How to: Modify String Contents (C# Programming Guide)
Strings are immutable, so it is not possible to modify the contents of string. The contents of a string can, however, be extracted into a non-immutable form, modified, and then formed into a new string instance.
Example
The following example uses the ToCharArray method to extract the contents of a string into an array of the char type. Some of the elements of this array are then modified. The char array is then used to create a new string instance.
class ModifyStrings
{
static void Main()
{
string str = "The quick brown fox jumped over the fence";
System.Console.WriteLine(str);
char[] chars = str.ToCharArray();
int animalIndex = str.IndexOf("fox");
if (animalIndex != -1)
{
chars[animalIndex++] = 'c';
chars[animalIndex++] = 'a';
chars[animalIndex] = 't';
}
string str2 = new string(chars);
System.Console.WriteLine(str2);
}
}
Output
The quick brown fox jumped over the fence The quick brown cat jumped over the fence