Скачать или смотреть Dynamically Looping Through SqlDataReader Columns in ADO.NET to Populate C# Objects

Discover how to dynamically populate a C# object with values from SqlDataReader using ADO.NET. This guide will walk you through the process step by step!
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Dynamic Looping Through SqlDataReader Columns in ADO.NET

When working with ADO.NET, particularly using SqlDataReader, you may often face scenarios where the results returned from a stored procedure contain multiple repeating columns. In this guide, we'll tackle the problem of dynamically assigning these values to C# objects, which is essential to effectively manage structured data, especially in applications like college selection systems.

The Problem

Imagine you have an application that allows students to select colleges they wish to join, with the ability to prioritize their choices. The results from the database may include repeated columns associated with preferred colleges, like so:

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

In this result set, columns for user details are unique, while the college preferences (ID, Name, Grade, Pincode) repeat three times. To effectively handle this in our C# model, we need to utilize a data structure that can dynamically map these values.

The Data Model

Our C# model for this scenario is as follows:

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

The Solution

To retrieve the college preferences dynamically from the SqlDataReader, you can utilize a loop that iterates through the pre-defined prefixes for your college choices: "First", "Second", and "Third". Each iteration initializes a new Choice object that captures the respective data from the reader.

Here’s a step-by-step implementation of this in C# :

Define a List of Prefixes: This list will help streamline the column naming convention for your preferences.

Initialize the Choices List: Before the loop, make sure the Choices list in your User object is initialized.

Loop Through the Prefixes: For each prefix, instantiate a Choice and assign values pulled from the SqlDataReader.

Let's implement this:

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

Conclusion

By utilizing a simple loop with predefined prefixes, you can effectively map the repeated columns in your result set to a list of structured objects. This approach not only makes your code cleaner but also easily maintainable, allowing for scalable modifications in the future.

Using this strategy, your application can dynamically retrieve and manage multiple college preferences effectively. This technique is invaluable when dealing with larger datasets that require structured object representation without the need for cumbersome manual coding or hard-coded values.

Feel free to implement and test this dynamic looping technique in your own ADO.NET applications. Happy coding!