G14PS12.eps in .NET

Generator QR Code 2d barcode in .NET G14PS12.eps

14

Report Authoring with Custom Development CD-429

16 Type .15 as the Caution < parameter value. 17 Click the View Report button to preview the report and scroll to the

bottom of the page. The bottom of the report looks like this:

All values between the Alert and Caution thresholds that is, between 10% and 15% are displayed using a yellow font. There is one value displayed using a green font because the value is not within the range defined for Alert or Caution. If you scroll to the top of the report, you can see one value below the Alert threshold displayed using a red font. By combining a custom function with parameters, you can allow the user to provide the values used to set properties in the report. If you don t want to use parameter values, simply replace the applicable arguments in the expression that is used to call the custom function with constant values or expressions based on conditions elsewhere in the report. Because the function is in a custom assembly, you can reuse this logic in any report that includes a reference to the assembly. 18 Close the solution.

As you explored the stages of the reporting life cycle throughout the earlier chapters of this book, you learned about four different types of extensions used by Reporting Services data processing extensions, security extensions, rendering extensions, and delivery extensions. Of these four extensions, the easiest one to develop is a data processing extension. If you ve created a .NET data provider, you have a good foundation to get started because you can easily extend a .NET data provider with Reporting Services interfaces for use in your reporting environment.

A thorough discussion of writing custom extensions could be a whole book in itself. This chapter focuses on the key issues you need to know about when developing and using a data processing extension. Over time, you can expect to see many vendors produce custom extensions that you can integrate into your Reporting Services environment. If your requirements are sufficiently unique to require a custom extension, you can start learning more by reviewing the examples provided in this chapter and in Reporting Services Books Online.

One reason that you might need to write your own data processing extension is to use a file (such as an XML file) that you receive from a third party as a data source. XML files are rapidly becoming the structure of choice for exchanging data, so you might find it practical to develop a data processing extension to read XML data into reports. In this section, you learn how to construct and implement a very simple XML data processing extension for Reporting Services. You can, of course, extend the code in this data processing extension to add more sophisticated functionality.

To create a custom data processing extension, you build an assembly that defines how Reporting Services connects to a data source, sends a command to the data source, and retrieves data from the data source. You start by defining a namespace, to which you add the classes that contain the constructors, properties, and methods that are used by Reporting Services to interact with the data source. Then you build classes that include specific namespaces and implement the required interfaces, as shown in the following table:

14

Report Authoring with Custom Development CD-431

Namespaces Interfaces System IDbConnectionExtension Microsoft.ReportingServices.DataProcessing Microsoft.ReportingServices.Interfaces

System System.Component.Model Microsoft.ReportingServices.DataProcessing System System.Collections System.Globalization System.IO System.Security System.Security.Principal Microsoft.ReportingServices.DataProcessing System Microsoft.ReportingServices.DataProcessing System System.Collections System.Globalization Microsoft.ReportingServices.DataProcessing System Microsoft.ReportingServices.DataProcessing IDbCommand

To deploy your custom data processing extension, you move the assembly to the Reporting Services interface directories and configure Reporting Services to use the extension and to grant FullTrust permission to your extension.