COMSOL 6.3 - Button and Item

Clicking on a , ribbon, menu, or toolbar is an event that triggers an action defined by its command sequence. The main section of the window for a button or item allows you to:

The settings for a ribbon button, defined as in a , are very similar to those of a button form object. However, in their respective settings windows, the sections and settings for , , and are available only for the button form object. Similarly, the settings windows for menu and toolbar items are also closely aligned with those of a button form object.

The section lets you control the action associated with a button-click event. The figure below shows the window for a button that triggers a sequence of four commands.

A menu, ribbon, or toolbar item will also provide a section in its window, and the functionality described in this section applies. For more information on using menu, ribbon, and toolbar items, see Graphics Toolbar, The Main Window Editor, Table, and Toolbar and Form Toolbar.

To define a sequence of commands, in the section, select a node in the editor tree. Then click one of the highlighted buttons under the tree. Alternatively, right-click in the tree and select the command or double-click. In the figure below, the node is selected and the available commands and are highlighted. Click to add a geometry-building command to the command sequence. Click to add a command that first builds and then plots the geometry. The option will take you to the corresponding node in the model tree or the application tree.

You do not need to precede a command with a command (that you get by clicking ). The command will first build and then plot the geometry. In a similar way, the command will first build and then plot the mesh.

The command icons highlighted for selection are those applicable to the particular tree node. This is a list of the command icons that may be available, depending upon the node:

Some commands, such as the various plot commands, require an argument. The argument to a plot command, for example, defines which of the different graphics objects the plot should be rendered in.

The example below shows the window and command sequence for a button as created by the Form Wizard. This button has a command sequence with two commands: and .

The command has one argument, form1/graphics1.

To add or edit an input argument, click the button below the command sequence, as shown in the figure below.

To reference graphics objects in a specific form, the following syntax is used: form1/graphics2, form3/graphics1, and so on. If a specific form is not specified, for example, graphics1, then the form where the button is located is used.

To control the order and contents of the sequence of commands, use the , , and buttons located below the command sequence table.

A sequence of commands can be automatically converted to a new method, and further edited in the Method Editor, by clicking .

Open the new method by clicking .

You can also create a method that is local to a form or form object by clicking or , respectively.

The method contains calls to built-in methods corresponding to the commands in the commend sequence, as shown in the figure below.

In this example, the first line:

runs corresponding to the model tree node containing the first study with tag std1 (the first study node is called unless changed by the user). The second and third lines:

use the built-in method useGraphics to display plots corresponding to plot groups pg3 and pg1, respectively. In this example, the plots are displayed in two different graphics objects, graphics1 and graphics2, respectively.

For more information on methods, see The Method Editor.

The command allows you to set values of parameters and variables that are available in the , , and nodes. In addition, can be used to set the values of properties made accessible by (see Data Access in the Form Editor). The figure below shows a command sequence used to initialize a set of model parameters and a string variable.

To learn how to perform the same sequence of operations from a method, select under the command table.

A button on a form can also be used to display a new form. This can be done in two ways. The first is to use the command, which will replace the original form with the new form. The second is to use the command. In this case, the new form will pop up as a dialog over the current form, and will usually request input from the user.

In the section , you can select the command. The figure below shows the command sequence for a button with a command .

This command will leave the form associated with the button and make the specified form visible to the user.

In order to use the command, begin with the section and select the form that you would like to show. The figure below shows an example of the settings for a button with the command .

With these settings, clicking the button in the application will launch the following dialog corresponding to :

The window in this example contains a text label object and an button, as shown in the figure below.

In the window, the section has two checkboxes:

In the example above, the checkbox is selected, ensuring that the window closes when the button is clicked. Since has no user inputs, the checkbox does not have any effect.

Typical dialog buttons and their associated dialog actions are:

Button	Dialog Actions
OK	Close dialog and Store changes
Cancel	Close dialog
Apply	Store changes

A dialog blocks any other user interaction with the application until it is closed.

In order to control when data entered in a dialog is stored, there is a list in the section of the window of a form where you can select whether to store data or when the change occurs, as shown in the figure below.

When the option is selected, the variables that have been changed by the user in the dialog will not be updated until the OK button (or similar) in the dialog has been clicked. This requires that the checkbox is selected, in the window of the OK button. When the option is selected, variables changed by the user in the dialog is updated immediately including while the dialog is still open.

When is cleared, the form will never get any vertical scrollbar. Instead, the scrollbar will appear on the form objects inside the form, if possible. To obtain a satisfactory result, the form has to be created in grid mode. The form object which should get the scrollbar must be in a row with setting and its alignment set to .

In the window for a button, the section contains font settings as well as settings that control the state of the button object.

Whether or not the button object should be or is controlled from the checkboxes under the subsection. The section for most form objects has similar settings, but some have additional options; for example, input field objects.

A button, or another form object, with the checkbox cleared will not be shown in the user interface of the running application. A form object with the checkbox cleared will be disabled, or “grayed out”, but still visible. The state of a form object can also be controlled using built-in methods. For example, assume that a Boolean variable enabled is used to determine the enabled/disabled state of a button with button3. In this case, you can control the state of the button as follows:

In a similar way, the call

lets a Boolean variable visible control whether the button is shown to the user or not.

For more information, see GUI-Related Methods and the Application Programming Guide.