how to compare two strings in c#?

It might be helpful,

How to: Compare Strings[^]

:)

Try as below code.

For Case Sensitive Comparison.

string string1 = "Something";
string string2 = "Something";

if (string1.Equals(string2,StringComparison.Ordinal))
{
 //Strings are Equal
}
else
{
 //Strings are not Equal
}

For Case Insensitive Comparison.

string string1 = "Something";
string string2 = "Something";

if (string1.Equals(string2,StringComparison.OrdinalIgnoreCase))
{
 //Strings are Equal
}
else
{
 //Strings are not Equal
}

Compair String

A "comparison" should mean "equal":

string first = //...
string second = //...
if (first == second)
   //then something

Trivial, isn't it? Now, it's good to know, that 1) string is a reference type, but quite unusual type: is perfectly simulates "value semantics"; 2) for every reference type, there can be two (or three) different equivalences; referential and "semantic"; the referential equivalence is absolute and is returned by the method object.ReferenceEquals while "semantic" equivalence is defined by the virtual instance method object.Equals which can be overridden to change the "semantic" equivalence. It stands for all types, not only classes. Also, in any type one can re-redefine the operators "==" and "!=" (only both of them!) which affect comparison just using this operators, specifically. Mismatch between "==", "!=" and <code>object.Equals</code> is possible and would present a pathological case, so elementary requirements of sanity demand matching result of "semantic" comparison.

See http://msdn.microsoft.com/en-us/library/system.object.aspx[^].

Now, what's so unusual with strings? The CLR conserves string storage by maintaining a table, called the intern pool, that contains a single reference to each unique literal string declared or created programmatically in your program. So, an instance of a literal string with a particular value only exists once in the system.

There is a method to make sure that the semantic equivalence of the strings would cause referential equivalence. This is called interning. See the static methods System.String.IsInterned and System.String.Inter. See the explanations and a code sample here: http://msdn.microsoft.com/en-us/library/system.string.intern.aspx[^].

—SA