 
		XmlNode node = doc.DocumentElement;
		string data = "";
		if( node.LocalName == TheParent )
		{
			 IEnumerator rootIter = node.GetEnumerator();
			 while( rootIter.MoveNext() )
			 {
				   XmlNode currentNode = (XmlNode)rootIter.Current;
				   data = currentNode[TheChild ].InnerText;
				   break;
			 }
 
			 return data;
		}
}

[JBudOner]

Aright so I changed my code to match yours, and tried changing the WriteXML() to sorta match the LoadXML() method. Came out to:

public static string LoadXML(String TheParent, String TheChild)
{
System.Xml.XmlDocument doc = new System.Xml.XmlDocument();
doc.Load(@"SP.xml");

System.Xml.XmlNode node = doc.DocumentElement;
string data = "";
{
if (node.LocalName == "XMLDoc")
{
node.SelectSingleNode(TheParent);
System.Collections.IEnumerator rootIter = node.GetEnumerator();
while (rootIter.MoveNext())
{
System.Xml.XmlNode currentNode = (System.Xml.XmlNode)rootIter.Current;
data = currentNode[TheChild].InnerText;
break;
}

//return data;
}
}
return data;
}


public void WriteXML(String TheParent, String TheChild, String TheValue)
{
System.Xml.XmlDocument doc = new System.Xml.XmlDocument();
doc.Load(@"SP.xml");

System.Xml.XmlNode node = doc.DocumentElement;
node.SelectSingleNode(TheParent);
System.Collections.IEnumerator rootIter = node.GetEnumerator();
while (rootIter.MoveNext())
{
System.Xml.XmlNode currentNode = (System.Xml.XmlNode)rootIter.Current;
currentNode[TheChild].SetAttribute(TheChild, TheValue);
break;
}






private void button1_Click(object sender, EventArgs e)
{
int TestMe = 15;// Int32.Parse(LoadXML("Main", "Subjects")) + 1;
WriteXML("Main", "Subjects", TestMe.ToString());
QsStr.Text = LoadXML("Main", "Subjects");
}


...Same thing. The LoadXML() works fine, and i'm even checking the .xml itself, and it isn't changing. Theres no error but it won't write the file. I also checked the debug folder and there is no extra file in there that it may have written to. =( Any ideas or suggestions?

[JBudOner]

Kk I updated it and came out to this:

public static string LoadXML(String TheParent, String TheChild)
{
System.Xml.XmlDocument doc = new System.Xml.XmlDocument();
doc.Load(@"SP.xml");

System.Xml.XmlNode node = doc.DocumentElement;
string data = "";
{
if (node.LocalName == "XMLDoc")
{
node.SelectSingleNode(TheParent);
System.Collections.IEnumerator rootIter = node.GetEnumerator();
while (rootIter.MoveNext())
{
System.Xml.XmlNode currentNode = (System.Xml.XmlNode)rootIter.Current;
data = currentNode[TheChild].InnerText;
break;
}

}
}
return data;
}


public void WriteXML(String TheParent, String TheChild, String TheValue)
{
System.Xml.XmlDocument doc = new System.Xml.XmlDocument();
doc.Load(@"SP.xml");

System.Xml.XmlNode node = doc.DocumentElement;
node.SelectSingleNode(TheParent);node.SelectSingleNode(TheChild);
System.Xml.XmlTextWriter Writer = new System.Xml.XmlTextWriter("SP.xml", System.Text.UTF8Encoding.UTF8);
Writer.WriteString(TheValue);
node.WriteTo(Writer);
doc.Save(@"SP.xml");
}





private void button1_Click(object sender, EventArgs e)
{
WriteXML("Main", "Subjects", "W00000000000T OMG IT WORKS!!!!!!!!!!!!!!!!");
}







And there are no build errors at first. I open it up after I build the prog, and it looks like:

W00000000000T OMG IT WORKS!!!!!!!!!!!!!!!!<XMLDoc><Main><Subjects>3</Subjects></Main></XMLDoc>


when it used to look like:

<XMLDoc>
<Main>
<Subjects>3</Subjects>
</Main>
</XMLDoc>


Then I build it again and there is an error message:

doc.Load(@"SP.xml");


Data at the root level is invalid. Line 1, position 1.








Not sure what this means.. Any ideas? I know LoadXML() works, but I can't figure out how to write my message inside the <Subjects> node. Thx.

[ideru]

sorry i forgot to write, the writing code

private void SetElement(XmlElement settingElement, string path, string value)
{
    if( settingElement[path].InnerText == value)
    {
          settingElement[path].InnerText = value;
     }
     else
     {
                XmlDocument doc = settingElement.OwnerDocument;
                XmlElement newElement = doc.CreateElement(path)
                newElement[path].InnerText = value
      }
    
}

private void WriteXml(string parent, string child, string value)
{
     XmlDocument doc = new XmlDocument();
     doc.Load(filename);

     XmlNode node = doc.DocumentElement;

IEnumerator rootIter = node.GetEnumerator();
     while( rootIter .MoveNext() )
     {
         XmlNode curnode = (XmlNode)rootIter .Current;
         if( curnode.LocalName == child )
         {
             SetElement(curnode, child, value);
             break;
         }
     }

     doc.Save(filename)

}

basically this is how i usually do it. Basically you need also to add some checking in the setting area if ever there is an exception.


// i have not compiled the code above, so there might be some syntax error
// hope it works..

[JBudOner]

Hey, so I played around with it - still having problems. This is what I have:

public void WriteXML(String TheParent, String TheChild, String TheValue)
{
System.Xml.XmlDocument doc = new System.Xml.XmlDocument();
doc.Load(@"SP.xml");

System.Xml.XmlNode node = doc.DocumentElement;

System.Collections.IEnumerator rootIter = node.GetEnumerator();
while( rootIter .MoveNext() )
{
System.Xml.XmlElement curNode = (System.Xml.XmlElement)rootIter.Current;
if (curNode.LocalName == TheChild)
{
SetElement(curNode, TheChild, TheValue);
break;
}
}

doc.Save(@"SP.xml");
}




private void SetElement(System.Xml.XmlElement settingElement, string path, string value)
{
if( settingElement[path].InnerText == value)
{
settingElement[path].InnerText = value;
}
else
{
System.Xml.XmlDocument doc = settingElement.OwnerDocument;
System.Xml.XmlElement newElement = doc.CreateElement(path);
newElement[path].InnerText = value;
}

}





WriteXML("Main", "Subjects", "W00000000000T OMG IT WORKS!!!!!!!!!!!!!!!!");




SP.xml
<XMLDoc>
<Main>
<Subjects>3</Subjects>
<Questions>18</Questions>
<Answered>12</Answered>
<Correct>9</Correct>
</Main>
</XMLDoc>






When I try to build it I get an error on:

if( settingElement[path].InnerText == value) Object reference not set to an instance of an object. Any ideas or suggestions?

[JBudOner]

I got it to work now =)

Check: http://www.dotnetforums.net/showthre...300#post458300