DialogResult Enumeration in Java

Scanner Data Matrix ECC200 in Java DialogResult Enumeration

The Show method returns a value that represents the button that the application user clicked in the message box Each button is represented by a member of the DialogResult enumeration listed in Table 10-5

Member Name Abort Cancel Ignore No None OK Retry Yes Description The dialog box s return value is Abort, usually sent from a button labeled Abort The dialog box s return value is Cancel, usually sent from a button labeled Cancel The dialog box s return value is Ignore, usually sent from a button labeled Ignore The dialog box s return value is No, usually sent from a button labeled No Nothing is returned from the dialog box This means that the modal dialog box continues running The dialog box s return value is OK, usually sent from a button labeled OK The dialog box s return value is Retry, usually sent from a button labeled Retry The dialog box s return value is Yes, usually sent from a button labeled Yes

The DialogResult enumeration corresponds to the buttons in the MessageBoxButtons enumeration listed previously in Table 10-2, and will be returned if the corresponding button is chosen Thus, if the application user chooses the Yes button, the Show method returns the value DialogResultYes The return value usually is stored in a variable for later use in the application The data type of that return value should be the same as the data type returned by the function or method Accordingly, you often use the DialogResult data type for the variable in which you will save the return value of the Show method You may declare that variable as follows:

Once you have declared the variable, the next step is to use it to store the return value of the Show method The variable drQuit should be on the left side of the assignment operator, so it will receive the return value of the Show method that is called on the right side of the assignment operator:

drQuit = MessageBoxShow("Do you really want to quit ", _ "Exit Confirmation", _ MessageBoxButtonsYesNo, _ MessageBoxIconWarning, _ MessageBoxDefaultButtonButton2)

When this code statement executes, and the application user clicks a button in the message box, closing the message box, the value of the variable drQuit will be either DialogResultYes or DialogResultNo, depending on whether the application user clicked the Yes or No button

The form object has a Close method that, as its name indicates, closes the form Because this is the only form in the project (other than the message box, which will close when the user clicks the Yes or No button), closing the form ends the application as well However, we only want to close the form if the application user clicks Yes, not if the application user clicks No The following code closes the form if, and only if, the application user s choice was Yes:

This code statement first compares the value of drQuit and DialogResultYes using the If keyword If the user chose Yes, the value of drQuit is DialogResultYes,

so the comparison drQuit = DialogResultYes will be True and the MeClose() statement is executed However, if the user chose No, the value of drQuit is DialogResultNo, so the comparison drQuit = DialogResultYes will be False and the MeClose() statement will not be executed

Although the message box is a valuable tool, it is limited in that it only can contain a text prompt, buttons, an icon, and a title Further, the only information a message box can obtain from the application user is which button the user clicked The message box does not permit the application user to enter text in a text box, choose an item from a drop-down list, select a check box or radio button, and so on If you need a user interface richer than the message box, you may create a custom and more complex version of a message box the dialog form