Скачать или смотреть Resolving the AutoMapper.AutoMapperMappingException: Consuming an API in .NET 6 Made Easy

Encountering an `AutoMapperMappingException` while using .NET 6 to consume APIs? Learn how to resolve mapping errors step-by-step with practical code examples.
---
This video is based on the question https://stackoverflow.com/q/71992695/ asked by the user 'user1783675' ( https://stackoverflow.com/u/1783675/ ) and on the answer https://stackoverflow.com/a/71997081/ provided by the user 'Rena' ( https://stackoverflow.com/u/11398810/ ) 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: AutoMapper.AutoMapperMappingException: Missing type map configuration or unsupported mapping. Swagger Consuming another API - .net 6

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.
---
Resolving the AutoMapper.AutoMapperMappingException: Consuming an API in .NET 6 Made Easy

When building web applications in .NET 6, developers often face challenges, especially when consuming external web services. One common issue is an AutoMapperMappingException, which usually indicates a problem with the mapping configuration. In this guide, we'll explore a particular case of this exception and how to resolve it effectively while following proper coding patterns, such as the Repository pattern.

Understanding the Problem

While trying to consume a web service and upon testing the application, a developer encountered the following error:

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

This suggests that AutoMapper could not find a mapping profile that corresponds to the types involved. The developer had already set up their DTOs and models but overlooked a crucial detail in their code, especially in the method responsible for retrieving and mapping data.

Analyzing the Code

Let’s break down the relevant sections of the code to identify potential issues:

Model and DTO

Here's a summary of the essential components involved:

Model: ApplicantInfo

DTO: ApplicantInfoDto

Both classes contain similar properties that represent applicant information.

Repository Implementation

The ApplicantRepository handles fetching data from the web service:

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

This method returns an ApplicantInfo object asynchronously.

Controller Logic

In the controller, the method GetApplicantInfo attempts to map the returned data:

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

The Mapping Profile

The MappingProfiles class is correctly set up to handle the mapping between ApplicantInfo and ApplicantInfoDto.

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

Solution: Correcting the Mapping Process

Given the structure outlined above, the key to resolving this AutoMapper issue lies in correctly handling the asynchronous method and ensuring proper mapping. Here’s how to do that step-by-step:

Step 1: Adjust the Controller Method

The GetApplicantInfo method in your controller needs to be asynchronous. Change the signature to:

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

Step 2: Invoke Async Methods Properly

In the new method:

Use await to call GetApplicantInfoAsync to ensure that the method completes and returns the expected ApplicantInfo object before attempting to map it to ApplicantInfoDto.

Step 3: Validate the Result

Ensure that the data returned from the repository is valid before mapping. This prevents cases where an invalid model could cause further exceptions or errors.

Conclusion

By following the steps outlined above, you can successfully resolve the AutoMapper.AutoMapperMappingException when consuming external APIs in your .NET 6 applications. Correctly managing asynchronous calls alongside proper mapping configurations will help maintain data integrity and avoid runtime errors.

If you ever find yourself stuck, remember to revisit how your async methods are handled and ensure all necessary mappings are adequately configured in AutoMapper. Happy coding!