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Important This document may not represent best practices for current development, links to downloads and other resources may no longer be valid. Current recommended version can be found here.

How to: Search Strings Using String Methods (C# Programming Guide)

The string type, which is an alias for the System.String class, provides a number of useful methods for searching the contents of a string.

The following example uses the IndexOf, LastIndexOf, StartsWith, and EndsWith methods to search the strings.

class StringSearch
{
    static void Main()
    {
        string str = "Extension methods have all the capabilities of regular static methods.";

        // Write the string and include the quotation marks.
        System.Console.WriteLine("\"{0}\"", str);

        // Simple comparisons are always case sensitive! 
        bool test1 = str.StartsWith("extension");
        System.Console.WriteLine("Starts with \"extension\"? {0}", test1);

        // For user input and strings that will be displayed to the end user,  
        // use the StringComparison parameter on methods that have it to specify how to match strings. 
        bool test2 = str.StartsWith("extension", System.StringComparison.CurrentCultureIgnoreCase);
        System.Console.WriteLine("Starts with \"extension\"? {0} (ignoring case)", test2);

        bool test3 = str.EndsWith(".", System.StringComparison.CurrentCultureIgnoreCase);
        System.Console.WriteLine("Ends with '.'? {0}", test3);

        // This search returns the substring between two strings, so  
        // the first index is moved to the character just after the first string. 
        int first = str.IndexOf("methods") + "methods".Length;
        int last = str.LastIndexOf("methods");
        string str2 = str.Substring(first, last - first);
        System.Console.WriteLine("Substring between \"methods\" and \"methods\": '{0}'", str2);

        // Keep the console window open in debug mode
        System.Console.WriteLine("Press any key to exit.");
        System.Console.ReadKey();
    }
}
/*
Output:
"Extension methods have all the capabilities of regular static methods."
Starts with "extension"? False
Starts with "extension"? True (ignoring case)
Ends with '.'? True
Substring between "methods" and "methods": ' have all the capabilities of regular static '
Press any key to exit.     
*/

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