Well, to be fair, it wasn't really "a challenge", just one of those pain in the ass-spaghetti-stinky piece of code that sometimes we have to write to go on with our lives.
I hated the idea to have some ugly loop (since I discovered linq, all loops are ugly!) that iterated 30 times and grabbed the current date the chart was accessed and then subtracted the index of the loop, and finally made sure that the result was sorted ascending.
So Range function and LinqToXml came to the rescue! Actually, I didn't know that Range() was available in .Net. A co-worker pointed out to me that I did exist and that it was under the "Enumerable" Class. (Thanks Connor!)
So, the potentially "ugly" loop ended up being a beautiful one-liner linq query:
Dim category = (From index In Enumerable.Range(0, 30) Select _
<category label=<%= DateTime.Now.AddDays(-index).ToString("M/dd") %>/>).Reverse
Man, Linq rocks! I can't stop saying it. Well now that I had the hard part done, I had left to generate some empty data sets and then put it all together:
Dim emptySets = From index In Enumerable.Range(0, 30) Select <set value="0"/>
'Build the Xml template
Dim chartData = <?xml version="1.0" encoding="utf-8"?>
<chart>
<categories>
<%= category %>
</categories>
<dataset SeriesName="Name1">
<%= emptySets %>
</dataset>
</chart>
'return the build template to the calling function
Return chartData.ToString
So the ouput of my query would look like this:
<chart>
<categories>
<category label="6/26"/>
<category label="6/27"/>
<category label="6/28"/>
<category label="6/29"/>
<category label="6/30"/>
<category label="7/01"/>
<category label="7/02"/>
<category label="7/03"/>
<category label="7/04"/>
<category label="7/05"/>
<category label="7/06"/>
<category label="7/07"/>
<category label="7/08"/>
<category label="7/09"/>
<category label="7/10"/>
<category label="7/11"/>
<category label="7/12"/>
<category label="7/13"/>
<category label="7/14"/>
<category label="7/15"/>
<category label="7/16"/>
<category label="7/17"/>
<category label="7/18"/>
<category label="7/19"/>
<category label="7/20"/>
<category label="7/21"/>
<category label="7/22"/>
<category label="7/23"/>
<category label="7/24"/>
<category label="7/25"/>
</categories>
<dataset SeriesName="Name1">
<set value="0"/>
<set value="0"/>
<set value="0"/>
<set value="0"/>
<set value="0"/>
<set value="0"/>
<set value="0"/>
<set value="0"/>
<set value="0"/>
<set value="0"/>
<set value="0"/>
<set value="0"/>
<set value="0"/>
<set value="0"/>
<set value="0"/>
<set value="0"/>
<set value="0"/>
<set value="0"/>
<set value="0"/>
<set value="0"/>
<set value="0"/>
<set value="0"/>
<set value="0"/>
<set value="0"/>
<set value="0"/>
<set value="0"/>
<set value="0"/>
<set value="0"/>
<set value="0"/>
<set value="0"/>
</dataset>
</chart>
So, there it is. no messy loops, no smelly code, just ....Linq.
Hope this helps
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