Category Archives: XML

Dynamic LINQ to XML

Language Integrated Query (LINQ) is a cool feature of .NET languages like C# that allows you to perform SQL-like query right within the language against language’s data structures (lists, arrays etc.) But one drawback of LINQ – you have to know in advance, at compile time which fields to select, what filter conditions would be. Sometimes there’s a need to supply these at runtime – e.g. user selects which fields they want to see

Thankfully there exists Dynamic LINQ Library that allows you to supply LINQ parameters as a string akin Dynamic SQL. Here’s an example of such query from the library’s homepage:

var query = db.Customers
    .Where("City == @0 and Orders.Count >= @1", "London", 10)
    .OrderBy("CompanyName")
    .Select("new(CompanyName as Name, Phone)");

Now, one thing that LINQ can do is query XML. So in theory if we load, say, this XML:

<DATA_CENTER>
   <SERVER IP="1.2.3.4">
      <OS>Windows</OS>
   </SERVER>
   <SERVER IP="5.6.7.8">
      <OS>Linux</OS>
   </SERVER>
</DATA_CENTER>

into an XElement and run something like this

var query0 = myXElement.Elements()
          .AsQueryable()
          .Select("new (Attribute(\"IP\").Value as IP, Element(\"OS\").Value as OS)")

it would produce list of IPs and OSes. Unfortunately this doesn’t work. Continue reading →

FusionCharts: Invalid Data when using javascript renderer (solved)

If you’re using FusionCharts you may encounter a strange issue – chart renders correctly when Flash renderer is in use and displays “Invalid Data” error message when falling back (or forced) to JavaScript renderer.

In most cases culprit is invalid XML data passed to the engine. And while Flash is more forgiving, JavaScript requires strict valid XML. Most often the cause for the issue are characters invalid in XML. Check your data and if they contain following characters – replace them with their encoded values:

" (quote) --> &quot;
' (apostrophe) --> &apos;
< (less sign) --> &lt;
> (greater sign) --> &gt;
& (ampersand)  --> &amp;

And the error will disappear.

Happy charting!

FusionCharts: Use non-numeric Xaxis in Bubble and Scatter Charts

FusionCharts states in their documentation that in Bubble and Scatter Charts both X-Axis and Y-Axis must be numeric. But what if you want X-Axis to display some names or dates or other non-numeric values? That is still possible via label attribute of chart’s categories element.

The method below utilizes ADO.NET/VB.NET to build XML for chart data, but similar approach can be easily used in other languages/technologies.

Consider the following ADO.NET DataTable, called dtChartData:

               Login Failure  Login Success
-------------- -------------- -------------
2013-03-27     1              69
2013-03-26     0              32
2013-03-25     1              86
2013-03-22     0              11

It holds data for number of successful/unsucessful logins for a given date. We want to display this data as a Bubble chart with dates displayed on X-Axis. Continue reading →

Speed up UltraWebGrid rendering on rebind

If you’re using Infragistics UltraWebGrid with it’s property Browser="Xml", you may find yourself living in a shotgun shack in a strange situation: When grid is rebinding – it takes (comparatively) short time to do server-side processing and then a very long time to render grid in the browser.

In my case it was most felt when grid (which had ViewType="OutlookGroupBy") was initially grouped with a lot of data in each group and then ungrouped back into flat view when user dragged last group column out. Using IE9 built-in developer tools I ran JavaScript profiler I found that culprit was Infragistics JS function “disposeNode” which was called numerous times and had worst both inclusive and exclusive execution time. Continue reading →

Remove namespaces from Xpath expression

If you ever need to remove namespaces from an XPath string, regex is a way to go. [\w]+:(?!:) expression to be precise. So if, for example your xpath is

Dim sXpath as String = "/ns1:ElementOne/ElementTwo/ns2:ElementThree"

this code

Regex.Replace(sXpath, "[\w]+:(?!:)", "")

will convert it into

/ElementOne/ElementTwo/ElementThree

Thanks Bogdan Emil Mariesan @ Stack Overflow for the solution

Opening SpreadsheetML 2003 in Excel 2010

If you’re trying to open an Excel 2003 XML file (SpreadsheetML) in Excel 2010 and getting “The file is corrupt and cannot be opened” error, try opening that file in WordPad (it will open as text XML) and save it back. Now try opening it in Excel 2010 again. You will still get “The file you’re trying to open is in a different format than specified by the file extension” warning, but after that the file should open.

The value of the method attribute may not be html. Solution for the error.

If you get the following error while browsing a page in Internet Explorer:

The value of the ‘method’ attribute may not be ‘html’

chances are MSXML registration is corrupted on your machine. To fix this, open DOS prompt and type following commands:

regsvr32 msxml.dll
regsvr32 msxml2.dll
regsvr32 msxml3.dll

This will re-register MSXML and the error will go away.