使用system.datetime的编码Webtest中的空引用

Question

I was very excited to try out the new feature in VS 2012 ultimate that allows you to run whole load tests with coded web tests.

Unfortunatly, I've ran into a bit of a problem. While trying to debug a web test I've generated (and edited afterwards), I keep getting an NullReferenceException on a simple declaration line. I simply cannot wrap my head around why this occurs. Here's the code:

[Priority(0)]
public class CreateSessionCoded : WebTest
{
    public string[] SessionID;
    public string[] SessionTime;
    public string[] CreatedTime;

    public CreateSessionCoded()
    {
        this.Context.Add("Parameter1", "");
        this.PreAuthenticate = true;
    }

    public override IEnumerator<WebTestRequest> GetRequestEnumerator()
    {

        //string CurrentITR = this.Context.WebTestIteration.ToString();
        SessionID[this.Context.WebTestIteration] = Guid.NewGuid().ToString();
        SessionTime[this.Context.WebTestIteration] = System.DateTime.UtcNow.ToString();
        CreatedTime[this.Context.WebTestIteration] = System.DateTime.Now.ToString();

    ...

The code goes on, but the part where I get the NRE is at the last two lines where I try to assign values to my SessionTime and CreatedTime parameters.

It doesn't happen when assigning to the SessionID , so it's not about the WebTestIteration in any way. It also happens if I try to assign a different string (any casual string such as, say, "blabla") to the same parameters.

I'd really appreciate any help! Thanks in advance! :)

Answer 1

You define three arrays:

public string[] SessionID;
public string[] SessionTime;
public string[] CreatedTime;

But, they aren't initialized before you attempt to use them.

Basically, you are doing this:

string[] foo;
foo[1] = "bar";

And you need to do this:

string[] foo = new string[10]; // sized appropriately
foo[1] = "bar";