Question

I have some error correcting code, and I wanted to test to make sure that a variable assigned by “Request.Form[“checkbox”]” is either the value given when it is checked (let’s say “ticked”) or whatever the value would be if it was unchecked.

I declare the variable as an empty string before I try to assign it a value with Request.Form

I have tried the following:

if(IsGangMember != "ticked" || IsGangMember != "")
    {
        errorMessage = "The \"Search For Street Gang Member\" field contains an invalid value.";
    }

And this:

if(IsGangMember != "ticked" || IsGangMember != null)
    {
        errorMessage = "The \"Search For Street Gang Member\" field contains an invalid value.";
    }

And this:

if(IsGangMember != "ticked" || IsGangMember.IsEmpty())
    {
        errorMessage = "The \"Search For Street Gang Member\" field contains an invalid value.";
    }

I have also tried printing the value to the screen (if box is unchecked) to see it and it is, of course, empty, so I don’t see how the value could be anything other than an empty string or null.

Any help is appreciated, Thanks!

UPDATE:

Okay, all the solutions given make perfect sense but when unchecked, the error message still gets set.

This is literally all I am doing with it:

var IsGangMember = "";

Then:

IsGangMember = Request.Form["sIsGangMember"];

(sIsGangMember is the name of the input checkbox field)
Then:

if(IsGangMember != "ticked" || !String.IsNullOrEmpty(IsGangMember))
{
    errorMessage = "The \"Search For Street Gang Member\" field contains an invalid value.";
}

When left unchecked, the errorMessage still gets assigned. 🙁 Why?

Answer 1

Use String.IsNullOrEmpty

if(!String.IsNullOrEmpty(IsGangMember))
{
   //test for other values
}
else
{
   //String is empty
}

Think should be the other way round

if(IsGangMember != "ticked" || String.IsNullOrEmpty(IsGangMember))
{
    errorMessage = "The \"Search For Street Gang Member\" field contains an invalid value.";
}