C# Strings Tutorial For Beginners With Examples

A string is a collection of one or more unicode characters. It is a reference type and hence managed in the Heap memory area.
The System.String class is used to declare string variables. The string keyword which is alias of System.String class can also be used to declare a string variable.

Declare and Initialize a C# String Object

A string object can be declared the same way as any other variable.
Declaration is done as below:
   string monthName;
Initialization can be done in various ways. In the below example string objects monthName andyear were assigned string literals and then multiple strings are concatenated and assigned to another string variable yearMonth.
    static void Main(string[] args)
    {
        string monthName;
        monthName = "March";
                        
        string year;
        year = "2014";

        string separator;
        separator = ":";

        //Concatenate multiple string variables
        string yearMonth = year + separator + monthName;

        Console.WriteLine(yearMonth);

        Console.ReadLine();
    }
Output:
2014:March
String class has some parameter based constructors which can also be used to initialize a string object. String constructor has seven different overloads.
In the below example a character array is passed to the constructor of string month.
    static void Main(string[] args)
    {
        Char[] monthName = { 'M', 'A', 'Y' };

        String month = new String(monthName);

        Console.WriteLine(month);

        Console.ReadLine();
    }
Output:
May
Verbatim string literals are used to ignore the escape characters. This is useful while assigning file paths or website urls to a string variable.
     
    string fileName = @"C:\Files\Name.txt";

    Console.WriteLine(fileName);

    Console.ReadLine();
Output:
C:\Files\Name.txt
All the examples discussed above are various ways of initializing a string object.

Properties of C# String Class

System.String class has two properties. Both of these are discussed below:
PropertyDescription
CharsThe Chars property is an indexer which gets the character at a specified position. There is no property with this exact name char in C# instead the indexer([]) is used.
LengthReturns the length of a string.
Below an example has been provided to explain the properties of a String class.
        
    class Program
    {
        static void Main(string[] args)
        {
            string strQuote = "Big house mouse";

            //Explains the Char property. Note the use of indexer[].
            Console.WriteLine(strQuote[4]);

            //Usage of length property is shown below
            Console.WriteLine(strQuote.Length);

            Console.ReadLine();
        }
    }
Output:
h
15

Methods of C# String class

Below we are describing some of the important methods of String class. A complete list of C# methods can be found in the MSDN site .
MethodDescription
CompareCompares two strings and returns a numeric value. A numeric value of zero means the the strings are exact. A negative numeric value means the strings do not match.
ConcatConcatenates two strings.
ContainsChecks if one string instance contains another string or not. Returns a boolean True if one string instance contains another or else false.
CopyCreates a copy of a string. The copied string is a complete new instance which contains the same characters as the old one.
EndsWithReturns a boolean True if a string ends with a specific string or else returnsFalse.
EqualsReturns a boolean value of True if two strings are equal or else returns False.
FormatFormats a string and replaces the placeholders with actual string's value.
IndexOfReturns the starting index of a string with in another string. The index always starts with zero.
InsertInserts a string with in another string instance at a specified position.
IsNullOrEmptyReturns a boolean value of True a string contains a null or empty value or else returns False.
JoinJoins an array of strings using a separator.
LastIndexOfReturns the index of the last occurrence of a character or string that is present with in another string.
RemoveRemoves all the characters starting from a specific position till the end of a string.
ReplaceReplaces a character or a string with another character or string.
SplitSplits a string using the characters specified in the split method and returns an array containing the substrings.
StartsWithOpposite of EndsWith method. Returns a boolean True if a string starts with a specific string or else returns False.
SubStringGets a substring from another string starting from a specified index.
ToCharArrayConverts a string into character array.
ToLowerConverts all the characters of a string to lower case.
ToUpperConverts all the characters of a string to upper case.
TrimTrims extra spaces or characters from beginning or end of a string.
Below example shows the usage of all the methods discussed above (Please use the scroll in the bottom of the below example to view the entire code):
    class Program
    {
        static void Main(string[] args)
        {
            string strOrganization = "Microsoft and Apple";

            string strCompanies = "Microsoft and Apple";

            //Example of String.Compare method
            Console.WriteLine("Result of String.Compare method: " + String.Compare(strOrganization, strCompanies));

            //Example of String.Concat method
            string strSearchGiant = "Google:";
            Console.WriteLine("Result of String.Concat method: " + String.Concat(strSearchGiant, strCompanies));

            //Example of Contains method
            Console.WriteLine("Result of Contains method: " + strSearchGiant.Contains("oogle"));

            //Example of String.Copy method
            string strCopy = string.Copy(strSearchGiant);
            Console.WriteLine("Result of String.Copy method: " + strCopy);

            //Example of EndsWith method            
            Console.WriteLine("Result of EndsWith method: " + strSearchGiant.EndsWith("e"));

            //Example of String.Equals method
            Console.WriteLine("Result of String.Equals method: " + string.Equals(strSearchGiant, strOrganization));

            //Example of String.Format method
            string strFormattedString = string.Format("I have a {0} house in {1}", "new", "London");
            Console.WriteLine("Result of String.Format method: " + strFormattedString);

            //Example of Insert method            
            Console.WriteLine("Result of Insert method: " + strSearchGiant.Insert(6, "Umbrella"));

            //Example of String.IsNullOrEmpty method            
            Console.WriteLine("Result of String.IsNullOrEmpty method: " + String.IsNullOrEmpty(strSearchGiant));

            //Example of String.Join method            
            string[] strArray = { "A", "B", "C" };
            Console.WriteLine("Result of String.Join method: " + String.Join(":", strArray));

            //Example of Replace method                          
            Console.WriteLine("Result of Replace method: " + strSearchGiant.Replace("o", "i"));

            //Example of Split method            
            char[] chrArray = { 'g' };
            string[] strGoogle = strSearchGiant.Split(chrArray);
            for (int i = 0; i < strGoogle.Length; i++)
            {
                Console.WriteLine("Result of Split method: " + strGoogle[i]);
            }

            //Example of StartsWith method                          
            Console.WriteLine("Result of StartsWith method: " + strSearchGiant.StartsWith("G"));

            //Example of Substring method                          
            Console.WriteLine("Result of SubString method: " + strSearchGiant.Substring(2));

            //Example of ToCharArray method                          
            char[] chrArrayFromString = strSearchGiant.ToCharArray();
            for (int i=0; i < chrArrayFromString.Length; i++)
            {
                Console.WriteLine("Result of ToCharArray method: " + chrArrayFromString[i]);
            }                
            
            //Example of ToLower method                          
            Console.WriteLine("Result of ToLower method: " + strSearchGiant.ToLower());

            //Example of ToUpper method                          
            Console.WriteLine("Result of ToUpper method: " + strSearchGiant.ToUpper());

            //Example of Trim method              
            char[] chrTrimArray = { 'G' };
            Console.WriteLine("Result of Trim method: " + strSearchGiant.Trim(chrTrimArray));

            Console.ReadLine();
        }
    }
Output:
Result of String.Compare method: 0 
Result of String.Concat method: Google:Microsoft and Apple
Result of Contains method: True
Result of String.Copy method: Google:
Result of EndsWith method: False
Result of String.Equals method: False
Result of String.Format method: I have a new house in London
Result of Insert method: GoogleUmbrella:
Result of String.IsNullOrEmpty method: False
Result of String.Join method: A:B:C
Result of Replace method: Giigle:
Result of Split method: Goo
Result of Split method: le:
Result of StartsWith method: True
Result of SubString method: ogle:
Result of ToCharArray method: G
Result of ToCharArray method: o
Result of ToCharArray method: o
Result of ToCharArray method: g
Result of ToCharArray method: l
Result of ToCharArray method: e
Result of ToCharArray method: :
Result of ToLower method: google:
Result of ToUpper method: GOOGLE:
Result of Trim method: oogle: