I am using one xml document in my code to collect a response from different calls that I make inside of my c# code. The program runs in a loop and loads the same xml document with different xml content and stores it in a database.However, on some calls, there will be no output generated and in that case I will need to simply clear out the contents of my xml. What would be the way to do it?
the break down of what i am trying to achieve here:
XmlDocument output = new XmlDocument();
On the first run i will get something like that:
output.LoadXml(#"hello world")
after storing it in the database, I want to clear out the contents of it.
Thanks for your help!
As #Fabio said you could just sent it to a new instance of an XmlDocument. Another solution would be to set the InnerText property to an empty string.
output.InnerText = string.Empty;
This would effectively clear out the document.
Related
I'm currently writing a function to save and read data to/from and XML document through
LINQ. Currently I can write the document just fine, but if I go to add data to an existing item, it simply adds a new item. My goal is to create an address book type system (yes I know there's 1000 out there, it's just a learning project for myself) and I've tried ini and basic text but it seems that XML is the best way to go short of using a local DB like sql. Currently I have:
XDocument doc = XDocument.Load(#"C:\TextXML.xml");
var data = new XElement("Entry",
new XElement("Name", textBox1.Text),
new XElement("Address", richTextBox2.Text),
new XElement("Comments", richTextBox1.Text));
doc.Element("Contacts").Add(data);
doc.Save(#"C:\TextXML.xml");
I searched SO and can't seem to find how to append/replace.
Now this saves everything properly, even when I add to the document, but if I want to update an entry I'm not sure how to without creating a new "Entry" nor am have I gotten the knack of removing one. (I'm somewhat new to C# still and self-taught so pardon anything obvious I've overlooked.)
My second issues revolves around loading the information into textboxes.
I'm able to load a list of Entry names into a listbox, but when I go to open the information from that entry I'm not sure how to properly get the nested info.
With the example above I'd need something similar to the following:
XDocument doc = XDocument.Load(#"C:\TextXML.xml");
boxName.Text = The name from the SelectedItem of the list box.
boxAddress.Text = The address child of the element named above etc.
Each method I've tried I wind up with a null reference exception, which tells me I'm not pointing to the right thing, but I'm not sure how to get to those things properly.
I've also tried creating a string and var of the SelectedItem from the list box to help with the naming, and using ToString methods, but still can't figure it out.
For replacing values, there are several functions you can use in XElement:
Value (property with a public setter)
SetValue()
SetElementValue()
SetAttributeValue()
ReplaceWith()
ReplaceNodes()
For example, if you wanted to replace the value in Name:
data.Element("Name").SetValue("NewValue");
or
data.Element("Name").Value = "NewValue";
For loading, once you have the XElement node you desire, then it's as simple as doing
xelement.Value
Or if it's an attribute:
xelement.Attribute("AttributeName").Value
Using your code as an example:
boxName.Text = doc.Element("Entry").Element("Name").Value;
Edit to address comment:
If I'm reading your comment right, you're wanting to extract the Name/Address/etc. data from all the nodes within the Contacts main node?
If so, then you would probably want something like this:
boxName.Text = string.Join(",", doc.Elements("Entry").Select(x => x.Element("Name").Value));
This will give you a single string that has all the names in all Entries separated by a comma. Just change "Name" to "Address" to do the same for addresses.
I'd suggest doing a search for Linq to XML for finding more information about how to use this parsing.
I have an app which should read the data from an xml file and then use that data.
How can I import an xml file in my app (what's the code for that) and how can I use the data from that xml file?
Here's an example of the xml database I use:
<Data>
<Animals>
<A>
<word>Ant</word>
<word>Aardwark</word>
</A>
<B>
<word>Bear</word>
<word>Boa</word>
</B>
</Animals>
</Data>
Also I tried this
XDocument loadedData = XDocument.Load("Data.xml");
to read the data from the xml file but didn't work.
Also the in what form can I use the xml data? In other words the xml data would be in a string format or an "X-Something" format?
Update: Maybe Xml Deserialization would work for me?
Thank you in advance
If "Data.xml" is in the root of the project, make sure the Build Action is set to Content and your code should work.
Linq2XML is your friend, and will help you do just that! Mind you that it'll be read-only, unless you place it in the Isolated Storage.
No need for IsoStore if you already have the file and it is the same for every app instance (given that you only need to read it). Simply do what Matt said to quickly get the contents. I would recommend deserializing it to a separate class, so that you can easily reuse and modify the data.
Now, if you want to store the data, you can later easily serialize the existing class and store it locally. In case you want to go a bit deeper into data storage, you could use SQL CE, that is included in Mango and will allow you to manipulate SDF files (which, by the way, can be loaded separately with app instances). Also, a good idea would be to look into Sterling DB (will use IsoStore).
Using the System.XML namespace, use the following code.
XmlDocument xml = new XmlDocument();
xml.LoadXml("your string of xml");
XmlNode xNode = xml.SelectSingleNode("xpath to a single node");
XmlNodeList xNodeList = xml.SelectNodes("xpath to multiple nodes");
You can treat xNode and xNodeList kind of like array results sets and view their contents using the bracket syntax like xNodeList[0].
I have two XML files which need to be merged into one file. When I try to merge them, I get an error saying that one of them does not conform.
The offending XML file looks something like:
<letter>
<to>
<participant>
<name>Joe Bethersonton</name>
<PostalAddress>Apartment 23R, 11454 Pruter Street</PostalAddress>
<Town>Fargo, North Dakota, USA</Town>
<ZipCode>50504</ZipCode>
</participant>
</to>
<from>
<participant>
<name>Jon Doe</name>
<PostalAddress>52 Generic Street</PostalAddress>
<Town>Romford, Essex, UK</Town>
<ZipCode>RM11 2TH</ZipCode>
</participant>
</from>
</letter>
I am trying to merge the two files using the following code snippet:
try
{
Dataset ds = new DataSet();
Dataset ds2 = new DataSet();
XmlTextReader reader1 = new XmlTextReader("C:\\File1.xml");
XmlTextReader reader2 = new XmlTextReader("C:\\File2.xml");
ds.ReadXml(reader1);
ds2.ReadXml(reader2);
ds.Merge(ds2);
}
catch(System.Exception ex)
{
Console.WriteLine(ex.Message);
}
This gives the following error:
The same table 'participant' cannot be the child table in two nested relations.
The two XML files are both encoded in UTF-16, which makes combining them by a simple text read and write difficult.
My required end result is one XML file with the contents of the first XML file followed by the contents of the second XML file, with a and tag around the whole lot and a header at the top.
Any ideas?
Thanks,
Rik
In my opinion, the XML you provided is just fine. I suggest, you use the following code and don't use the Dataset class at all:
XDocument doc1 = XDocument.Load("C:\\File1.xml");
XDocument doc2 = XDocument.Load("C:\\File2.xml");
var result = new XDocument(new XElement("Root", doc1.Root, doc2.Root));
result will contain a XML document with "Root" as the root tag and then the content of file 1 followed by the content of file 2.
Update:
If you need to use XmlDocument, you can use this code:
XmlDocument doc1 = new XmlDocument();
XmlDocument doc2 = new XmlDocument();
doc1.Load("C:\\File1.xml");
doc2.Load("C:\\File2.xml");
XmlDocument result = new XmlDocument();
result.AppendChild(result.CreateElement("Root"));
result.DocumentElement.AppendChild(result.ImportNode(doc1.DocumentElement, true));
result.DocumentElement.AppendChild(result.ImportNode(doc2.DocumentElement, true));
I suspect the solution is to provide a schema. DataSet.Merge doesn't know what to do with two sets of elements with the same name. It attempts to infer a schema, but that doesn't work out so well here.
According to this thread on MSDN, this is a limitation of the DataSet class:
The DataSet class in .NET 2.0 (Visual Studio 2005) still has the limitation of not supporting different nested tables with the same name. Therefore you will have to introduce an XML transform to pre-process the XML (and schemas) before you load them up into the DataSet.
Of course, the way that's phrased makes it seem like a newer version might have fixed this. Unfortunately, that may not be the case, as the original answer was posted back in 2005.
This knowledge base article seems to indicate that this behavior is "by design", albeit in a slightly different context.
A better explanation of why this behavior is occurring is also given on this thread:
When ADO reads XML into a DataSet, it creates DataTables to contain each type of element it encounters. Each table is uniquely identified by its name. You can't have two different tables named "PayList".
Also, a given table can have any number of parent tables, but only one of its parent relations can be nested - otherwise, a given record would get written to the XML multiple times, as a child of each of its parent rows.
It's extremely convenient that the DataSet's ReadXml method can infer the schema of the DataSet as it reads its input, but the XML has to conform to certain constraints if it's going to be readable. The XML you've got doesn't. So you have two alternatives: you can change the XML, or you can write your own method to populate the DataSet.
If it were me, I'd write an XSLT transform that took the input XML and turned PayList elements into either MatrixPayList or NonMatrixPaylist elements. Then I'd pass its output to the DataSet.
Using XmlDocument or XDocument to read in and manipulate the XML files is another possible workaround. For an example, see Merging two xml files LINQ
I found a solution using Serialization to first infer the schema,
then serialize the schema and remove the relationships contraints (this tricks the DataSet into thinking that IT has created the dataset.), then load this new schema into a DataSet.
This new dataset will be able to load both your xml files.
More details behind this trick:
Serialization Issue when using WriteXML method
How to write the contents of the "XmlNodeList" in a separate xml file(ie.,the contents should be appended at the end of a file,if the file already contains some text)?
If you know the XML ( I assume you do!) you can do the following steps:
Create XmlDocument object of the file you need to modify
Create the XmlNodeList ready ( you have that already)
Use the AppendChild, InsertAfter or InsertBerfore methods ( these methods accept only XmlNode so you will have to iterate)
Save the XmlDocument
Hope this helps,
Regards,
Abdel Olakara
Load the XML document. Find the node where you want to insert new block. Insert the block. Write the XML to the file.
Use XmlDocument class for this purpose. Check MSDN for examples.
I am using windows application and I have four combo boxes(comboeventname,combosendtype,comboType,comboschedule) in that form.... I have stored that combo values in to XML file by using XML writer...
Now I want to display the data in that combo boxes in form load event when form opens in run time... How to retrieve that values from that XML file and how to display that data in combo boxes while run time? How shall I do this?
Anyone tell me the solution of this.....
Thanks in Advance...
We can probably get XmlReader working if you show the xml or the code you used to write it, but I'm not sure that is the best option here. Presumably, to display them in a combobox the data-volume isn't immense. In that case, it would be much simpler to use any of:
XmlDocument
XDocument
XmlSerializer
etc to load the data into a DOM or object-model, and work from their. LINQ-to-XML (via XDocument) may be particularly appealing. For example, with the xml:
<options>
<option value='123'>ABC</option>
<option value='234'>DEF</option>
<option value='567'>GHI</option>
</options>
The XDocument code like below may work:
var options =
from option in XElement.Parse(xml).Elements("option")
select new {
value = (int)option.Attribute("value"),
text = option.Value
};
Probably much easier to use XmlDocument , or XDocument.
XmlDocument:
http://msdn.microsoft.com/en-us/library/system.xml.xmldocument.selectsinglenode.aspx
private void Form1_Load(object sender, EventArgs e)
{
//load the xml document;
XmlDocument xdoc = new XmlDocument;
xdoc.Load("YourFile.xml");
// read the values
// using indexers
method1 = xdoc["root"]["Element"].Value;
// using xpath to select nodes
method2 = xdoc.SelectSingleNode( "root/element/element" ).Value;
// attributes
method3 = xdoc.SelectSingleNode("root/element").Attributes["YourAttribute"].Value;
}
XmlReader is better used for large XML files, 1000s of elements, where you don't want to load the whole document into memory. Your document sound far to small to use XmlReader.
I'd suggest using an XmlReader. There's a lot of documentation around but here's a start:
http://msdn.microsoft.com/en-us/library/9d83k261%28VS.80%29.aspx
Once you have the data you can add them to the your form controls.
Alternatively you could use an XmlDocument - although it does not perform as well as the XmlReader I doubt you will notice with this situation.
I have used before xsd mappings to generate class mappings for an xml document.
On visual studio command prompt line use xsd commands like below .
This will generate mapping class and then
you should deserialize xml file to object and cast to generated mapping class.
xsd "path of xml file" this genarates xsd file
than command promt again
xsd "pat of generated xsd file" /CLASSES
for details look at that sample