String in my .Net MVC model returns null but a List returns fine

Question

For example in my model class

public class Dashboard
{
    public Dashboard(Account account)
    {
        AccountListName = new List<string>();
        AccountListName.Add(account.Name);

        string AccountName = account.Name;

    }
    public List<string> AccountListName { get; set; }

    public string AccountName { get; set; }

}

When I call the model in my controller.

var model = new DashBoard(account);

the model would contain the AccountListName properly but the AccountName would return null. Why does the AccountName returns null when I bind it to account.Name? Is there any weird interaction with the string type? And how do I fix this issue?

Erik Noren · Accepted Answer · 2014-02-05 21:38:17Z

2

Because you've redefined a more local scope of AccountName within your constructor that never assigns the value to your property.

string AccountName = account.Name;

Just remove the string and you should be fine. I'm surprised the compiler isn't warning you.

answered Feb 5, 2014 at 21:38

Erik Noren

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4 Comments

dazer Over a year ago

Thanks for the help. But why doesn't the AccountListName also return null as well since I also redeclared it in my constructor?

Erik Noren Over a year ago

You haven't declared it in your constructor. You've /instantiated/ it in your constructor.

Joe Brunscheon Over a year ago

You didn't re-declare it. You re-initialized it, since the auto property will initialize it for you, and then added your object to it.

Erik Noren Over a year ago

string foo; This declared a variable foo of type string. foo = "test"; This sets the variable to a value. string foo = "test"; This declares AND sets the value. In the case of your list, you've declared AccountListName as a List<string> and AccountName as string by declaring them as properties. In your constructor you're using the AccountListName declaration by instantiating a new list and adding the name. You never use the AccountName property but rather created a new variable of the same name that immediately goes out of scope at the end of the constructor.

Matthew Beatty · Accepted Answer · 2014-02-05 21:38:02Z

2

You have declared AccountName a second time in the local scope of your function. You are setting this instead of the property of dashboard.

answered Feb 5, 2014 at 21:38

Matthew Beatty

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Comments

Jason Roell · Accepted Answer · 2014-02-05 21:40:32Z

1

Use:

this.AccountName = account.Name

instead of:

string AccountName = account.Name

You've accidentally redefined your AccountName to a local variable instead of assigning your property.

answered Feb 5, 2014 at 21:40

Jason Roell

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12 Comments

Joe Brunscheon Over a year ago

The this qualifier is redundant.

Jason Roell Over a year ago

Lol no kidding. It makes it clearer to avoid issues such as these.

Jason Roell Over a year ago

I will always choose clarity.

Joe Brunscheon Over a year ago

It is not clearer as the this is implied when using Property accessors within the scope of the class. It's bad practice to have both a property and scoped variable with the same name within the same class.

Joe Brunscheon Over a year ago

Following .Net Design Guidelines and Best Practices, inner-scoped variables should not be declared with names that begin with capital letters, thus alleviating any need for the this. msdn.microsoft.com/en-us/library/ms229043.aspx

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