Meaning of String.Format in C# in the following context?

Question

I was just going through certain code...I wanted to know what the following code means

string format = "//User[UserName=\"{0}\" and EncryptPassword=\"{1}\"]";
string xpath = String.Format( format, userName, password );    

xpath is later used to create xPathNodeIterator object. I dont quite understand how String.Format is used and which node will the XPathNodeIterator will be iterating through if I iterate?

Answer 1

Read the details of String.Format. It

Replaces each format item in a specified string with the text equivalent of a corresponding object's value.

it means that xpath will contain format string where {0} in the format string will be replaced with value of username and {1} will be replaced with value of password

Assuming that

string userName = "Ehsan";
string password = "Password";
string format = "//User[UserName=\"{0}\" and EncryptPassword=\"{1}\"]";
string xpath = String.Format(format, userName, password);  

Xpath will be equivalent to

//User[UserName="Ehsan" and EncryptPassword="Password"]