CODEWITHSUNDEEP
c#asp.netnullhashtable
Melanie
Melanie

Reputation: 3111

Can't test for Null hashtable value in C# program

I have a Hashtable called EmployeeInformation in my ASP.Net 4.0 web page (written in C#) and I want to check if a particular item ("DateEff") in the Hashtable has a null value. When I walk through the code with the debugger, I see that EmployeeInformation["DateEff"] has a value of {Null}. However, when I get to this condition:

if (EmployeeInformation["Context"].ToString() != "Existing" && EmployeeInformation["DateEff"] != null && EmployeeInformation["DateEff"].ToString() != "")
     <do something here>

my code sees that all three conditions are true and continues on to the "do something here" line of code. I've tried using

string.IsNullOrEmpty(EmployeeInformation["DateEff"])

also, but the result is the same. I have also checked that EmployeeInformation contains the key DateEff and it does. Does anyone know why this is happening?

Based on MethodMan's comment below, I went back to see how I was populating the Hashtable. Here's what I'm doing:

string strDateHired = txtDateHired.Text;
            if (strDateHired == string.Empty)
                dtDateHired = SqlDateTime.Null;
            else
                dtDateHired = Convert.ToDateTime(strDateHired);
            EmployeeInformation.Add("DateEff", dtDateHired);

So the problem is that my value isn't null, it's SqlDateTime.Null. But how do I test for that? I can't convert EmployeeInformation["DateEff"] to a DateTime because it's empty.

Upvotes: 0

Views: 898

Answers (2)

bri
bri

Reputation: 3030

I think (based on your clarification) Convert.IsDBNull(DateEff) will be true. You are setting that value to DBNull, not null as defined by c#.

Fun, right!?

Upvotes: 1

Aki
Aki

Reputation: 137

If you ask for a bogus field that you know is never populated, does <do something here> ever run? If so, I would question if DataEff is getting populated when you aren't expecting it to be.

Upvotes: 0

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