CODEWITHSUNDEEP
asp.net-core.net-6.0nullable-reference-types
sDima
sDima

Reputation: 396

Dealing with NRT and MVC model binding

When I activated NRT for my project, I encountered unexpected behavior in ASP.NET model binding, if you don't pass a variable value in the URL parameters.

public IActionResult MyAction(string testString)
{
    // I assume there will be a non-null string and work with it,
    // but I get NullReferenceException, because in fact
    // for 'testString' I get null instead of String.Empty.
    string trimmedString = testString.Trim();

    // other code....

    return View();
}

How to deal with it?

One solution is to make all string in all controller action nullable so as not to deceive yourself and the compiler. Perhaps this is the wrong behavior in the .NET model binding.

Upvotes: 0

Views: 132

Answers (1)

Xinran Shen
Xinran Shen

Reputation: 9973

You can configure ConvertEmptyStringToNull to specify which property of type string can be empty instead of null.

Here i create a class with two properties of type string, One with [DisplayFormat(ConvertEmptyStringToNull = false)] attribute and o ne without

public class TestModel
{
    [DisplayFormat(ConvertEmptyStringToNull = false)]
    public string Name { get; set; }


    public string Age { get; set; }
}

Now i don't pass any value in the URl parameter. You can see the difference between them: One is empty and the other is null

enter image description here

Upvotes: 1

Related Questions