Code Nuggets: A Side-effect of Using DropDownList AppendDataBoundItems With Databound Items

Picture this: You have a webform with two DropDownLists, both of them are databound to some data you get from a database. Now the first DropDownList’s selection determines the contents of the second dropdown. So you simply do a AutoPostBack = true for the first dropdown and populate the second dropdown in the handler function. Right?

But wait. What if you are required to put in a static item in the dropdown? Something like “– Please Select –“ as the first item in the list to force the user to make a conscious choice. Hmmm, so you look around and find the nice little property named AppendDataBoundItems that will take care of that. All you have to do is declare the first (static) item in the Items collection in the designer (or put a <asp:ListItem> tag inside your <asp:DropDownList> tags) and set AppendDataBoundItems to true. This nice little property tells the DropDownList to add the databound items after the statically declared items, so you can have your happy little “– Please Select –” in your dropdown.

The Side-effect:

The side-effect becomes evident when you play around with your two dropdowns. Its immediately clear that something is not quite right. The AppendDataBoundItems property forces your dropdown’s items from the previous postback to be treated as static objects onthis display. Sort of where you get an ever-growing second dropdown with a hangover from the postback, which is clearly not what you wanted in the first place!

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Code Nuggets: Getting two SQL column values in a single column

Well this type of thing doesn’t come up very frequently (at least to me) and if you’re like me working on multiple databases it gets very frustrating when it does come up. Since I don’t use it very frequently, I tend to forget how to do it properly in the database system I am using at the time.

So it goes something like this: Suppose you have a simple SQL table called Users. Now this table has three columns, id (int), firstName (varchar) and lastName (varchar)…

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java.CompilerError when running RMIC

The other day I was trying out a Java RMI program in connection to an assignment. Let me be very clear here: I really like Java as it was one of my first proper programming languages (mind you, I am talking here circa 1999-2000 when Java-fever hadn’t caught up) and I am a big fan of its elegance. The only turn-off which made me head towards Microsoft’s direction was the lack of a proper, Visual Studio-league IDE for Java in those days. Much water has passed under the bridge, and there are many better IDEs for Java now, like Eclipse and NetBeans, but the curse still remains. (You might also want to give JCreator a shot, one of my favorite Java editing tools).

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