c# - What is the OR operator in an IF statement

Question

In C#, how do I specify OR:

if(this OR that) {do the other thing}

I couldn't find it in the help.

Update:

My code is:

if (title == "User greeting" || "User name") {do stuff}

and my error is:

Error 1 Operator '||' cannot be applied to operands of type 'bool' and 'string' C:Documents and SettingsSky View BarnsMy DocumentsVisual Studio 2005ProjectsFOL MinistryFOL MinistryDownloader.cs 63 21 FOL Ministry

Answer 1

|| is the conditional OR operator in C#

You probably had a hard time finding it because it's difficult to search for something whose name you don't know. Next time try doing a Google search for "C# Operators" and look at the logical operators.

Here is a list of C# operators.

My code is:

if (title == "User greeting" || "User name") {do stuff};

and my error is:

Error 1 Operator '||' cannot be applied to operands of type 'bool' and 'string' C:Documents and SettingsSky View BarnsMy DocumentsVisual Studio 2005ProjectsFOL MinistryFOL MinistryDownloader.cs 63 21 FOL Ministry

You need to do this instead:

if (title == "User greeting" || title == "User name") {do stuff};

The OR operator evaluates the expressions on both sides the same way. In your example, you are operating on the expression title == "User greeting" (a bool) and the expression "User name" (a string). These can't be combined directly without a cast or conversion, which is why you're getting the error.

In addition, it is worth noting that the || operator uses "short-circuit evaluation". This means that if the first expression evaluates to true, the second expression is not evaluated because it doesn't have to be - the end result will always be true. Sometimes you can take advantage of this during optimization.

One last quick note - I often write my conditionals with nested parentheses like this:

if ((title == "User greeting") || (title == "User name")) {do stuff};

This way I can control precedence and don't have to worry about the order of operations. It's probably overkill here, but it's especially useful when the logic gets complicated.