Question

Situation: I am making a Collapsible Panel. In my business situation, I am required to have the panel support the following:

• A “direction” (ie, will it dock top, bottom, left, or right). This changes which direction it collapses and a few other things.

• A “style”. There are some predefined visual styles for this product (defining background color, gradient or not, text color, hover color, etc).

Here’s the problem: certain styles are incompatible with certain directions. Here are the requirements:

• There needs to be some way to prevent/warn the programmer if he/she coded the panel to have incompatible style and direction. For example, having the panel throw a runtime exception if they are incompatible will satisfy this requirement.

• Not allow anyone to dynamically change either style or direction during runtime. If I need to, then I can allow it to be “dynamically” changed in InitializeComponent, but not anywhere else.

• The panel needs to be visible in Design View. but not necessarily able to be dragged and dropped in design view, and technically I don’t need to even alter the attributes of the panel in design view. Though I obviously want either of those other things if possible.

One potential solution: Have the constructor take two inputs: a direction and a style. That way both the changes are treated as an atomic action. If they are not both changed at the same time, then between changing the direction/style and then changing the other, the panel will be in an inconsistent state. I want to avoid that.

How can I get the Design View to not use the default constructor and/or what are better practices for fulfilling the requirements?

Note

The Panel is only an example and a use case to ask the broader question. I want this post to answer the direct question on the best practices for getting the Design View to handle my requirements. If the Visual Studio supports injecting a non-default constructor in InitializeComponent, then I want to know how (and any caveats with that). If there are better practices which fulfill the listed requirements, then I would like to know that as well.

Answer 1

Add support for the ISupportInitialize interface which the designer can use to set all the properties and tell you when it’s finsihed.