After creating a report and formatting it to your satisfaction, the report needs to be integrated into the application. There are many ways to do this which makes chapter 3 one of the more complicated to understand, and yet one of the most important in the book. Understanding the best way to integrate reports into your application is essential for designing the best reporting solution.
There are a lot of different ways to integrate a report into an application, and some of the ways can be combined together. The different combinations create an interesting matrix of possibilities for you to choose from. If this is your first experience to writing reports with .NET, it may seem a little overwhelming. To try to make this as easy as possible to understand, I first give you an overview of each option and show its benefits and drawbacks. This lets you see the big picture and learn which options work for which types of applications. Afterwards, I break down each option and show the steps and programming code to integrate it into your application. This is done for Windows applications as well as ASP.NET applications. If you get to the examples and something doesn’t make sense, just refer back to the beginning of the chapter for an explanation.
Sound good? Now let’s get started!
The first reporting related decision is whether the report will be previewed before it gets printed. Many users like to see the report prior to printing it so that they can verify that it will print the information they are looking for. This is especially true for reports that let the user choose how to filter and display the data. For other reports you may not want to give the user the option to preview the report. An example is a reporting application that runs a batch print job at a scheduled time during the night. Requiring user intervention would cause the program to hang indefinitely until someone arrives to push the right button. Another example is a group of standardized reports that get printed every month. It is quicker for the user to select the reports to be printed by clicking on checkboxes and printing them all at once. Since the format and filters never change, making the user preview each report is unnecessary.
Previewing reports can be done in a Windows application as well as an ASP.NET application by adding a CrystalReportViewer control to the form/web page. Using the viewer control gives you many benefits. The first is obviously that the user can see what is going to be printed prior to printing it. If it isn’t exactly what they want, they can close the preview window and repeatedly modify the report parameters until the report delivers the necessary information. No waste and another tree gets to live. Another benefit is that the viewer control has numerous built-in reporting functions that save you a lot of work. Rather than writing the code to export reports in different formats, the viewer has a button on the toolbar that does it for you. In fact, the viewer is so useful that I would guess that most of the applications you write are going to use it.
Of course, the viewer isn’t ideal for every situation. It requires user intervention for it to be useful. Another downfall of the viewer is that it can only view one report at a time. You can’t pass multiple reports to it. Displaying multiple reports simultaneously requires using multiple viewers.
If you decide to send reports directly to the printer and not use the viewer control, you are going to have to write the programming code to implement the functionality that you need. This could include writing code for printing the report, selecting the page range, and exporting the report to other formats. That’s a lot of work! Of course, Part II of this book shows you all the programming code to do this, but it’s still your responsibility to implement it in the application and test it.
If you don’t use the viewer control, there will be a certain amount of code you always have to write. This code serves as the foundation adding more reporting functionality later. Part II of this book builds upon this code for advanced runtime customization.
