Check if an initialized array is null

Question

I have a controller action where I validate if any value is entered in fields or not. Here is how I do it:

[HttpPost]
        public ActionResult ValidateFields(string Desc, string Status, string Name )
        {
            string[] fields = new string[3];

            if (string.IsNullOrEmpty(Desc))
                fields[0] = "#Desc";

            if (string.IsNullOrEmpty(Status))
                fields[1] = "#Status";

            if (string.IsNullOrEmpty(Name))
                fields[2] = "#Name ";

// Check if the initialized array "fields" has any items in it.
            if (fields != null)
            { return content("Please enter valid values for " + fields); }

            return content("Validation Successful");
        }

Here array "fields" is initialized and hence its length is never 0. Also, checking for null does not work. All I can do i loop through the array and check if it has any items in it.

Is there a better way of checking if an array has any items in it or just null values?

Also, if there is any better way of validating fields than how I am doing, please let me know. I want it to be maintainable, if tomorrow I add new fields I want to spend as little time I can to validating them.

Brian Rasmussen · Accepted Answer · 2013-01-15 18:52:31Z

4

Why don't you use a List<string> instead? That will allow you to add each of the fields and then you could check the length of the list.

answered Jan 15, 2013 at 18:52

Brian Rasmussen

117k34 gold badges227 silver badges325 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Maarten · Accepted Answer · 2013-01-15 19:01:16Z

2

Use lists.

    [HttpPost]
    public ActionResult ValidateFields(string Desc, string Status, string Name )
    {
        List<string> fields = new List<string>();

        if (string.IsNullOrEmpty(Desc))
            fields.Add("#Desc");

        if (string.IsNullOrEmpty(Status))
            fields.Add("#Status");

        if (string.IsNullOrEmpty(Name))
            fields.Add("#Name");

        // Check if the list "fields" has any items in it.
        if (fields.Any()) {
             return content("Please enter valid values for " + string.Join(", ", fields)); 
        }

        return content("Validation Successful");
    }

UPDATE

Another, probably better and more maintainable, way to validate is to create a model class, and add validation attributes. See here.

edited Jan 15, 2013 at 19:01

answered Jan 15, 2013 at 18:54

Maarten

23k3 gold badges51 silver badges69 bronze badges

Comments

djs · Accepted Answer · 2013-01-15 18:57:48Z

2

I believe you can do:

if (fields.Any(f => !string.IsNullOrEmpty(f)))

answered Jan 15, 2013 at 18:57

djs

2301 silver badge5 bronze badges

Comments

Sławomir Rosiek · Accepted Answer · 2013-01-15 19:01:20Z

1

You can also do it for array. Just invoke:

fields.Any(i => i != null)

You can also improve your validation by using built-in ASP.NET MVC validation mechanism.

edited Jan 15, 2013 at 19:01

answered Jan 15, 2013 at 18:55

Sławomir Rosiek

4,0733 gold badges28 silver badges44 bronze badges

Collectives™ on Stack Overflow

Check if an initialized array is null

4 Answers 4

Comments

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related