Easy way to get your XML into a DataTable

Now I might just be blind, or incredibly incapable at searching google or reading my LINQ books (very possible) but I hadn't found a simple way to get a 2-level XML document into a DataTable for use in a GridView or just simple DataTable manipulation utilizing LINQ (I assume this is because DTs are 2 dimensional, and XML files can be all sorts of mash-ups of information). Since LINQ is so powerful, I assumed it wouldn't be all that difficult, turns out I was right, it's pretty easy. Here is the code:


This is completely dynamic, so it doesn't matter what or how many elements you have. It does rely on the first element to set the DataTable columns, so make sure that one is complete. Though the XML does have to be limited to 2-dimensional elements; in fact, I am not even sure what happens if you feed the function bad data? The XML should resemble this structure:

<?xml version="1.0" encoding="utf-8"?>
<root>
      <person>
            <age>26</age> 
            <name>stan</name> 
            <hobbies>partying</hobbies> 
      </person>
      <person>
            <age>26</age> 
            <name>matt</name> 
            <hobbies>taking dumps</hobbies> 
      </person>
</root>

In that structure, each person will be a row, and age, name and hobbies will the the columns in the datatable:

age	name	hobbies
26	stan	partying
26	matt	taking dumps

Call it like this:


And that's it, you have your DataTable.

A simple alternative method to the Ajax Control Toolkit's

Don't get me wrong, the Ajax Control Toolkit (ACT) is great, but a couple of the controls leave something to be desired.  For one, the things required to integrate the cascading dropdowns is a bit excessive IMO.  No need ot require asmx files to do a simple lookup.  Also, if you are changing values in your dropdowns (as I needed to do), this gives you no simple way to do it.

 

Figuring that dropdowns are almost always relatively small collections of choices, and I would be editing them often for my purposes, an XML files seems to be the perfect fit for this situation.  On top of that, with the ease of LINQ, this would be extremely easy to make an interface for editing the properties so my users could edit them without knowing the first thing about XML. 

 

I am going to try to basically copy the ACT in terms of functionality as I really like it, but change it 'under the hood'.  First thing is to make a simple XML file with my options in it, I used old cars for an example:

<?xml version="1.0" encoding="utf-8" ?>
<dropdowns>
    <makes>
        <maker>-please select-</maker>
        <maker>Ford</maker>
        <maker>Chevy</maker>
        <maker>Dodge</maker>
    </makes>
    <cars>
        <car_maker name="Ford">
            <car>Bronco</car>
            <car>Galaxy</car>
            <car>Mustang</car>
        </car_maker>
        <car_maker name="Chevy">
            <car>Chevelle</car>
            <car>Corvette</car>
            <car>Nova</car>
        </car_maker>
        <car_maker name="Dodge">
            <car>Charger</car>
            <car>Ram</car>
        </car_maker>
    </cars>
</dropdowns>

 Now add the Dropdowns to yoru .aspx with a few more properies added (required for this to work) the properties are:

1. cascadeTo : The dropDown you want to cascade to
2. cascadeCategory : The category in XML your cascade properties lie
3. cascadeDescendant : The final level in XML where your items lie
4. cascadeBlank : [optional] What the cascading DropDown will display when it is awaiting a selection

Here is my .aspx, Notice I added "- Select Make -" to the ddlModel DropDownList as that will help give the user some guidance and it is the same as the 'cascadeBlank' I designated:

Make:<br />
<asp:DropDownList ID="ddlMake"  runat="server" cascadeTo="ddlModel" cascadeCategory="car_maker" cascadeDescendant="car" cascadeBlank="- Select Make -"  AutoPostBack="true" onselectedindexchanged="ddlMake_SelectedIndexChanged" />
<br /><br />
Model:<br />
<asp:DropDownList ID="ddlModel" runat="server" Enabled="false"  >
    <asp:ListItem>- Select Make -</asp:ListItem>
</asp:DropDownList>

Next, you need to access your XML document and fill your initial menu, so make sure to add something like this to your code-behind:

XElement x;
protected void Page_Load(object sender, EventArgs e)
{
    x = XElement.Load(Server.MapPath(".") + "\\App_Data\\dropdowns.xml");
    if (!IsPostBack)
        foreach (XElement elem in x.Descendants("maker")) addDdlItems(ddlMake, elem.Value);
}

public void addDdlItems(DropDownList ddl, string value)
{
    ListItem li = new ListItem();
    li.Value = value;
    ddl.Items.Add(li);
}

Now you simply need to call cascade.fromThisDropDown from your _SelectedIndexChange event.  This way you don't need to write any code, just place the cascade.cs fil into your App_Code folder:

protected void ddlMake_SelectedIndexChanged(object sender, EventArgs e)
 { cascade.fromThisDropDown(this.Page, (DropDownList)sender, x); }

And that's it.  You can place it inside an UpdatePanel for the same exact Ajax effect that you have with the ACT, but without those pesky asmx files. If you want to see the cascade.cs code, click here to view/hide.

 

Not completely dummy proof, but I think it's useful.  You can download just the cascade class, or the full working example:

 

Simple fixes to simple errors when just starting out with open social widgets 

Just made my first basic open social gadget for Daily Atheist Quote and ran into an error which I couldn't find any documentation (I didn't really look all that hard).  Basically I tried to publish my first widget from the Google Scratchpad and I got this warning:

Please consider fixing the following issues below before publishing your gadget:

    * Author attribute is missing or undefined.
    * Author email attribute is invalid or undefined.
    * Height attribute must be defined.
    * Width attribute must be defined.
    * Description attribute is missing or undefined.
    * Thumbnail attribute must be defined and set to a valid image URL.

Couldn't figure out where this stuff actually went.  Turns out after messing around, it really was very simple and I just had to stick that info into the ModulePrefs:

 

 

And that is it, your Widget should now validate through the Scratchpad Publishing just fine.