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.NET Development
.NET Framework 3.5
StringBuilder Class
 Length Property
This page is specific to
Microsoft Visual Studio 2008/.NET Framework 3.5

Other versions are also available for the following:
.NET Framework Class Library
StringBuilder..::.Length Property

Updated: November 2007

Gets or sets the length of the current StringBuilder object.

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

Visual Basic (Declaration)
Public Property Length As Integer
Visual Basic (Usage)
Dim instance As StringBuilder
Dim value As Integer

value = instance.Length

instance.Length = value
C#
public int Length { get; set; }
Visual C++
public:
property int Length {
    int get ();
    void set (int value);
}
J#
/** @property */
public int get_Length()
/** @property */
public  void set_Length(int value)
JScript
public function get Length () : int
public function set Length (value : int)

Property Value

Type: System..::.Int32

The length of this instance.

ExceptionCondition
ArgumentOutOfRangeException

The value specified for a set operation is less than zero or greater than MaxCapacity.

Like the String..::.Length property, the Length property indicates the length of the current string object. Unlike the String..::.Length property, which is read-only, the Length property allows you to modify the length of the string stored to the StringBuilder object.

If the specified length is less than the current length, the current StringBuilder object is truncated to the specified length. If the specified length is greater than the current length, the end of the string value of the current StringBuilder object is padded with the Unicode NULL character (U+0000).

If the specified length is greater than the current capacity, Capacity is set to the specified length.

The following code example demonstrates the Length property.

Visual Basic
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#
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
*/

Visual C++
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 ) );
}

/*
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
*/

J#
// This example demonstrates StringBuilder.EnsureCapacity
//                           StringBuilder.Capacity
//                           StringBuilder.Length
//                           StringBuilder.Equals
import System.*;
import System.Text.*;

class Sample
{
    public static void main(String[] args)
    {
        StringBuilder sb1 = new StringBuilder("abc");
        StringBuilder sb2 = new StringBuilder("abc", 16);

        Console.WriteLine();
        Console.WriteLine("a1) sb1.get_Length() = {0}, " 
            + "sb1.get_Capacity() = {1}", 
            System.Convert.ToString(sb1.get_Length()), 
            System.Convert.ToString(sb1.get_Capacity()));
        Console.WriteLine("a2) sb2.get_Length() = {0}, " 
            + "sb2.get_Capacity() = {1}", 
            System.Convert.ToString(sb2.get_Length()), 
            System.Convert.ToString(sb2.get_Capacity()));
        Console.WriteLine("a3) sb1.ToString() = \"{0}\", " 
            + "sb2.ToString() = \"{1}\"", sb1.ToString(), sb2.ToString());
        Console.WriteLine("a4) sb1 equals sb2: {0}", 
            System.Convert.ToString(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.get_Length() = {0}, " 
            + "sb1.get_Capacity() = {1}", 
            System.Convert.ToString(sb1.get_Length()), 
            System.Convert.ToString(sb1.get_Capacity()));
        Console.WriteLine("b2) sb2.get_Length() = {0}, " 
            + "sb2.get_Capacity() = {1}", 
            System.Convert.ToString(sb2.get_Length()), 
            System.Convert.ToString(sb2.get_Capacity()));
        Console.WriteLine("b3) sb1.ToString() = \"{0}\", " 
            + "sb2.ToString() = \"{1}\"", sb1.ToString(), sb2.ToString());
        Console.WriteLine("b4) sb1 equals sb2: {0}", 
            System.Convert.ToString(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.set_Length(0);
        sb2.set_Capacity(51);

        Console.WriteLine();
        Console.WriteLine("c1) sb1.get_Length() = {0}, "
            + "sb1.get_Capacity() = {1}", 
            System.Convert.ToString(sb1.get_Length()), 
            System.Convert.ToString(sb1.get_Capacity()));
        Console.WriteLine("c2) sb2.get_Length() = {0}, " 
            + "sb2.get_Capacity() = {1}", 
            System.Convert.ToString(sb2.get_Length()), 
            System.Convert.ToString(sb2.get_Capacity()));
        Console.WriteLine("c3) sb1.ToString() = \"{0}\", " 
            + "sb2.ToString() = \"{1}\"", sb1.ToString(), sb2.ToString());
        Console.WriteLine("c4) sb1 equals sb2: {0}", 
            System.Convert.ToString(sb1.Equals(sb2)));
    } //main
} //Sample
/*
This example produces the following results:

a1) sb1.get_Length() = 3, sb1.get_Capacity() = 16
a2) sb2.get_Length() = 3, sb2.get_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.get_Length() = 3, sb1.get_Capacity() = 50
b2) sb2.get_Length() = 3, sb2.get_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.get_Length() = 0, sb1.get_Capacity() = 50
c2) sb2.get_Length() = 3, sb2.get_Capacity() = 51
c3) sb1.ToString() = "", sb2.ToString() = "abc"
c4) sb1 equals sb2: False
*/

Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360

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

.NET Framework

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

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 2.0, 1.0
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