StringBuilder.Append Method (Char, Int32)

The Append(Char, Int32) method modifies the existing instance of this class; it does not return a new class instance. Because of this, you can call a method or property on the existing reference and you do not have to assign the return value to a StringBuilder object, as the following example illustrates.

decimal value = 1346.19m;
System.Text.StringBuilder sb = new System.Text.StringBuilder();
sb.Append('*', 5).AppendFormat("{0:C2}", value).Append('*', 5);
Console.WriteLine(sb);
// The example displays the following output: 
//       *****$1,346.19*****

The capacity of this instance is adjusted as needed.

In the .NET Framework 4 and the .NET Framework 4.5, when you instantiate the StringBuilder object by calling the StringBuilder(Int32, Int32) constructor, both the length and the capacity of the StringBuilder instance can grow beyond the value of its MaxCapacity property. This can occur particularly when you call the Append and AppendFormat methods to append small strings.

.NET Framework

.NET Framework Client Profile

Portable Class Library

.NET for Windows Store apps

Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Reference