StringBuilder.Capacity Property
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Gets or sets the maximum number of characters that can be contained in the memory allocated by the current instance.
public:
property int Capacity { int get(); void set(int value); };
public int Capacity { get; set; }
member this.Capacity : int with get, set
Public Property Capacity As Integer
Property Value
The maximum number of characters that can be contained in the memory allocated by the current instance. Its value can range from Length to MaxCapacity.
Exceptions
The value specified for a set operation is less than the current length of this instance.
-or-
The value specified for a set operation is greater than the maximum capacity.
Examples
The following example demonstrates the Capacity property.
using namespace System;
using namespace System::Text;
int main()
{
StringBuilder^ sb1 = gcnew StringBuilder( "abc" );
StringBuilder^ sb2 = gcnew 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 = \"{0}\", sb2 = \"{1}\"", sb1, sb2 );
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 = \"{0}\", sb2 = \"{1}\"", sb1, sb2 );
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 = \"{0}\", sb2 = \"{1}\"", sb1, sb2 );
Console::WriteLine( "c4) sb1 equals sb2: {0}", sb1->Equals( sb2 ) );
}
/*
The example displays the following output:
a1) sb1->Length = 3, sb1->Capacity = 16
a2) sb2->Length = 3, sb2->Capacity = 16
a3) sb1 = "abc", sb2 = "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 = "abc", sb2 = "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 = "", sb2 = "abc"
c4) sb1 equals sb2: False
*/
using System;
using System.Text;
class Sample
{
public static void Main()
{
StringBuilder sb1 = new StringBuilder("abc");
StringBuilder sb2 = 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));
}
}
/*
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
*/
open System.Text
let sb1 = StringBuilder "abc"
let sb2 = StringBuilder("abc", 16)
printfn $"a1) sb1.Length = {sb1.Length}, sb1.Capacity = {sb1.Capacity}"
printfn $"a2) sb2.Length = {sb2.Length}, sb2.Capacity = {sb2.Capacity}"
printfn $"a3) sb1.ToString() = \"{sb1}\", sb2.ToString() = \"{sb2}\""
printfn $"a4) sb1 equals sb2: {sb1.Equals sb2}"
printfn "\nEnsure sb1 has a capacity of at least 50 characters."
sb1.EnsureCapacity 50 |> ignore
printfn $"\nb1) sb1.Length = {sb1.Length}, sb1.Capacity = {sb1.Capacity}"
printfn $"b2) sb2.Length = {sb2.Length}, sb2.Capacity = {sb2.Capacity}"
printfn $"b3) sb1.ToString() = \"{sb1}\", sb2.ToString() = \"{sb2}\""
printfn $"b4) sb1 equals sb2: {sb1.Equals sb2}"
printfn "\nSet the length of sb1 to zero."
printfn "Set the capacity of sb2 to 51 characters."
sb1.Length <- 0
sb2.Capacity <- 51
printfn $"\nc1) sb1.Length = {sb1.Length}, sb1.Capacity = {sb1.Capacity}"
printfn $"c2) sb2.Length = {sb2.Length}, sb2.Capacity = {sb2.Capacity}"
printfn $"c3) sb1.ToString() = \"{sb1}\", sb2.ToString() = \"{sb2}\""
printfn $"c4) sb1 equals sb2: {sb1.Equals sb2}"
// 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
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
Remarks
Capacity does not affect the string value of the current instance. Capacity can be decreased as long as it is not less than Length.
The StringBuilder dynamically allocates more space when required and increases Capacity accordingly. For performance reasons, a StringBuilder might allocate more memory than needed. The amount of memory allocated is implementation-specific.
Applies to
.NET