You are developing a Windows Forms application at XYZ Inc. that must provide context-sensitive online help. When the user presses F1, a pop-up help window should display descriptive text for whichever TextBox currently has focus. You are using the HelpProvider control. Which HelpProvider method should you call to associate a specific help text string with a given TextBox control?

Introduction / Context:
Windows Forms applications often need to provide user assistance directly in the interface, especially when users press the F1 key. The HelpProvider component is designed to connect controls to help content in a flexible way. This question focuses on the specific HelpProvider method you should call to attach a simple text string that appears in a small pop-up window when help is requested for a particular control, such as a TextBox.

Given Data / Assumptions:

• You are using a Windows Forms application created in Visual Studio.
• The application uses the HelpProvider control placed on the form.
• Users can press F1 to request help for the control that currently has focus.
• The help content is a short text string that should be shown in a pop-up window.
• You want to call a HelpProvider method and pass both the TextBox control and the help text.

Concept / Approach:
The HelpProvider class exposes several methods that associate different kinds of help with a control. SetShowHelp indicates whether a control has help at all. SetHelpKeyword links a control to a keyword in an external help file. SetHelpNavigator identifies how that keyword is used. SetHelpString is specifically meant to attach a simple text string that the HelpProvider displays in a pop-up window when the user requests help. Therefore, to show a small text window for the currently focused TextBox when F1 is pressed, you must call SetHelpString with the control and the desired help text.

Step-by-Step Solution:
1. Place a HelpProvider component on your Windows Form from the toolbox. 2. On the form, add a TextBox control that requires context-sensitive help. 3. In code or through the designer, ensure that the HelpProvider is associated with the form and controls. 4. Call helpProvider1.SetHelpString(textBox1, "Enter the product code exactly as printed on the label."); to associate the help text. 5. Optionally call helpProvider1.SetShowHelp(textBox1, true); so that the control is recognized as having help available.

Verification / Alternative check:
After implementing SetHelpString, run the application. Click inside the TextBox to give it focus and press F1. A small help window should appear, displaying the string you passed to SetHelpString. If you set SetShowHelp to true and configured your HelpProvider on the form, the help text should consistently appear whenever the control is focused and the user requests help.

Why Other Options Are Wrong:
Option A, SetShowHelp, only specifies that a given control has associated help; it does not define what help text or content to show. Option C, SetHelpKeyword, is used when you rely on an external help file and want to map a keyword to a particular entry or topic. Option D, ToString, is merely the standard method inherited from System.Object, and it is not related to the HelpProvider functionality. None of these alternatives directly attach an inline help text string to a control for F1 pop-up help.

Common Pitfalls:
A frequent mistake is to confuse keyword-based help (which uses SetHelpKeyword and an external help file) with inline help strings (which use SetHelpString). Another pitfall is forgetting to call SetShowHelp, which might prevent the help system from recognizing that help is available for the control. Developers may also accidentally attempt to show help by overriding key events manually instead of leveraging the built-in HelpProvider support. Understanding the intended role of each HelpProvider method makes implementing user assistance much easier.

Final Answer:
You should call the HelpProvider.SetHelpString method to associate a descriptive help text string with a specific TextBox so that the text is shown in a pop-up window when F1 is pressed.