Using Buttons

There are two common reasons for using a button control within a KineticaRT based application:

1. To set the value of a channel.
2. To execute an action using an Event Handler.

In the second case it is normally best to also set the value of a channel and use the change of value of the channel to trigger the Event Handler since this:

1. Allows the same action to be triggered from several control screens/tabs/windows under the control of a single control sequence or event handler. This removes the need to replicate code and faults while making it easy to place duplicate controls in convenient places for the user.
2. Allows the same action to be triggered from several computers under the control of a single control sequence or event handler. This gives protection from several operators trying to control one system simultaneously.
3. Allows the control sequences to continue executing correctly even if the user interface is not running, has been closed or has several instances running simultaneously.
4. Allows code to be located centrally rather than scattered throughout the user interface files.
5. Allows end users to copy sections of the user interface without having to copy the code which implements them and provide synchronization.

See Event Handlers for information on implementing an event handler.

In some circumstances it may be necessary to place code within a window/tab, normally because of a requirement to set individual properties on a control, call methods on a control or handle an interaction between several controls on the same window. This is generally a programming task for a developer rather than an end user. There are two ways to handle it:

1. Use Visual Studio to write a new User Control containing the required control(s) and the required code. End users can then drop the new control onto the windows without having to worry about programming issues.
2. Add code to the window. Controls within windows/tabs/frames are stored in panel files. These are executable dll files. When a panel file is saved, C# code is generated and compiled into the executable dll. User code can be added to these panel files in the same way that code can be added to a new (wizard generated) control within Visual studio.
   Note: At the moment, C# source files “.cs” files are generated when the panel is saved, these may be modified but will be overwritten if the panel file is saved again. If they are modified then the .dll file should be deleted, this will cause a recompilation when next loaded.