How do I get the collection of Model State Errors in ASP.NET MVC?
To retrieve Model State Errors in ASP.NET MVC, run a concise LINQ query on the ModelState
:
This approach extracts all the error messages into a single List<string>
, which can then be tagged for display or logging.
Digging deeper into error-management
Validating ModelState
In an ASP.NET MVC application, validation errors that occur during model binding get conveniently scooped up by the ModelState
. By checking ModelState.IsValid
, we ensure no actions are performed on invalid data:
Pinning down specific errors
To identify errors without having to execute an action, use:
For a granular view of errors pertaining to individual properties, thumb through the errors a bit:
Crafty error formatting and rendering
For a custom error summary view, consider formatting the error messages into one tidy, readable string:
LINQ to wrangle errors
LINQ's SelectMany
comes in handy to flatten nested collections while ModelState.Keys
allows you to sweep through relevant properties:
Polishing error display and enhancing controls
User experience gets a boost by marking out fields with errors. This can be established by pairing errors with relevant controls like so:
Navigating the error sea
Once errors are caught, help users fix their input:
- Traverse through
ModelState
to list errors next to form fields. - Bring errors into sharp relief with conditional CSS classes.
- Deliver quick, realtime feedback using data annotations on your models.
Accessible error handling
Strive to make your errors accessible to every user, including those using screen readers:
- Attribute
aria-invalid="true"
to inputs with errors for better accessibility. - Use
aria-live
regions for prompt feedback to screen reader users.
ModelState error handling best practices
Consider adopting these best practices:
- Log ModelState errors for auditing and troubleshooting.
- Avoid tech gibberish in error messages - be clear and actionable.
- Present errors without overwhelming users - small acts of kindness, like tooltips or inline messages, go a long way.
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