Sams Teach Yourself C# in 24 Hours

By James Foxall and Wendy Haro-Chun

• Table of Contents
  • Copyright
  • About the Authors
  • Acknowledgments
  • Tell Us What You Think!
  • Introduction
  • Audience and Organization
  • Conventions Used in This Book
  • Onward and Upward!
  • Part I. The Visual Studio Environment
  • Hour 1. A C# Programming Tour
  • Hour 2. Navigating C#
  • Hour 3. Understanding Objects and Collections
  • Hour 4. Understanding Events
  • Part II. Building a User Interface
  • Hour 5. Building FormsPart I
  • Hour 6. Building FormsPart II
  • Hour 7. Working with the Traditional Controls
  • Hour 8. Advanced Controls
  • Hour 9. Adding Menus and Toolbars to Forms
  • Hour 10. Drawing and Printing
  • Part III. Making Things HappenProgramming!
  • Hour 11. Creating and Calling Methods
  • Hour 12. Using Constants, Data Types, Variables, and Arrays
  • Hour 13. Performing Arithmetic, String Manipulation, and Date/Time Adjustments
  • Hour 14. Making Decisions in C# Code
  • Hour 15. Looping for Efficiency
  • Hour 16. Debugging Your Code
  • Hour 17. Designing Objects Using Classes
  • Hour 18. Interacting with Users
    • Displaying Messages Using the MessageBox.Show() Method
    • Creating Custom Dialog Boxes
    • Interacting with the Keyboard
    • Using the Common Mouse Events
    • Summary
    • Q&A
    • Workshop
  • Part IV. Working with Data
  • Hour 19. Performing File Operations
  • Hour 20. Controlling Other Applications Using Automation
  • Hour 21. Working with a Database
  • Part V. Deploying Solutions and Beyond
  • Hour 22. Deploying a Solution
  • Hour 23. Introduction to Web Development
  • Hour 24. The 10,000-Foot View
  • Appendix A. Answers to Quizzes/Exercises

Creating Custom Dialog Boxes

Most of the time, the MessageBox.Show() method should be a sufficient means to display messages to a user. At times, however, the MessageBox.Show() method is too limited for a given purpose. For example, suppose you wanted to display a lot of text and therefore wanted a message box that was sizable by the user.

Custom dialog boxes are nothing more than standard modal forms with one notable exception: one or more buttons are designated to return a dialog result, the same as the buttons on a message box shown with the MessageBox.Show() method.

You're now going to create a custom dialog box. Create a new Windows Application titled Custom Dialog Example. Change the name of the default form to fclsMain, set its Text property to Custom Dialog Box Example, and set the Main() entry point of the project to reference fclsMain rather than Form1. Add a new button to the form and set its properties as follows:

Next, you're going to create the custom dialog box. Add a new form to the project by choosing Add Windows Form from the Project menu. Save the new form with the name fclsCustomDialogBox.cs. Change the Text property of the new form to This is a custom dialog box. Add a new text box to the form and set its properties as follows:

For a custom dialog box to return a result like a standard message box does, it must have buttons that are designated to return a dialog result. This is accomplished by setting the DialogResult property of a button (see Figure 18.6).

Figure 18.6 The DialogResult property determines the return value of the button.

Add a new button to the form and set its properties as shown in the following table. This button will act as the custom dialog box's Cancel button.

Last, you need to create an OK button for the custom dialog box. Create another button and set its properties as shown in the following table:

Specifying a dialog result for one or more buttons is the first step in making a form a custom dialog box. The second part of the process is in how the form is shown. As you learned in Hour 5, "Building Forms—Part I," forms are displayed by calling the Show method of the form or setting its visible property to true. However, to show a form as a custom dialog box, you call the ShowDialog method instead. When a form is displayed using ShowDialog, the following occurs:

• The form is shown modally.
• If the user clicks a button that has its DialogResult property set to return a value, the form is immediately closed and that value is returned as the result of the ShowDialog method call.

Notice how you don't have to write code to close the form; clicking a button with a dialog result closes the form automatically. This simplifies the process of creating custom dialog boxes. Return to the first form in the form designer by clicking the Form1.cs [Design] tab.

Double-click the button you created and add the following code:

fclsCustomDialogBox  objCustomDialogBox = new fclsCustomDialogBox();

if (objCustomDialogBox.ShowDialog() == DialogResult.OK)
    MessageBox.Show("You clicked OK.");
else
    MessageBox.Show("You clicked Cancel.");

objCustomDialogBox = null;

Press F5 to run the project, click the button to display your custom dialog box (see Figure 18.7), and then click one of the available dialog box buttons. When you're satisfied the project is working correctly, stop the project and save your work.

Figure 18.7 The ShowDialog method enables you to create custom message boxes.

The capability to create custom dialog boxes is a powerful feature. Usually, a call to MessageBox.Show() will suffice, but when you need more control over the appearance and contents of a message box, creating a custom dialog box is the way to go.

Share This