Grouping Radio Buttons on a Dialog Box
When you add radio buttons to a dialog box, treat them as a group by setting a Group property in the Properties window for the first button in the group. A control ID for that radio button then appears in the Add Member Variable Wizard, allowing you to add a member variable for the group of radio buttons.
You can have more than one group of radio buttons on a dialog box, and each group should be added using the following procedure.
To add a group of radio buttons to a dialog box
Select the radio button control in the Toolbox Window and click the location in the dialog box where you want to place the control.
Repeat Step 1 to add as many radio buttons as you need. Make sure that the radio buttons in the group are consecutive in the tab order (for more information, see Changing the Tab Order of Controls).
In the Properties Window, set the Group property of the first radio button in the tab order to True.
Changing the Group property to True adds the style to the button's entry in the dialog object of the resource script and ensures that a user can only select one radio button at a time in the button group (when the user clicks one radio button, the others in the group are cleared). WS_GROUP
Only the first radio button in the group should have the Group property set to True. If you have additional controls that are not part of the button group, set the Group property of the first control that is outside the group to True as well. You can quickly identify the first control outside of the group by pressing CTRL+D to view the tab order.
To add a member variable for the radio button group
Right-click the first radio button control in the tab order (the dominant control and the one with the Group property set to True).
Choose Add Variable from the shortcut menu.
In the Add Member Variable wizard, select the Control variable check box, then select the Value radio button.
In the Variable name box, type a name for the new member variable.
In the Variable type list box, select int or type int.
You can now modify your code to specify which radio button should appear selected. For example, m_radioBox1 = 0; selects the first radio button in the group.
For information on adding resources to managed projects, please see Resources in Applications in the .NET Framework Developer's Guide. For information on manually adding resource files to managed projects, accessing resources, displaying static resources, and assigning resources strings to properties, see Walkthrough: Localizing Windows Forms and Walkthrough: Using Resources for Localization with ASP.NET.