StringBuilder Class
Assembly: mscorlib (in mscorlib.dll)
'Declaration <SerializableAttribute> _ <ComVisibleAttribute(True)> _ Public NotInheritable Class StringBuilder Implements ISerializable 'Usage Dim instance As StringBuilder
/** @attribute SerializableAttribute() */ /** @attribute ComVisibleAttribute(true) */ public final class StringBuilder implements ISerializable
SerializableAttribute ComVisibleAttribute(true) public final class StringBuilder implements ISerializable
This class represents a string-like object whose value is a mutable sequence of characters. The value is said to be mutable because it can be modified once it has been created by appending, removing, replacing, or inserting characters. For comparison, see the String class.
Most of the methods that modify an instance of this class return a reference to that same instance. Since a reference to the instance is returned, you can call a method or property on the reference. This can be convenient if you want to write a single statement that chains successive operations one after another.
The capacity of a StringBuilder is the maximum number of characters the instance can store at any given time, and is greater than or equal to the length of the string representation of the value of the instance. The capacity can be increased or decreased with the Capacity property or EnsureCapacity method, but it cannot be less than the value of the Length property.
Implementation-specific default values are used if no capacity or maximum capacity is specified when an instance of StringBuilder is initialized.
Performance Considerations
The Concat and AppendFormat methods both concatenate new data to an existing String or StringBuilder object. A String object concatenation operation always creates a new object from the existing string and the new data. A StringBuilder object maintains a buffer to accommodate the concatenation of new data. New data is appended to the end of the buffer if room is available; otherwise, a new, larger buffer is allocated, data from the original buffer is copied to the new buffer, then the new data is appended to the new buffer.
The performance of a concatenation operation for a String or StringBuilder object depends on how often a memory allocation occurs. A String concatenation operation always allocates memory, whereas a StringBuilder concatenation operation only allocates memory if the StringBuilder object buffer is too small to accommodate the new data. Consequently, the String class is preferable for a concatenation operation if a fixed number of String objects are concatenated. In that case, the individual concatenation operations might even be combined into a single operation by the compiler. A StringBuilder object is preferable for a concatenation operation if an arbitrary number of strings are concatenated; for example, if a loop concatenates a random number of strings of user input.
Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.