StringBuilder.Capacity Vlastnost

Definice

Obor názvů:

System.Text

Sestavení:

netstandard.dll, System.Runtime.dll

Zdroj:

StringBuilder.cs

Získá nebo nastaví maximální počet znaků, které mohou být obsaženy v paměti přidělené aktuální 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

Hodnota vlastnosti

Int32

Maximální počet znaků, které mohou být obsaženy v paměti přidělené aktuální instanci. Jeho hodnota může být v rozsahu od Length do MaxCapacity.

Výjimky

ArgumentOutOfRangeException

Hodnota zadaná pro operaci sady je menší než aktuální délka této instance.

nebo

Hodnota zadaná pro operaci sady je větší než maximální kapacita.

Příklady

Následující příklad ukazuje Capacity vlastnost.

using System;
using System.Text;

StringBuilder sb1 = new("abc");
StringBuilder sb2 = new("abc", 16);

Console.WriteLine();
Console.WriteLine($"a1) sb1.Length = {sb1.Length}, sb1.Capacity = {sb1.Capacity}");
Console.WriteLine($"a2) sb2.Length = {sb2.Length}, sb2.Capacity = {sb2.Capacity}");
Console.WriteLine($"a3) sb1.ToString() = \"{sb1}\", sb2.ToString() = \"{sb2}\"");
Console.WriteLine($"a4) sb1 equals sb2: {sb1.Equals(sb2)}");

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

Console.WriteLine();
Console.WriteLine($"b1) sb1.Length = {sb1.Length}, sb1.Capacity = {sb1.Capacity}");
Console.WriteLine($"b2) sb2.Length = {sb2.Length}, sb2.Capacity = {sb2.Capacity}");
Console.WriteLine($"b3) sb1.ToString() = \"{sb1}\", sb2.ToString() = \"{sb2}\"");
Console.WriteLine($"b4) sb1 equals sb2: {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($"c1) sb1.Length = {sb1.Length}, sb1.Capacity = {sb1.Capacity}");
Console.WriteLine($"c2) sb2.Length = {sb2.Length}, sb2.Capacity = {sb2.Capacity}");
Console.WriteLine($"c3) sb1.ToString() = \"{sb1}\", sb2.ToString() = \"{sb2}\"");
Console.WriteLine($"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: True (False on .NET Framework)

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: True (False on .NET Framework)
//       
//       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: True (False on .NET Framework)
'       
'       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

Poznámky

Capacity nemá vliv na řetězcovou hodnotu aktuální instance. Capacity lze snížit, pokud není menší než Length.

Dynamicky StringBuilder přiděluje více místa v případě potřeby a odpovídajícím způsobem se zvýší Capacity . Z důvodů výkonu StringBuilder může přidělit více paměti, než je potřeba. Množství přidělené paměti je specifické pro implementaci.