Best way to play with Form Designer

Question

Hello I am working with windows form since a few days but having some question about the good way to play with the windows form designer. If I use external class with object data list and I want to use use them with a ComboBox for example: this.comboBox1.FormattingEnabled = true; /*this.comboBox1.Items.AddRange(new object[] { 01 02 03 }); * */ Data myData = new Data(); this.comboBox1.Items.AddRange(myData.m_data); then If I add modification to the form with the Designer all my added code is reset. Does that mean that If I insert code to the Windows Form Designer generated code I can't no more use the Designer ? or is there any secret tricks ? or is it better to not use the designer ? thanks for you help.

Vulpes · Answer

'Out of kilter' means that the actual code and what the designer thinks the code should be will no longer correspond with each other which is not a nice situation to be in. Basically you should just use the designer to place controls on the form set their properties and open up 'skeleton' eventhandlers for their events. The best place to add items to your combobox is in the Form_Load eventhandler which fires before the form shows for the first time. Just double clicking anywhere on the form in the designer will bring up a skeleton handler for this event to which you can add your code.

raf · Answer

OK. thanks for your good advices Sam!

Sam Hobbs · Answer

It depends on what you need to do to the control; if it were me I would probably set the FormattingEnabled property in the form's constructor just after the InitializeComponent() method is called. I agree that putting data in the control is appropriately done in the form load event. Note that C# has partial class definitions just so you can do that. The InitializeComponent() method is created in the designer.cs file which is generated by the designer in VS but the other file has the other portion of the class for you to modify as needed. It is designed so you don't need to modify the designer.cs file. There is however a secret trick that object-oriented programmers use but the designers (programmers) of the C# IDE have hidden from C# beginners. You can derive a class from a control. That technique is probably not appropiate for this situation but it can be very useful in many situations.

raf · Answer

ok got you! Thanks !

raf · Answer

hello vulpes thanks for your reply. Actually I well understood that it is not recommanded to edit the generated code by designer and also not recommanded to write manually all code for my windows form application. So it seems that there is a third alternative but I don't really understand how to process. Does 'out of kilter mean that I have to write two codes at the same time? a kind of template code generated with the designer and then I have to copy the template to my current/real code ?

Vulpes · Answer

It's better not to alter the code generated by the designer manually. In particular avoid editing the InitializeComponent() method which contains the basic design for the form. If you do then as soon as you make a change to the form from the designer it is likely that your changes will be overwritten. You might even end up with an application where the designer and the actual code become 'out of kilter' with each other. Whilst it's possible to write all the code for a windows forms application manually this isn't a practical proposition for applications of any size.