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StringBuilder.EnsureCapacity Method

Ensures that the capacity of this instance of StringBuilder is at least the specified value.

Namespace:  System.Text
Assembly:  mscorlib (in mscorlib.dll)

'Declaration
Public Function EnsureCapacity ( _
	capacity As Integer _
) As Integer

Parameters

capacity
Type: System.Int32
The minimum capacity to ensure.

Return Value

Type: System.Int32
The new capacity of this instance.

ExceptionCondition
ArgumentOutOfRangeException

capacity is less than zero.

-or-

Enlarging the value of this instance would exceed MaxCapacity.

If the current capacity is less than the capacity parameter, memory for this instance is reallocated to hold at least capacity number of characters; otherwise, no memory is changed.

The following example demonstrates the EnsureCapacity method.


Imports System.Text

Class Sample
   Public Shared Sub Main()
      Dim sb1 As New StringBuilder("abc")
      Dim sb2 As New StringBuilder("abc", 16)

      Console.WriteLine()
      Console.WriteLine("a1) sb1.Length = {0}, sb1.Capacity = {1}", sb1.Length, sb1.Capacity)
      Console.WriteLine("a2) sb2.Length = {0}, sb2.Capacity = {1}", sb2.Length, sb2.Capacity)
      Console.WriteLine("a3) sb1.ToString() = ""{0}"", sb2.ToString() = ""{1}""", _
                             sb1.ToString(),           sb2.ToString())
      Console.WriteLine("a4) sb1 equals sb2: {0}", sb1.Equals(sb2))

      Console.WriteLine()
      Console.WriteLine("Ensure sb1 has a capacity of at least 50 characters.")
      sb1.EnsureCapacity(50)

      Console.WriteLine()
      Console.WriteLine("b1) sb1.Length = {0}, sb1.Capacity = {1}", sb1.Length, sb1.Capacity)
      Console.WriteLine("b2) sb2.Length = {0}, sb2.Capacity = {1}", sb2.Length, sb2.Capacity)
      Console.WriteLine("b3) sb1.ToString() = ""{0}"", sb2.ToString() = ""{1}""", _
                             sb1.ToString(),           sb2.ToString())
      Console.WriteLine("b4) sb1 equals sb2: {0}", sb1.Equals(sb2))

      Console.WriteLine()
      Console.WriteLine("Set the length of sb1 to zero.")
      Console.WriteLine("Set the capacity of sb2 to 51 characters.")
      sb1.Length = 0
      sb2.Capacity = 51

      Console.WriteLine()
      Console.WriteLine("c1) sb1.Length = {0}, sb1.Capacity = {1}", sb1.Length, sb1.Capacity)
      Console.WriteLine("c2) sb2.Length = {0}, sb2.Capacity = {1}", sb2.Length, sb2.Capacity)
      Console.WriteLine("c3) sb1.ToString() = ""{0}"", sb2.ToString() = ""{1}""", _
                             sb1.ToString(),           sb2.ToString())
      Console.WriteLine("c4) sb1 equals sb2: {0}", sb1.Equals(sb2))
   End Sub 
End Class
'The example displays the following output:
'       a1) sb1.Length = 3, sb1.Capacity = 16
'       a2) sb2.Length = 3, sb2.Capacity = 16
'       a3) sb1.ToString() = "abc", sb2.ToString() = "abc"
'       a4) sb1 equals sb2: True
'       
'       Ensure sb1 has a capacity of at least 50 characters.
'       
'       b1) sb1.Length = 3, sb1.Capacity = 50
'       b2) sb2.Length = 3, sb2.Capacity = 16
'       b3) sb1.ToString() = "abc", sb2.ToString() = "abc"
'       b4) sb1 equals sb2: False
'       
'       Set the length of sb1 to zero.
'       Set the capacity of sb2 to 51 characters.
'       
'       c1) sb1.Length = 0, sb1.Capacity = 50
'       c2) sb2.Length = 3, sb2.Capacity = 51
'       c3) sb1.ToString() = "", sb2.ToString() = "abc"
'       c4) sb1 equals sb2: False


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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

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