Rory Hansen

I’m just beginning to transition to ASP.NET and C# from a largely Java / C++ / C background, and along the way, I’m finding myself often stumped with what seems like really simple problems.

For example, today, when writing a ASP.NET web service in C#, I had trouble casting a money value retrieved from a MS SQL database to a double. The following code would always report an error:

C#
double cost;
cost = (double) dr["cost"];

I also tried using a float, but that didn’t fix the problem either.

The _correct_ type to use in this case is actually Decimal, and I learned this only after a co-worker sent me a link to a document on the MSDN site that has a table showing all of the proper type conversions from one system to another. So, this code _does_ work:

C#
Decimal cost;
cost = (Decimal) dr["cost"];

You can find the table here:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpguide/html/cpconusingparameterswithdataadapters.asp

(Scroll about halfway down; you can’t miss it.)