StringBuilder.Capacity プロパティ

[アーティクル]
03/28/2008

現在のインスタンスによって割り当てられたメモリに格納できる最大文字数を取得または設定します。

Public Property Capacity As Integer
[C#]
public int Capacity {get; set;}
[C++]
public: __property int get_Capacity();public: __property void set_Capacity(int);
[JScript]
public function get Capacity() : int;public function set Capacity(int);

プロパティ値

現在のインスタンスによって割り当てられたメモリに格納できる最大文字数。

例外

例外の種類	条件
ArgumentOutOfRangeException	set 操作に指定された値がこのインスタンスの現在の長さを下回っています。または set 操作に指定された値が最大容量を超えています。

ArgumentOutOfRangeException

set 操作に指定された値がこのインスタンスの現在の長さを下回っています。

または

set 操作に指定された値が最大容量を超えています。

解説

Capacity は、現在のインスタンスの文字列値に影響を与えません。 Capacity を Length まで減らすことができます。

StringBuilder は、必要に応じて動的に領域を割り当て、それに応じて Capacity を増加させます。パフォーマンス上の理由により、 StringBuilder には必要以上にメモリを割り当てる場合があります。割り当てられたメモリの容量は、実装に固有です。

使用例

 
' This example demonstrates StringBuilder.EnsureCapacity
'                           StringBuilder.Capacity
'                           StringBuilder.Length
'                           StringBuilder.Equals
Imports System
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 'Main
End Class 'Sample
'
'This example produces the following results:
'
'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 = 51
'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 = 51
'c2) sb2.Length = 3, sb2.Capacity = 51
'c3) sb1.ToString() = "", sb2.ToString() = "abc"
'c4) sb1 equals sb2: False
'

[C#] 
// This example demonstrates StringBuilder.EnsureCapacity
//                           StringBuilder.Capacity
//                           StringBuilder.Length
//                           StringBuilder.Equals
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));
    }
}
/*
This example produces the following results:

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 = 51
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 = 51
c2) sb2.Length = 3, sb2.Capacity = 51
c3) sb1.ToString() = "", sb2.ToString() = "abc"
c4) sb1 equals sb2: False
*/

[C++] 
// This example demonstrates StringBuilder.EnsureCapacity
//                           StringBuilder.Capacity
//                           StringBuilder.Length
//                           StringBuilder.Equals
#using <mscorlib.dll>
using namespace System;
using namespace System::Text;

int main() 
    {
    StringBuilder* sb1 = new StringBuilder(S"abc");
    StringBuilder* sb2 = new StringBuilder(S"abc", 16);

    Console::WriteLine();
    Console::WriteLine(S"a1) sb1->Length = {0}, sb1->Capacity = {1}", __box(sb1->Length), __box(sb1->Capacity));
    Console::WriteLine(S"a2) sb2->Length = {0}, sb2->Capacity = {1}", __box(sb2->Length), __box(sb2->Capacity));
    Console::WriteLine(S"a3) sb1 = \"{0}\", sb2 = \"{1}\"",sb1,sb2);
    Console::WriteLine(S"a4) sb1 equals sb2: {0}", __box(sb1->Equals(sb2)));

    Console::WriteLine();
    Console::WriteLine(S"Ensure sb1 has a capacity of at least 50 characters.");
    sb1->EnsureCapacity(50);

    Console::WriteLine();
    Console::WriteLine(S"b1) sb1->Length = {0}, sb1->Capacity = {1}", __box(sb1->Length), __box(sb1->Capacity));
    Console::WriteLine(S"b2) sb2->Length = {0}, sb2->Capacity = {1}", __box(sb2->Length), __box(sb2->Capacity));
    Console::WriteLine(S"b3) sb1 = \"{0}\", sb2 = \"{1}\"",sb1,sb2);
    Console::WriteLine(S"b4) sb1 equals sb2: {0}", __box(sb1->Equals(sb2)));

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

    Console::WriteLine();
    Console::WriteLine(S"c1) sb1->Length = {0}, sb1->Capacity = {1}", __box(sb1->Length), __box(sb1->Capacity));
    Console::WriteLine(S"c2) sb2->Length = {0}, sb2->Capacity = {1}", __box(sb2->Length), __box(sb2->Capacity));
    Console::WriteLine(S"c3) sb1 = \"{0}\", sb2 = \"{1}\"",sb1,sb2);
    Console::WriteLine(S"c4) sb1 equals sb2: {0}", __box(sb1->Equals(sb2)));
}
/*
This example produces the following results:

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 = 51
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 = 51
c2) sb2.Length = 3, sb2.Capacity = 51
c3) sb1.ToString() = "", sb2.ToString() = "abc"
c4) sb1 equals sb2: False
*/

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必要条件

プラットフォーム: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 ファミリ, .NET Compact Framework - Windows CE .NET, Common Language Infrastructure (CLI) Standard

参照

StringBuilder クラス | StringBuilder メンバ | System.Text 名前空間

StringBuilder.Capacity プロパティ

プロパティ値

例外

解説

使用例

必要条件

参照

その他のリソース