CODEWITHSUNDEEP
c#stringnull
Rubin
Rubin

Reputation: 375

How can I check if two strings match or if one is null in C#

I tried the following:

(id == title) | (id.IsNullOrEmpty) ? "class='enabled'" : ""

But it gives a message saying "Error 22 Operator '|' cannot be applied to operands of type 'bool' and 'method group'

Can anyone tell me what's wrong. Both id and title are strings.

Upvotes: 3

Views: 1355

Answers (5)

madhatter160
madhatter160

Reputation: 449

You're using bitwise OR (|). You need logical OR (||).

if ( id == null || id == title )
{
   // id is null or id equals title.
}

Note that the equality operator (==) is case sensitive. To do a case insensitive comparison use the static method String.Compare.

if ( id == null || String.Compare( id, title, true ) == 0 )
{
   // id is null or id equals title (ignoring case).
}

Upvotes: 0

Adrian Mouat
Adrian Mouat

Reputation: 46480

I'm not a C# developer, but try || instead of |. The difference between the operators is explained here http://msdn.microsoft.com/en-us/library/aa691310(v=vs.71).aspx.

Also, is == the correct way to compare strings in C#? In Java you need to use .equals().

(UPDATED: apparently | is nothing to do with the bitwise operator).

Upvotes: 5

dlev
dlev

Reputation: 48596

If you want to test for "Is this string null (or empty) or equal to another string", then just say that:

if (string.IsNullOrEmpty(id) || id.Equals(title))
{
    // Code here
}

As a ternary operation:

var result = (string.IsNullOrEmpty(id) || id.Equals(title) ? "class='enabled'" : "";

Upvotes: 0

DaveShaw
DaveShaw

Reputation: 52788

Try it like this instead:

(id == title) || id.IsNullOrEmpty() ? "class='enabled'" : ""

Upvotes: 0

JaredPar
JaredPar

Reputation: 754545

Looks like you're using | instead of || and I'm not sure if you have IsNullOrEmpty defined as an extension method but you're mussing the () to invoke it. That or just call String.IsNullOrEmpty directly.

Try the following

(id == title || String.IsNullOrEmpty(id)) ? "class='enabled'" : ""

Upvotes: 10

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