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Discover how to check if parameters in SSRS 2008 are empty or null with custom VB.NET code, ensuring your reports run smoothly.
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How to Efficiently Check for Empty Arrays in SSRS 2008 Custom Code: A Complete Guide

If you're working with SQL Server Reporting Services (SSRS) 2008, you may encounter the need to validate user input through parameters in your reports. One common requirement is to check if an array of parameters—especially those that allow multiple values—are empty or null. This task can seem daunting if you're new to custom code in SSRS, but fear not! We have a straightforward solution for you.

Understanding the Problem

When creating reports, it's crucial to ensure that users provide at least one valid parameter. The complexity arises particularly when dealing with parameters that can accept multiple values. As a result, checking their states can lead to ambiguity if not handled properly.

Key Insights

Parameter Types: In SSRS, parameters can either be single or multi-valued. The latter often requires special consideration when checking their state.

Use Cases: You may want to ensure that at least one parameter has been selected by the user before generating the report.

Solution Breakdown

1. Custom Code Overview

Let's start with the function you've created for two parameters—StartDate and EndDate—where you check if they are empty:

[[See Video to Reveal this Text or Code Snippet]]

This structure indicates whether both parameters are absent. However, to extend this logic to multi-valued parameters, we'll need a different approach.

2. Checking Multi-Valued Parameters

To check if one of your multi-valued parameters is empty, you can utilize the Count property as follows:

Accessing Parameter Count: In SSRS, you can check the number of values provided for a parameter with Parameters!myParameter.Count.

3. Implementing the Solution

Here’s how you can modify your custom function to check for multi-valued parameters:

Step 1: Modify the Function

You need to add a parameter count check:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Calling the Function

To call this function, you can include it in your report as follows:

[[See Video to Reveal this Text or Code Snippet]]

4. Understanding Report Behavior

While allowing null or blank parameter values might seem flexible, keep in mind that:

User Experience: If certain parameters are required, you should ensure that the report can't be run unless at least one valid parameter is selected.

SQL Handling: You can dynamically query your SQL based on the parameters supplied, which will help in cases where users select more than one parameter.

Resources for Further Learning

If you're looking to deepen your knowledge in SSRS and custom code, here are some great resources:

Books:

"SQL Server Reporting Services Recipes" by a variety of authors

"Professional SQL Server Reporting Services" by Brian Larson

Online Resources:

SQL Server Reporting Services Documentation on Microsoft’s website

Online forums and communities such as Stack Overflow can provide real-time insights and solutions.

Conclusion

Handling multi-valued parameters in SSRS 2008 using custom code doesn't have to be a headache. With the right function and understanding of how to use the parameter counts, you can ensure your reports are user-friendly and error-free. Remember to manage user input carefully to maintain the integrity of your reports!



By applying these strategies effectively, you empower users to generate accurate reports that meet their needs. Happy reporting!