Getting ready

Many VCL controls are able to delegate their drawing, or part of it, to user code. It means that we can use simple event handlers to draw standard components in different ways. It is not always simple, but TDBGrid is customizable in a really easy way. Let's say that we have a class of musicians that have to pass a set of exams. We want to show the percent of exams already passed with a progress bar and if the percent age is higher than 50, there should also be a check mark in another column. Moreover, after listening to the pieces played at the exams, each musician received votes from an external examination committee. The last column needs to show the mean of votes from this committee as a rating from zero to five.