Статья
11/17/2011

StringBuilder.Append Method (Object)

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Updated: January 2011

Appends the string representation of a specified object to the end of this instance.

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

Syntax

'Declaration
Public Function Append ( _
    value As Object _
) As StringBuilder

public StringBuilder Append(
    Object value
)

Parameters

value
Type: System.Object
The object to append.

Return Value

Type: System.Text.StringBuilder
A reference to this instance after the append operation has completed.

Exceptions

Exception	Condition
ArgumentOutOfRangeException	Enlarging the value of this instance would exceed its maximum capacity.

Remarks

The Append method modifies the existing instance of this class; it does not return a new class instance. Because of this, you can call a method or property on the existing reference and you do not have to assign the return value to a StringBuilder object, as the following example illustrates. It defines a Dog class, creates a Dog object, and makes three calls to the Append method to create a string that contains the dog's name and breed.

Public Class Dog
   Private dogBreed As String
   Private dogName As String

   Public Sub New(name As String, breed As String)
      Me.dogName = name
      Me.dogBreed = breed
   End Sub

   Public ReadOnly Property Breed As String
      Get
         Return Me.dogBreed
      End Get
   End Property

   Public ReadOnly Property Name As String
      Get
         Return Me.dogName
      End Get
   End Property

   Public Overrides Function ToString() As String
      Return Me.dogName
   End Function
End Class

Module Example
   Public Sub Demo(outputBlock As System.Windows.Controls.TextBlock)
      Dim dog1 As New Dog("Yiska", "Alaskan Malamute")
      Dim sb As New System.Text.StringBuilder()     
      sb.Append(dog1).Append(", Breed: ").Append(dog1.Breed)  
      outputBlock.Text += sb.ToString() + vbCrLf
   End Sub
End Module
' The example displays the following output:
'       Yiska, Breed: Alaskan Malamute

using System;

public class Dog
{
   private string dogBreed;
   private string dogName;

   public Dog(string name, string breed)
   {
      this.dogName = name;
      this.dogBreed = breed;
   }

   public string Breed {
      get { return this.dogBreed; }
   }

   public string Name {
      get { return this.dogName; }
   }

   public override string ToString()
   {
      return this.dogName;
   }
}

public class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      Dog dog1 = new Dog("Yiska", "Alaskan Malamute");
      System.Text.StringBuilder sb = new System.Text.StringBuilder();     
      sb.Append(dog1).Append(", Breed: ").Append(dog1.Breed);  
      outputBlock.Text += sb.ToString() + Environment.NewLine;
   }
}
// The example displays the following output:
//        Yiska, Breed: Alaskan Malamute

The Append method calls the Object.ToString method to get the string representation of value. If value is nulla null reference (Nothing in Visual Basic), no changes are made to the StringBuilder object.

The capacity of this instance is adjusted as needed.

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

Change History

Date	History	Reason
January 2011	Expanded the Remarks section and removed the example.	Customer feedback.

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