A dishwasher is made up of many parts. You can find the model number of your dishwasher and enter it into an appliance parts website. From there, you should be presented with a breakdown of parts for your particular dishwasher. Or, just search for appliance parts and from there you can see all the different parts that a website sells.
A person can purchase dishwasher parts from Lowes, Sears and Home Depot. If you know the brand of the dishwasher it may be easier to contact the maker as they will also provide parts for sale.
http://www.partselect.com is a great online website hat allows you to choose your brand and model of dishwasher and then find parts to fix it. These parts do include dishwasher racks.
There are a number of online stores that sell replacement Frigidaire dishwasher parts. These include the official Frigidaire website, Repair Clinic, Sears Parts Direct and Appliance Parts Pros.
For most brands none of the parts are dishwasher safe.
You can go on Whirlpool's website to order specific dishwasher part from your type of dishwasher. You can also go on a website named, "Amazon", and order you parts for your, Whirlpool, dishwasher. Those are to main way to order your parts for your Whirlpool dishwasher.
You can buy parts at the GE Appliance store online at: http://www.geappliances.com/. They also offer instructions on how to install parts.
At your local appliance parts store, or online.
Possibly at your local appliance parts store, or online.
Try an appliance parts website. Usually they have schematics and a breakdown of parts for appliances.
One can purchase Kenmore dishwasher parts online at Searspartsdirect or Repairclinic websites. Canadians can purchase Kenmore dishwasher parts also online at Partselect Canadian website.
At your local appliance parts store, or online.