How to create XElements in XElement with adaptable array length?

Question

0.00/5 (No votes)

See more:

Sorry about the weirdly phrased title, but it was hard to convey my issue in one short sentence.

I'm writing a feature to import CSV-like data into XML. And I'm using a bit more complex code than the MSDN example, but it's essentially the same idea.

Example from MSDN:

C#

string[] source = File.ReadAllLines("customers.csv");
XElement customers = new XElement("Root",
    from str in source
    let fields = str.Split(',')
    select new XElement("Customer",
        new XAttribute("CustomerID", fields[0]),
        new XElement("CompanyName", fields[1]),
        new XElement("ContactName", fields[2]),
        new XElement("ContactTitle", fields[3]),
        new XElement("Phone", fields[4])
    )
);
Console.WriteLine(customers);

The problem is that the files to import have variable number of columns, and have their column names in first row, (I have isolated the first row as a separate array of course), and I would like to "loop through" the array containing column names and add XElements for each of them. However I can't get any standard "looping" to give me the result I want.

I might be missing an obvious solution, but I am fresh out of ideas

Any help would be much appreciated

Posted 13-Jul-15 10:33am

Frank R. Haugen

Add a Solution

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Matt T Heffron · Accepted Answer · 2015-07-13T13:19:00

Do you need to treat one of the columns specially to be the XAttribute instead of XElement? If not, this can be simplified...

C#

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Xml.Linq;

namespace ConsoleApplication6
{
  class Program
  {
    public static Dictionary<TKey, TValue> ZipIntoDictionary<TKey, TValue>(Dictionary<TKey, TValue> dict, IEnumerable<TKey> keys, IEnumerable<TValue> values)
    {
      dict = dict ?? new Dictionary<TKey, TValue>();
      var enumKeys = keys.GetEnumerator();
      var enumValues = values.GetEnumerator();
      while (enumKeys.MoveNext() && enumValues.MoveNext())
      {
        dict.Add(enumKeys.Current, enumValues.Current);
      }
      return dict;
    }

    static void Main(string[] args)
    {
      string filePath = "customers.csv";
      List<string> headers = null;
      const string idKey = "CustomerID";
      Dictionary<string, string> columns = null;
      XElement customers = new XElement("Root");
      using (StreamReader sr = new StreamReader(filePath))
      {
        string line;
        // Read and process lines from the file until the end of the file is reached.
        while ((line = sr.ReadLine()) != null)
        {
          if (string.IsNullOrWhiteSpace(line))
            continue; // ignore blank lines (we've already dealt with null above)
          string[] rawColumns = line.Split(',');
          if (headers == null)
          {
            headers = rawColumns.ToList();  // capture the first non-blank line as headers
            if (!headers.Contains(idKey))   // remove the idKey if there and report if it isn't
            {
              Console.WriteLine("Missing Identifier Key: " + idKey);
              return;
            }
            continue;                       // no more processing of this line
          }

          columns = ZipIntoDictionary(columns, headers, rawColumns);
          XElement thisCustomer = new XElement("Customer", new XAttribute(idKey, columns[idKey]));
          foreach (var pair in columns)
          {
            if (pair.Key != idKey)
              thisCustomer.Add(new XElement(pair.Key, pair.Value));
          }
          customers.Add(thisCustomer);
        }
      }
      Console.WriteLine(customers);
    }
  }
  
}

Most/all of the hard-coded strings could/should be passed as arguments.

[Edit: MTH]
Here it is a bit simplified for no attribute...

C#

static void Main(string[] args)
{
  string filePath = "customers.csv";
  XElement customers = CsvToXml(filePath, "Root", "Customer");
  Console.WriteLine(customers);
}
static XElement CsvToXml(string filePath, string rootName, string elementName)
{
  string[] headers = null;
  XElement root = new XElement(rootName);
  using (StreamReader sr = new StreamReader(filePath))
  {
    string line;
    // Read and process lines from the file until the end of the file is reached.
    while ((line = sr.ReadLine()) != null)
    {
      if (string.IsNullOrWhiteSpace(line))
        continue;           // ignore blank lines (we've already dealt with null above)
      string[] columns = line.Split(',');
      if (headers == null)
      {
        headers = columns;  // capture the first non-blank line as headers
        continue;           // no more processing of this line
      }

      XElement thisElement = new XElement(elementName);
      for (int i = 0; i < headers.Length; i++)
      {
        string value = string.Empty;
        if (i < columns.Length)
          value = columns[i];
        thisElement.Add(new XElement(headers[i], value));
      }
      root.Add(thisElement);
    }
  }
  return root;
}