StringBuilder.EnsureCapacity メソッド

[アーティクル]
03/28/2008

このインスタンスの StringBuilder の容量が、指定した値以上になるようにします。

Public Function EnsureCapacity( _
   ByVal capacity As Integer _) As Integer
[C#]
public int EnsureCapacity(intcapacity);
[C++]
public: int EnsureCapacity(intcapacity);
[JScript]
public function EnsureCapacity(
   capacity : int) : int;

パラメータ

capacity
必要な最小容量。

戻り値

このインスタンスの新しい容量。

例外

例外の種類	条件
ArgumentOutOfRangeException	capacity が 0 未満です。またはこのインスタンスの値を増やすと、 MaxCapacity を超えます。

ArgumentOutOfRangeException

capacity が 0 未満です。

または

このインスタンスの値を増やすと、 MaxCapacity を超えます。

解説

現在の容量が capacity パラメータより小さい場合は、このインスタンスのメモリが capacity 文字数以上を保持するように再割り当てされます。それ以外の場合は、メモリは変更されません。

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, Common Language Infrastructure (CLI) Standard

参照

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

次の方法で共有

StringBuilder.EnsureCapacity メソッド

パラメータ

戻り値

例外

解説

使用例

必要条件

参照

その他のリソース