Скачать или смотреть Easy Guide to Converting Strings to Int in C# from Textboxes

Learn how to effectively convert strings to integers in C# from textboxes and handle common errors like System.FormatException easily!
---
This video is based on the question https://stackoverflow.com/q/64030912/ asked by the user 'Aidan Goldie' ( https://stackoverflow.com/u/13892198/ ) and on the answer https://stackoverflow.com/a/64032278/ provided by the user 'Idle_Mind' ( https://stackoverflow.com/u/2330053/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: C# Converting String to Int from textbox

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Understanding the Issue: Converting Strings to Integers in C#

When working with user input in applications, you may often need to convert values from textboxes into integers. A common issue developers encounter is the dreaded System.FormatException, which occurs when trying to parse a string that doesn't conform to the expected format. This is particularly frustrating for new developers encountering this for the first time.

In the provided code, the user is attempting to convert the age entered in a textbox into an integer without checking if the text is in the correct format. Here’s the specific error:

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

Problematic Code

Here’s the code that led to this situation:

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

Key Issues Identified

The use of Int32.Parse() without checking the format.

Lack of validation before parsing the input, which leads to exceptions when invalid input is provided.

The Solution: Using TryParse Method

The recommended approach is to use the Int32.TryParse() method. This method attempts to convert the string to an integer and returns a boolean indicating success or failure, thus preventing exceptions from breaking your program.

Steps to Fix the Code

Replace Int32.Parse with Int32.TryParse.

Check for valid input before proceeding.

Provide user-friendly messages when input is invalid.

Improved Code

Here's how the revised code should look:

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

Explanation of the New Code

Int32.TryParse: This method is called to attempt converting the string from the textbox (txtAge.Text) into an integer (age). It handles the potential format exception internally.

Out Parameter: The out keyword allows you to return the converted integer directly while also checking if the conversion was successful.

Validation Logic:

Checks if the conversion was successful.

Validates the range of the age (0-100).

Displays appropriate messages for invalid input or when the age does not meet the required criteria.

Conclusion

By learning to use Int32.TryParse instead of Int32.Parse, not only do you enhance the robustness of your code, but you also improve user experience by providing clear and actionable feedback when they submit invalid data. Handle user inputs with care to avoid exceptions, and your applications will be much more user-friendly and reliable.

With this fix, you can now confidently convert strings to integers from textboxes in C# , being assured that your application will handle invalid inputs gracefully.