StringBuilder.AppendFormat StringBuilder.AppendFormat StringBuilder.AppendFormat StringBuilder.AppendFormat Method

Definition

Appends the string returned by processing a composite format string, which contains zero or more format items, to this instance. Each format item is replaced by the string representation of a corresponding object argument.

Overloads

AppendFormat(IFormatProvider, String, Object, Object, Object) AppendFormat(IFormatProvider, String, Object, Object, Object) AppendFormat(IFormatProvider, String, Object, Object, Object) AppendFormat(IFormatProvider, String, Object, Object, Object)

Appends the string returned by processing a composite format string, which contains zero or more format items, to this instance. Each format item is replaced by the string representation of either of three arguments using a specified format provider.

AppendFormat(String, Object) AppendFormat(String, Object) AppendFormat(String, Object) AppendFormat(String, Object)

Appends the string returned by processing a composite format string, which contains zero or more format items, to this instance. Each format item is replaced by the string representation of a single argument.

AppendFormat(String, Object[]) AppendFormat(String, Object[]) AppendFormat(String, Object[]) AppendFormat(String, Object[])

Appends the string returned by processing a composite format string, which contains zero or more format items, to this instance. Each format item is replaced by the string representation of a corresponding argument in a parameter array.

AppendFormat(IFormatProvider, String, Object) AppendFormat(IFormatProvider, String, Object) AppendFormat(IFormatProvider, String, Object) AppendFormat(IFormatProvider, String, Object)

Appends the string returned by processing a composite format string, which contains zero or more format items, to this instance. Each format item is replaced by the string representation of a single argument using a specified format provider.

AppendFormat(IFormatProvider, String, Object[]) AppendFormat(IFormatProvider, String, Object[]) AppendFormat(IFormatProvider, String, Object[]) AppendFormat(IFormatProvider, String, Object[])

Appends the string returned by processing a composite format string, which contains zero or more format items, to this instance. Each format item is replaced by the string representation of a corresponding argument in a parameter array using a specified format provider.

AppendFormat(String, Object, Object) AppendFormat(String, Object, Object) AppendFormat(String, Object, Object) AppendFormat(String, Object, Object)

Appends the string returned by processing a composite format string, which contains zero or more format items, to this instance. Each format item is replaced by the string representation of either of two arguments.

AppendFormat(IFormatProvider, String, Object, Object) AppendFormat(IFormatProvider, String, Object, Object) AppendFormat(IFormatProvider, String, Object, Object) AppendFormat(IFormatProvider, String, Object, Object)

Appends the string returned by processing a composite format string, which contains zero or more format items, to this instance. Each format item is replaced by the string representation of either of two arguments using a specified format provider.

AppendFormat(String, Object, Object, Object) AppendFormat(String, Object, Object, Object) AppendFormat(String, Object, Object, Object) AppendFormat(String, Object, Object, Object)

Appends the string returned by processing a composite format string, which contains zero or more format items, to this instance. Each format item is replaced by the string representation of either of three arguments.

AppendFormat(IFormatProvider, String, Object, Object, Object) AppendFormat(IFormatProvider, String, Object, Object, Object) AppendFormat(IFormatProvider, String, Object, Object, Object) AppendFormat(IFormatProvider, String, Object, Object, Object)

Appends the string returned by processing a composite format string, which contains zero or more format items, to this instance. Each format item is replaced by the string representation of either of three arguments using a specified format provider.

public:
 System::Text::StringBuilder ^ AppendFormat(IFormatProvider ^ provider, System::String ^ format, System::Object ^ arg0, System::Object ^ arg1, System::Object ^ arg2);
public System.Text.StringBuilder AppendFormat (IFormatProvider provider, string format, object arg0, object arg1, object arg2);
member this.AppendFormat : IFormatProvider * string * obj * obj * obj -> System.Text.StringBuilder
Public Function AppendFormat (provider As IFormatProvider, format As String, arg0 As Object, arg1 As Object, arg2 As Object) As StringBuilder

Parameters

provider
IFormatProvider IFormatProvider IFormatProvider IFormatProvider

An object that supplies culture-specific formatting information.

format
String String String String

A composite format string.

arg0
Object Object Object Object

The first object to format.

arg1
Object Object Object Object

The second object to format.

arg2
Object Object Object Object

The third object to format.

Returns

A reference to this instance after the append operation has completed. After the append operation, this instance contains any data that existed before the operation, suffixed by a copy of format where any format specification is replaced by the string representation of the corresponding object argument.

Exceptions

format is invalid.

-or-

The index of a format item is less than 0 (zero), or greater than or equal to 3 (three).

Examples

The following example uses the AppendFormat(IFormatProvider, String, Object, Object, Object) method to illustrate the result of a Boolean And operation with integer values. Note that the format string includes six format items, but the method has only three items in its argument list, because each item is formatted in two different ways.

using System;
using System.Globalization;
using System.Text;

public class Example
{
   public static void Main()
   {
      Random rnd = new Random();
      CultureInfo culture = CultureInfo.CreateSpecificCulture("fr-FR");
      StringBuilder sb = new StringBuilder();
      string formatString = "    {0,12:N0} ({0,8:X8})\n" +
                            "And {1,12:N0} ({1,8:X8})\n" +
                            "  = {2,12:N0} ({2,8:X8})\n";
      for (int ctr = 0; ctr <= 2; ctr++) {
         int value1 = rnd.Next();
         int value2 = rnd.Next();
         sb.AppendFormat(culture, formatString,
                         value1, value2, value1 & value2).
                         AppendLine();
      }
      Console.WriteLine(sb.ToString());
   }
}
// The example displays output like the following:
//           1 984 112 195 (76432643)
//       And 1 179 778 511 (4651FDCF)
//         = 1 178 674 243 (46412443)
//
//           2 034 813 710 (7948CB0E)
//       And  569 333 976 (21EF58D8)
//         =  558 385 160 (21484808)
//
//            126 717 735 (078D8F27)
//       And 1 830 715 973 (6D1E8245)
//         =   84 705 797 (050C8205)
Imports System.Globalization
Imports System.Text

Public Module Example
   Public Sub Main()
      Dim rnd As New Random()
      Dim culture As CultureInfo = CultureInfo.CreateSpecificCulture("fr-FR")
      Dim sb As New StringBuilder()
      Dim formatString As String = "    {0,12:N0} ({0,8:X8})" + vbCrLf +
                                   "And {1,12:N0} ({1,8:X8})" + vbCrLf +
                                   "  = {2,12:N0} ({2,8:X8})" + vbCrLf
      For ctr As Integer = 0 To 2
         Dim value1 As Integer = rnd.Next()
         Dim value2 As Integer = rnd.Next()
         sb.AppendFormat(culture, formatString,
                         value1, value2, value1 And value2).AppendLine()
      Next
      Console.WriteLine(sb.ToString())
   End Sub
End Module
' The example displays the following output:
'           1 984 112 195 (76432643)
'       And 1 179 778 511 (4651FDCF)
'         = 1 178 674 243 (46412443)
'
'           2 034 813 710 (7948CB0E)
'       And  569 333 976 (21EF58D8)
'         =  558 385 160 (21484808)
'
'            126 717 735 (078D8F27)
'       And 1 830 715 973 (6D1E8245)
'         =   84 705 797 (050C8205)

Remarks

This method uses the composite formatting feature of the .NET Framework to convert the value of an object to its text representation and embed that representation in the current StringBuilder object.

The format parameter consists of zero or more runs of text intermixed with zero or more indexed placeholders, called format items, that correspond to objects in the parameter list of this method. The formatting process replaces each format item with the string representation of the corresponding object.

The syntax of a format item is as follows:

{index[,length][:formatString]}

Elements in square brackets are optional. The following table describes each element.

Element Description
index The zero-based position in the parameter list of the object to be formatted. If the object specified by index is null, the format item is replaced by String.Empty. If there is no parameter in the index position, a FormatException is thrown.
,length The minimum number of characters in the string representation of the parameter. If positive, the parameter is right-aligned; if negative, it is left-aligned.
:formatString A standard or custom format string that is supported by the parameter.

Note

For the standard and custom format strings used with date and time values, see Standard Date and Time Format Strings and Custom Date and Time Format Strings. For the standard and custom format strings used with numeric values, see Standard Numeric Format Strings and Custom Numeric Format Strings. For the standard format strings used with enumerations, see Enumeration Format Strings.

The provider parameter specifies an IFormatProvider implementation that can provide formatting information for arg0 and arg1. provider can be any of the following:

  • A CultureInfo object that provides culture-specific formatting information.

  • A NumberFormatInfo object that provides culture-specific formatting information for arg0 or arg1 if they are numeric values.

  • A DateTimeFormatInfo object that provides culture-specific formatting information for arg0, arg1, or arg2 if they are date and time values.

  • A custom IFormatProvider implementation that provides formatting information for arg0, arg1, and arg2. Typically, such an implementation also implements the ICustomFormatter interface.

If the provider parameter is null, format provider information is obtained from the current culture.

arg0, arg1, and arg2 represent the objects to be formatted. Each format item in format is replaced with the string representation of the object that has the corresponding index. If the format item includes formatString and the corresponding argument implements the IFormattable interface, then the argument's ToString(formatString, provider) method defines the formatting. Otherwise, the argument's ToString() method defines the formatting.

Notes to Callers

In .NET Core and in the .NET Framework 4.0 and later versions, when you instantiate the StringBuilder object by calling the StringBuilder(Int32, Int32) constructor, both the length and the capacity of the StringBuilder instance can grow beyond the value of its MaxCapacity property. This can occur particularly when you call the Append(String) and AppendFormat(String, Object) methods to append small strings.

See also

AppendFormat(String, Object) AppendFormat(String, Object) AppendFormat(String, Object) AppendFormat(String, Object)

Appends the string returned by processing a composite format string, which contains zero or more format items, to this instance. Each format item is replaced by the string representation of a single argument.

public:
 System::Text::StringBuilder ^ AppendFormat(System::String ^ format, System::Object ^ arg0);
public System.Text.StringBuilder AppendFormat (string format, object arg0);
member this.AppendFormat : string * obj -> System.Text.StringBuilder
Public Function AppendFormat (format As String, arg0 As Object) As StringBuilder

Parameters

format
String String String String

A composite format string.

arg0
Object Object Object Object

An object to format.

Returns

A reference to this instance with format appended. Each format item in format is replaced by the string representation of arg0.

Exceptions

format is invalid.

-or-

The index of a format item is less than 0 (zero), or greater than or equal to 1.

Examples

The following example demonstrates the AppendFormat method.

using namespace System;
using namespace System::Text;
using namespace System::Globalization;
void Show( StringBuilder^ sbs )
{
   Console::WriteLine( sbs );
   sbs->Length = 0;
}

int main()
{
   StringBuilder^ sb = gcnew StringBuilder;
   int var1 = 111;
   float var2 = 2.22F;
   String^ var3 = "abcd";
   array<Object^>^var4 = {3,4.4,(Char)'X'};
   Console::WriteLine();
   Console::WriteLine( "StringBuilder.AppendFormat method:" );
   sb->AppendFormat( "1) {0}", var1 );
   Show( sb );
   sb->AppendFormat( "2) {0}, {1}", var1, var2 );
   Show( sb );
   sb->AppendFormat( "3) {0}, {1}, {2}", var1, var2, var3 );
   Show( sb );
   sb->AppendFormat( "4) {0}, {1}, {2}", var4 );
   Show( sb );
   CultureInfo^ ci = gcnew CultureInfo( "es-ES",true );
   array<Object^>^temp1 = {var2};
   sb->AppendFormat( ci, "5) {0}", temp1 );
   Show( sb );
}

/*
This example produces the following results:

StringBuilder.AppendFormat method:
1) 111
2) 111, 2.22
3) 111, 2.22, abcd
4) 3, 4.4, X
5) 2,22
*/
using System;
using System.Text;
using System.Globalization;

class Sample 
{
    static StringBuilder sb = new StringBuilder();

    public static void Main() 
    {
    int    var1   = 111;
    float  var2   = 2.22F;
    string var3   = "abcd";
    object[] var4 = {3, 4.4, 'X'};

    Console.WriteLine();
    Console.WriteLine("StringBuilder.AppendFormat method:");
    sb.AppendFormat("1) {0}", var1);
    Show(sb);
    sb.AppendFormat("2) {0}, {1}", var1, var2);
    Show(sb);
    sb.AppendFormat("3) {0}, {1}, {2}", var1, var2, var3);
    Show(sb);
    sb.AppendFormat("4) {0}, {1}, {2}", var4);
    Show(sb);
    CultureInfo ci = new CultureInfo("es-ES", true);
    sb.AppendFormat(ci, "5) {0}", var2);
    Show(sb);
    }

    public static void Show(StringBuilder sbs)
    {
    Console.WriteLine(sbs.ToString());
    sb.Length = 0;
    }
}
/*
This example produces the following results:

StringBuilder.AppendFormat method:
1) 111
2) 111, 2.22
3) 111, 2.22, abcd
4) 3, 4.4, X
5) 2,22
*/
Imports System
Imports System.Text
Imports System.Globalization

Class Sample
   Private Shared sb As New StringBuilder()

   Public Shared Sub Main()
      Dim var1 As Integer = 111
      Dim var2 As Single = 2.22F
      Dim var3 As String = "abcd"
      Dim var4 As Object() =  {3, 4.4, "X"c}
      
      Console.WriteLine()
      Console.WriteLine("StringBuilder.AppendFormat method:")
      sb.AppendFormat("1) {0}", var1)
      Show(sb)
      sb.AppendFormat("2) {0}, {1}", var1, var2)
      Show(sb)
      sb.AppendFormat("3) {0}, {1}, {2}", var1, var2, var3)
      Show(sb)
      sb.AppendFormat("4) {0}, {1}, {2}", var4)
      Show(sb)
      Dim ci As New CultureInfo("es-ES", True)
      sb.AppendFormat(ci, "5) {0}", var2)
      Show(sb)
   End Sub 'Main
   
   Public Shared Sub Show(sbs As StringBuilder)
      Console.WriteLine(sbs.ToString())
      sb.Length = 0
   End Sub 'Show
End Class 'Sample
'
'This example produces the following results:
'
'StringBuilder.AppendFormat method:
'1) 111
'2) 111, 2.22
'3) 111, 2.22, abcd
'4) 3, 4.4, X
'5) 2,22

Remarks

This method uses the composite formatting feature of the .NET Framework to convert the value of an object to its text representation and embed that representation in the current StringBuilder object.

The format parameter consists of zero or more runs of text intermixed with zero or more indexed placeholders, called format items. The index of the format items must be 0, to correspond to arg0, the single object in the parameter list of this method. The formatting process replaces each format item with the string representation of arg0.

The syntax of a format item is as follows:

{index[,length][:formatString]}

Elements in square brackets are optional. The following table describes each element.

Element Description
index The zero-based position in the parameter list of the object to be formatted. If the object specified by index is null, the format item is replaced by String.Empty. If there is no parameter in the index position, a FormatException is thrown.
,length The minimum number of characters in the string representation of the parameter. If positive, the parameter is right-aligned; if negative, it is left-aligned.
:formatString A standard or custom format string that is supported by the parameter.

Note

For the standard and custom format strings used with date and time values, see Standard Date and Time Format Strings and Custom Date and Time Format Strings. For the standard and custom format strings used with numeric values, see Standard Numeric Format Strings and Custom Numeric Format Strings. For the standard format strings used with enumerations, see Enumeration Format Strings.

arg0 represents the object to be formatted. Each format item in format is replaced with the string representation of arg0. If the format item includes formatString and arg0 implements the IFormattable interface, then arg0.ToString(formatString, null) defines the formatting. Otherwise, arg0.ToString() defines the formatting.

If the string assigned to format is "Thank you for your donation of {0:####} cans of food to our charitable organization." and arg0 is an integer with the value 10, the return value will be "Thank you for your donation of 10 cans of food to our charitable organization."

Notes to Callers

In .NET Core and in the .NET Framework 4.0 and later versions, when you instantiate the StringBuilder object by calling the StringBuilder(Int32, Int32) constructor, both the length and the capacity of the StringBuilder instance can grow beyond the value of its MaxCapacity property. This can occur particularly when you call the Append(String) and AppendFormat(String, Object) methods to append small strings.

See also

AppendFormat(String, Object[]) AppendFormat(String, Object[]) AppendFormat(String, Object[]) AppendFormat(String, Object[])

Appends the string returned by processing a composite format string, which contains zero or more format items, to this instance. Each format item is replaced by the string representation of a corresponding argument in a parameter array.

public:
 System::Text::StringBuilder ^ AppendFormat(System::String ^ format, ... cli::array <System::Object ^> ^ args);
public System.Text.StringBuilder AppendFormat (string format, params object[] args);
member this.AppendFormat : string * obj[] -> System.Text.StringBuilder
Public Function AppendFormat (format As String, ParamArray args As Object()) As StringBuilder

Parameters

format
String String String String

A composite format string.

args
Object[]

An array of objects to format.

Returns

A reference to this instance with format appended. Each format item in format is replaced by the string representation of the corresponding object argument.

Exceptions

format is invalid.

-or-

The index of a format item is less than 0 (zero), or greater than or equal to the length of the args array.

Examples

The following example demonstrates the AppendFormat method.

using namespace System;
using namespace System::Text;
using namespace System::Globalization;
void Show( StringBuilder^ sbs )
{
   Console::WriteLine( sbs );
   sbs->Length = 0;
}

int main()
{
   StringBuilder^ sb = gcnew StringBuilder;
   int var1 = 111;
   float var2 = 2.22F;
   String^ var3 = "abcd";
   array<Object^>^var4 = {3,4.4,(Char)'X'};
   Console::WriteLine();
   Console::WriteLine( "StringBuilder.AppendFormat method:" );
   sb->AppendFormat( "1) {0}", var1 );
   Show( sb );
   sb->AppendFormat( "2) {0}, {1}", var1, var2 );
   Show( sb );
   sb->AppendFormat( "3) {0}, {1}, {2}", var1, var2, var3 );
   Show( sb );
   sb->AppendFormat( "4) {0}, {1}, {2}", var4 );
   Show( sb );
   CultureInfo^ ci = gcnew CultureInfo( "es-ES",true );
   array<Object^>^temp1 = {var2};
   sb->AppendFormat( ci, "5) {0}", temp1 );
   Show( sb );
}

/*
This example produces the following results:

StringBuilder.AppendFormat method:
1) 111
2) 111, 2.22
3) 111, 2.22, abcd
4) 3, 4.4, X
5) 2,22
*/
using System;
using System.Text;
using System.Globalization;

class Sample 
{
    static StringBuilder sb = new StringBuilder();

    public static void Main() 
    {
    int    var1   = 111;
    float  var2   = 2.22F;
    string var3   = "abcd";
    object[] var4 = {3, 4.4, 'X'};

    Console.WriteLine();
    Console.WriteLine("StringBuilder.AppendFormat method:");
    sb.AppendFormat("1) {0}", var1);
    Show(sb);
    sb.AppendFormat("2) {0}, {1}", var1, var2);
    Show(sb);
    sb.AppendFormat("3) {0}, {1}, {2}", var1, var2, var3);
    Show(sb);
    sb.AppendFormat("4) {0}, {1}, {2}", var4);
    Show(sb);
    CultureInfo ci = new CultureInfo("es-ES", true);
    sb.AppendFormat(ci, "5) {0}", var2);
    Show(sb);
    }

    public static void Show(StringBuilder sbs)
    {
    Console.WriteLine(sbs.ToString());
    sb.Length = 0;
    }
}
/*
This example produces the following results:

StringBuilder.AppendFormat method:
1) 111
2) 111, 2.22
3) 111, 2.22, abcd
4) 3, 4.4, X
5) 2,22
*/
Imports System
Imports System.Text
Imports System.Globalization

Class Sample
   Private Shared sb As New StringBuilder()

   Public Shared Sub Main()
      Dim var1 As Integer = 111
      Dim var2 As Single = 2.22F
      Dim var3 As String = "abcd"
      Dim var4 As Object() =  {3, 4.4, "X"c}
      
      Console.WriteLine()
      Console.WriteLine("StringBuilder.AppendFormat method:")
      sb.AppendFormat("1) {0}", var1)
      Show(sb)
      sb.AppendFormat("2) {0}, {1}", var1, var2)
      Show(sb)
      sb.AppendFormat("3) {0}, {1}, {2}", var1, var2, var3)
      Show(sb)
      sb.AppendFormat("4) {0}, {1}, {2}", var4)
      Show(sb)
      Dim ci As New CultureInfo("es-ES", True)
      sb.AppendFormat(ci, "5) {0}", var2)
      Show(sb)
   End Sub 'Main
   
   Public Shared Sub Show(sbs As StringBuilder)
      Console.WriteLine(sbs.ToString())
      sb.Length = 0
   End Sub 'Show
End Class 'Sample
'
'This example produces the following results:
'
'StringBuilder.AppendFormat method:
'1) 111
'2) 111, 2.22
'3) 111, 2.22, abcd
'4) 3, 4.4, X
'5) 2,22

Remarks

This method uses the composite formatting feature of the .NET Framework to convert the value of an object to its text representation and embed that representation in the current StringBuilder object.

The format parameter consists of zero or more runs of text intermixed with zero or more indexed placeholders, called format items, that correspond to objects in the parameter list of this method. The formatting process replaces each format item with the string representation of the corresponding object.

The syntax of a format item is as follows:

{index[,length][:formatString]}

Elements in square brackets are optional. The following table describes each element.

Element Description
index The zero-based position in the parameter list of the object to be formatted. If the object specified by index is null, the format item is replaced by String.Empty. If there is no parameter in the index position, a FormatException is thrown.
,length The minimum number of characters in the string representation of the parameter. If positive, the parameter is right-aligned; if negative, it is left-aligned.
:formatString A standard or custom format string that is supported by the parameter.

Note

For the standard and custom format strings used with date and time values, see Standard Date and Time Format Strings and Custom Date and Time Format Strings. For the standard and custom format strings used with numeric values, see Standard Numeric Format Strings and Custom Numeric Format Strings. For the standard format strings used with enumerations, see Enumeration Format Strings.

args represents the objects to be formatted. Each format item in format is replaced with the string representation of the corresponding object in args. If the format item includes formatString and the corresponding object in args implements the IFormattable interface, then args[index].ToString(formatString, provider) defines the formatting. Otherwise, args[index].ToString() defines the formatting.

If the string assigned to format is "Thank you for your donation of {0:####} cans of food to our charitable organization." and arg0 is an integer with the value 10, the return value will be "Thank you for your donation of 10 cans of food to our charitable organization."

Notes to Callers

In .NET Core and in the .NET Framework 4.0 and later versions, when you instantiate the StringBuilder object by calling the StringBuilder(Int32, Int32) constructor, both the length and the capacity of the StringBuilder instance can grow beyond the value of its MaxCapacity property. This can occur particularly when you call the Append(String) and AppendFormat(String, Object) methods to append small strings.

See also

AppendFormat(IFormatProvider, String, Object) AppendFormat(IFormatProvider, String, Object) AppendFormat(IFormatProvider, String, Object) AppendFormat(IFormatProvider, String, Object)

Appends the string returned by processing a composite format string, which contains zero or more format items, to this instance. Each format item is replaced by the string representation of a single argument using a specified format provider.

public:
 System::Text::StringBuilder ^ AppendFormat(IFormatProvider ^ provider, System::String ^ format, System::Object ^ arg0);
public System.Text.StringBuilder AppendFormat (IFormatProvider provider, string format, object arg0);
member this.AppendFormat : IFormatProvider * string * obj -> System.Text.StringBuilder
Public Function AppendFormat (provider As IFormatProvider, format As String, arg0 As Object) As StringBuilder

Parameters

provider
IFormatProvider IFormatProvider IFormatProvider IFormatProvider

An object that supplies culture-specific formatting information.

format
String String String String

A composite format string.

arg0
Object Object Object Object

The object to format.

Returns

A reference to this instance after the append operation has completed. After the append operation, this instance contains any data that existed before the operation, suffixed by a copy of format in which any format specification is replaced by the string representation of arg0.

Exceptions

format is invalid.

-or-

The index of a format item is less than 0 (zero), or greater than or equal to one (1).

Examples

The following includes two calls to the AppendFormat(IFormatProvider, String, Object) method. Both use the formatting conventions of the English-Great Britain (en-GB) culture. The first inserts the string representation of a Decimal value currency in a result string. The second inserts a DateTime value in two places in a result string, the first including only the short date string and the second the short time string.

using System;
using System.Globalization;
using System.Text;

public class Example
{
   public static void Main()
   {
      StringBuilder sb = new StringBuilder();
      Decimal value = 16.95m;
      CultureInfo enGB = CultureInfo.CreateSpecificCulture("en-GB");
      DateTime dateToday = DateTime.Now;
      sb.AppendFormat(enGB, "Final Price: {0:C2}", value);
      sb.AppendLine();
      sb.AppendFormat(enGB, "Date and Time: {0:d} at {0:t}", dateToday);
      Console.WriteLine(sb.ToString());
   }
}
// The example displays the following output:
//       Final Price: £16.95
//       Date and Time: 01/10/2014 at 10:22
Imports System.Globalization
Imports System.Text

Module Example
   Public Sub Main()
      Dim sb As New StringBuilder()
      Dim value As Decimal = 16.95d
      Dim enGB As CultureInfo = CultureInfo.CreateSpecificCulture("en-GB")
      Dim dateToday As DateTime = Date.Now
      sb.AppendFormat(enGB, "Final Price: {0:C2}", value)
      sb.AppendLine()
      sb.AppendFormat(enGB, "Date and Time: {0:d} at {0:t}", dateToday)
      Console.WriteLine(sb.ToString())
   End Sub
End Module
' The example displays output like the following:
'       Final Price: £16.95
'       Date and Time: 01/10/2014 at 10:22

Remarks

This method uses the composite formatting feature of the .NET Framework to convert the value of arg0 to its text representation and embed that representation in the current StringBuilder object.

The format parameter consists of zero or more runs of text intermixed with zero or more indexed placeholders, called format items. The index of each format item must be zero (0) since this method includes an argument list with a single argument. The formatting process replaces each format item with the string representation of arg0.

The syntax of a format item is as follows:

{index[,length][:formatString]}

Elements in square brackets are optional. The following table describes each element.

Element Description
index The zero-based position in the parameter list of the object to be formatted. If the object specified by index is null, the format item is replaced by String.Empty. In this case, since the AppendFormat(IFormatProvider, String, Object) method has a single argument in the argument list, the value of index must always be 0. If it is not, a FormatException is thrown.
,length The minimum number of characters in the string representation of the parameter. If positive, the parameter is right-aligned; if negative, it is left-aligned.
:formatString A standard or custom format string that is supported by the parameter.

Note

For the standard and custom format strings used with date and time values, see Standard Date and Time Format Strings and Custom Date and Time Format Strings. For the standard and custom format strings used with numeric values, see Standard Numeric Format Strings and Custom Numeric Format Strings. For the standard format strings used with enumerations, see Enumeration Format Strings.

The provider parameter specifies an IFormatProvider implementation that can provide formatting information for the objects in args. provider can be any of the following:

  • A CultureInfo object that provides culture-specific formatting information.

  • A NumberFormatInfo object that provides culture-specific formatting information for arg0 if it is a numeric value.

  • A DateTimeFormatInfo object that provides culture-specific formatting information for arg0 if it is a date and time value.

  • A custom IFormatProvider implementation that provides formatting information for arg0. Typically, such an implementation also implements the ICustomFormatter interface.

If the provider parameter is null, formatting information is obtained from the current culture.

arg0 represents the object to be formatted. Each format item in format is replaced with the string representation of arg0. If the format item includes formatString and arg0 implements the IFormattable interface, then arg0.ToString(formatString, provider) defines the formatting. Otherwise, arg0.ToString() defines the formatting.

Notes to Callers

In .NET Core and in the .NET Framework 4.0 and later versions, when you instantiate the StringBuilder object by calling the StringBuilder(Int32, Int32) constructor, both the length and the capacity of the StringBuilder instance can grow beyond the value of its MaxCapacity property. This can occur particularly when you call the Append(String) and AppendFormat(String, Object) methods to append small strings.

See also

AppendFormat(IFormatProvider, String, Object[]) AppendFormat(IFormatProvider, String, Object[]) AppendFormat(IFormatProvider, String, Object[]) AppendFormat(IFormatProvider, String, Object[])

Appends the string returned by processing a composite format string, which contains zero or more format items, to this instance. Each format item is replaced by the string representation of a corresponding argument in a parameter array using a specified format provider.

public:
 System::Text::StringBuilder ^ AppendFormat(IFormatProvider ^ provider, System::String ^ format, ... cli::array <System::Object ^> ^ args);
public System.Text.StringBuilder AppendFormat (IFormatProvider provider, string format, params object[] args);
member this.AppendFormat : IFormatProvider * string * obj[] -> System.Text.StringBuilder
Public Function AppendFormat (provider As IFormatProvider, format As String, ParamArray args As Object()) As StringBuilder

Parameters

provider
IFormatProvider IFormatProvider IFormatProvider IFormatProvider

An object that supplies culture-specific formatting information.

format
String String String String

A composite format string.

args
Object[]

An array of objects to format.

Returns

A reference to this instance after the append operation has completed. After the append operation, this instance contains any data that existed before the operation, suffixed by a copy of format where any format specification is replaced by the string representation of the corresponding object argument.

Exceptions

format is invalid.

-or-

The index of a format item is less than 0 (zero), or greater than or equal to the length of the args array.

Examples

The following example demonstrates the AppendFormat method.

using namespace System;
using namespace System::Text;
using namespace System::Globalization;
void Show( StringBuilder^ sbs )
{
   Console::WriteLine( sbs );
   sbs->Length = 0;
}

int main()
{
   StringBuilder^ sb = gcnew StringBuilder;
   int var1 = 111;
   float var2 = 2.22F;
   String^ var3 = "abcd";
   array<Object^>^var4 = {3,4.4,(Char)'X'};
   Console::WriteLine();
   Console::WriteLine( "StringBuilder.AppendFormat method:" );
   sb->AppendFormat( "1) {0}", var1 );
   Show( sb );
   sb->AppendFormat( "2) {0}, {1}", var1, var2 );
   Show( sb );
   sb->AppendFormat( "3) {0}, {1}, {2}", var1, var2, var3 );
   Show( sb );
   sb->AppendFormat( "4) {0}, {1}, {2}", var4 );
   Show( sb );
   CultureInfo^ ci = gcnew CultureInfo( "es-ES",true );
   array<Object^>^temp1 = {var2};
   sb->AppendFormat( ci, "5) {0}", temp1 );
   Show( sb );
}

/*
This example produces the following results:

StringBuilder.AppendFormat method:
1) 111
2) 111, 2.22
3) 111, 2.22, abcd
4) 3, 4.4, X
5) 2,22
*/
using System;
using System.Text;
using System.Globalization;

class Sample 
{
    static StringBuilder sb = new StringBuilder();

    public static void Main() 
    {
    int    var1   = 111;
    float  var2   = 2.22F;
    string var3   = "abcd";
    object[] var4 = {3, 4.4, 'X'};

    Console.WriteLine();
    Console.WriteLine("StringBuilder.AppendFormat method:");
    sb.AppendFormat("1) {0}", var1);
    Show(sb);
    sb.AppendFormat("2) {0}, {1}", var1, var2);
    Show(sb);
    sb.AppendFormat("3) {0}, {1}, {2}", var1, var2, var3);
    Show(sb);
    sb.AppendFormat("4) {0}, {1}, {2}", var4);
    Show(sb);
    CultureInfo ci = new CultureInfo("es-ES", true);
    sb.AppendFormat(ci, "5) {0}", var2);
    Show(sb);
    }

    public static void Show(StringBuilder sbs)
    {
    Console.WriteLine(sbs.ToString());
    sb.Length = 0;
    }
}
/*
This example produces the following results:

StringBuilder.AppendFormat method:
1) 111
2) 111, 2.22
3) 111, 2.22, abcd
4) 3, 4.4, X
5) 2,22
*/
Imports System
Imports System.Text
Imports System.Globalization

Class Sample
   Private Shared sb As New StringBuilder()

   Public Shared Sub Main()
      Dim var1 As Integer = 111
      Dim var2 As Single = 2.22F
      Dim var3 As String = "abcd"
      Dim var4 As Object() =  {3, 4.4, "X"c}
      
      Console.WriteLine()
      Console.WriteLine("StringBuilder.AppendFormat method:")
      sb.AppendFormat("1) {0}", var1)
      Show(sb)
      sb.AppendFormat("2) {0}, {1}", var1, var2)
      Show(sb)
      sb.AppendFormat("3) {0}, {1}, {2}", var1, var2, var3)
      Show(sb)
      sb.AppendFormat("4) {0}, {1}, {2}", var4)
      Show(sb)
      Dim ci As New CultureInfo("es-ES", True)
      sb.AppendFormat(ci, "5) {0}", var2)
      Show(sb)
   End Sub 'Main
   
   Public Shared Sub Show(sbs As StringBuilder)
      Console.WriteLine(sbs.ToString())
      sb.Length = 0
   End Sub 'Show
End Class 'Sample
'
'This example produces the following results:
'
'StringBuilder.AppendFormat method:
'1) 111
'2) 111, 2.22
'3) 111, 2.22, abcd
'4) 3, 4.4, X
'5) 2,22

The following example defines a custom IFormatProvider implementation named CustomerFormatter that formats a 10-digit customer number with hyphens after the fourth and seventh digits. It is passed to the StringBuilder.AppendFormat(IFormatProvider, String, Object[]) method to create a string that includes the formatted customer number and customer name.

using System;
using System.Text;

public class Customer
{
   private string custName;
   private int custNumber;
   
   public Customer(string name, int number)
   {
      this.custName = name;
      this.custNumber = number;
   }
   
   public string Name
   {
      get { return this.custName; }
   }
   
   public int CustomerNumber
   {
      get { return this.custNumber; }
   }
}

public class CustomerNumberFormatter : IFormatProvider, ICustomFormatter
{   
   public object GetFormat(Type formatType)
   {
      if (formatType == typeof(ICustomFormatter))
         return this;
      return null;
   }
   
   public string Format(string format, object arg, IFormatProvider provider)
   {
      if (arg is Int32)
      {
         string custNumber = ((int) arg).ToString("D10");
         return custNumber.Substring(0, 4) + "-" + custNumber.Substring(4, 3) + 
                "-" + custNumber.Substring(7, 3);
      }
      else
      {
         return null;
      }
   }                   
}

public class Example
{
   public static void Main()
   {
      Customer customer = new Customer("A Plus Software", 903654);
      StringBuilder sb = new StringBuilder();
      sb.AppendFormat(new CustomerNumberFormatter(), "{0}: {1}", 
                      customer.CustomerNumber, customer.Name);
      Console.WriteLine(sb.ToString());
   }
}
// The example displays the following output:
//      0000-903-654: A Plus Software
Imports System.Text

Public Class Customer
   Private custName As String
   Private custNumber As Integer
   
   Public Sub New(name As String, number As Integer)
      custName = name
      custNumber = number
   End Sub
   
   Public ReadOnly Property Name As String
      Get
         Return Me.custName
      End Get
   End Property
   
   Public ReadOnly Property CustomerNumber As Integer
      Get
         Return Me.custNumber
      End Get
   End Property
End Class

Public Class CustomerNumberFormatter 
   Implements IFormatProvider, ICustomFormatter
   
   Public Function GetFormat(formatType As Type) As Object _
                   Implements IFormatProvider.GetFormat
      If formatType Is GetType(ICustomFormatter) Then
         Return Me
      End If
      Return Nothing
   End Function
   
   Public Function Format(fmt As String, arg As Object, provider As IFormatProvider) As String _
                   Implements ICustomFormatter.Format
      If typeof arg Is Int32 Then
         Dim custNumber As String = CInt(arg).ToString("D10")
         Return custNumber.Substring(0, 4) + "-" + custNumber.SubString(4, 3) + _
                "-" + custNumber.Substring(7, 3)
      Else
         Return Nothing
      End If
   End Function                   
End Class

Module Example
   Public Sub Main()
      Dim customer As New Customer("A Plus Software", 903654)
      Dim sb As New StringBuilder()
      sb.AppendFormat(New CustomerNumberFormatter, "{0}: {1}", _
                      customer.CustomerNumber, customer.Name)
      Console.WriteLine(sb.ToString())
   End Sub
End Module
' The example displays the following output:
'      0000-903-654: A Plus Software

Remarks

This method uses the composite formatting feature of the .NET Framework to convert the value of an object to its text representation and embed that representation in the current StringBuilder object.

The format parameter consists of zero or more runs of text intermixed with zero or more indexed placeholders, called format items, that correspond to objects in the parameter list of this method. The formatting process replaces each format item with the string representation of the corresponding object.

The syntax of a format item is as follows:

{index[,length][:formatString]}

Elements in square brackets are optional. The following table describes each element.

Element Description
index The zero-based position in the parameter list of the object to be formatted. If the object specified by index is null, the format item is replaced by String.Empty. If there is no parameter in the index position, a FormatException is thrown.
,length The minimum number of characters in the string representation of the parameter. If positive, the parameter is right-aligned; if negative, it is left-aligned.
:formatString A standard or custom format string that is supported by the parameter.

Note

For the standard and custom format strings used with date and time values, see Standard Date and Time Format Strings and Custom Date and Time Format Strings. For the standard and custom format strings used with numeric values, see Standard Numeric Format Strings and Custom Numeric Format Strings. For the standard format strings used with enumerations, see Enumeration Format Strings.

The provider parameter specifies an IFormatProvider implementation that can provide formatting information for the objects in args. provider can be any of the following:

If the provider parameter is null, format provider information is obtained from the current culture.

args represents the objects to be formatted. Each format item in format is replaced with the string representation of the corresponding object in args. If the format item includes formatString and the corresponding object in args implements the IFormattable interface, then args[index].ToString(formatString, provider) defines the formatting. Otherwise, args[index].ToString() defines the formatting.

Notes to Callers

In .NET Core and in the .NET Framework 4.0 and later versions, when you instantiate the StringBuilder object by calling the StringBuilder(Int32, Int32) constructor, both the length and the capacity of the StringBuilder instance can grow beyond the value of its MaxCapacity property. This can occur particularly when you call the Append(String) and AppendFormat(String, Object) methods to append small strings.

See also

AppendFormat(String, Object, Object) AppendFormat(String, Object, Object) AppendFormat(String, Object, Object) AppendFormat(String, Object, Object)

Appends the string returned by processing a composite format string, which contains zero or more format items, to this instance. Each format item is replaced by the string representation of either of two arguments.

public:
 System::Text::StringBuilder ^ AppendFormat(System::String ^ format, System::Object ^ arg0, System::Object ^ arg1);
public System.Text.StringBuilder AppendFormat (string format, object arg0, object arg1);
member this.AppendFormat : string * obj * obj -> System.Text.StringBuilder
Public Function AppendFormat (format As String, arg0 As Object, arg1 As Object) As StringBuilder

Parameters

format
String String String String

A composite format string.

arg0
Object Object Object Object

The first object to format.

arg1
Object Object Object Object

The second object to format.

Returns

A reference to this instance with format appended. Each format item in format is replaced by the string representation of the corresponding object argument.

Exceptions

format is invalid.

-or-

The index of a format item is less than 0 (zero), or greater than or equal to 2.

Examples

The following example demonstrates the AppendFormat method.

using namespace System;
using namespace System::Text;
using namespace System::Globalization;
void Show( StringBuilder^ sbs )
{
   Console::WriteLine( sbs );
   sbs->Length = 0;
}

int main()
{
   StringBuilder^ sb = gcnew StringBuilder;
   int var1 = 111;
   float var2 = 2.22F;
   String^ var3 = "abcd";
   array<Object^>^var4 = {3,4.4,(Char)'X'};
   Console::WriteLine();
   Console::WriteLine( "StringBuilder.AppendFormat method:" );
   sb->AppendFormat( "1) {0}", var1 );
   Show( sb );
   sb->AppendFormat( "2) {0}, {1}", var1, var2 );
   Show( sb );
   sb->AppendFormat( "3) {0}, {1}, {2}", var1, var2, var3 );
   Show( sb );
   sb->AppendFormat( "4) {0}, {1}, {2}", var4 );
   Show( sb );
   CultureInfo^ ci = gcnew CultureInfo( "es-ES",true );
   array<Object^>^temp1 = {var2};
   sb->AppendFormat( ci, "5) {0}", temp1 );
   Show( sb );
}

/*
This example produces the following results:

StringBuilder.AppendFormat method:
1) 111
2) 111, 2.22
3) 111, 2.22, abcd
4) 3, 4.4, X
5) 2,22
*/
using System;
using System.Text;
using System.Globalization;

class Sample 
{
    static StringBuilder sb = new StringBuilder();

    public static void Main() 
    {
    int    var1   = 111;
    float  var2   = 2.22F;
    string var3   = "abcd";
    object[] var4 = {3, 4.4, 'X'};

    Console.WriteLine();
    Console.WriteLine("StringBuilder.AppendFormat method:");
    sb.AppendFormat("1) {0}", var1);
    Show(sb);
    sb.AppendFormat("2) {0}, {1}", var1, var2);
    Show(sb);
    sb.AppendFormat("3) {0}, {1}, {2}", var1, var2, var3);
    Show(sb);
    sb.AppendFormat("4) {0}, {1}, {2}", var4);
    Show(sb);
    CultureInfo ci = new CultureInfo("es-ES", true);
    sb.AppendFormat(ci, "5) {0}", var2);
    Show(sb);
    }

    public static void Show(StringBuilder sbs)
    {
    Console.WriteLine(sbs.ToString());
    sb.Length = 0;
    }
}
/*
This example produces the following results:

StringBuilder.AppendFormat method:
1) 111
2) 111, 2.22
3) 111, 2.22, abcd
4) 3, 4.4, X
5) 2,22
*/
Imports System
Imports System.Text
Imports System.Globalization

Class Sample
   Private Shared sb As New StringBuilder()

   Public Shared Sub Main()
      Dim var1 As Integer = 111
      Dim var2 As Single = 2.22F
      Dim var3 As String = "abcd"
      Dim var4 As Object() =  {3, 4.4, "X"c}
      
      Console.WriteLine()
      Console.WriteLine("StringBuilder.AppendFormat method:")
      sb.AppendFormat("1) {0}", var1)
      Show(sb)
      sb.AppendFormat("2) {0}, {1}", var1, var2)
      Show(sb)
      sb.AppendFormat("3) {0}, {1}, {2}", var1, var2, var3)
      Show(sb)
      sb.AppendFormat("4) {0}, {1}, {2}", var4)
      Show(sb)
      Dim ci As New CultureInfo("es-ES", True)
      sb.AppendFormat(ci, "5) {0}", var2)
      Show(sb)
   End Sub 'Main
   
   Public Shared Sub Show(sbs As StringBuilder)
      Console.WriteLine(sbs.ToString())
      sb.Length = 0
   End Sub 'Show
End Class 'Sample
'
'This example produces the following results:
'
'StringBuilder.AppendFormat method:
'1) 111
'2) 111, 2.22
'3) 111, 2.22, abcd
'4) 3, 4.4, X
'5) 2,22

Remarks

This method uses the composite formatting feature of the .NET Framework to convert the value of an object to its text representation and embed that representation in the current StringBuilder object.

The format parameter consists of zero or more runs of text intermixed with zero or more indexed placeholders, called format items, that correspond to arg0 and arg1, the two objects in the parameter list of this method. The formatting process replaces each format item with the string representation of the corresponding object.

The syntax of a format item is as follows:

{index[,length][:formatString]}

Elements in square brackets are optional. The following table describes each element.

Element Description
index The zero-based position in the parameter list of the object to be formatted. If the object specified by index is null, the format item is replaced by String.Empty. If there is no parameter in the index position, a FormatException is thrown.
,length The minimum number of characters in the string representation of the parameter. If positive, the parameter is right-aligned; if negative, it is left-aligned.
:formatString A standard or custom format string that is supported by the parameter.

Note

For the standard and custom format strings used with date and time values, see Standard Date and Time Format Strings and Custom Date and Time Format Strings. For the standard and custom format strings used with numeric values, see Standard Numeric Format Strings and Custom Numeric Format Strings. For the standard format strings used with enumerations, see Enumeration Format Strings.

arg0 and arg1 represent the objects to be formatted. Each format item in format is replaced with the string representation of either arg0 or arg1. If the format item includes formatString and the corresponding object implements the IFormattable interface, then argx.ToString(formatString, provider) defines the formatting, where x is the index of the argument. Otherwise, argx.ToString() defines the formatting.

If the string assigned to format is "Thank you for your donation of {0:####} cans of food to our charitable organization." and arg0 is an integer with the value 10, the return value will be "Thank you for your donation of 10 cans of food to our charitable organization."

Notes to Callers

In .NET Core and in the .NET Framework 4.0 and later versions, when you instantiate the StringBuilder object by calling the StringBuilder(Int32, Int32) constructor, both the length and the capacity of the StringBuilder instance can grow beyond the value of its MaxCapacity property. This can occur particularly when you call the Append(String) and AppendFormat(String, Object) methods to append small strings.

See also

AppendFormat(IFormatProvider, String, Object, Object) AppendFormat(IFormatProvider, String, Object, Object) AppendFormat(IFormatProvider, String, Object, Object) AppendFormat(IFormatProvider, String, Object, Object)

Appends the string returned by processing a composite format string, which contains zero or more format items, to this instance. Each format item is replaced by the string representation of either of two arguments using a specified format provider.

public:
 System::Text::StringBuilder ^ AppendFormat(IFormatProvider ^ provider, System::String ^ format, System::Object ^ arg0, System::Object ^ arg1);
public System.Text.StringBuilder AppendFormat (IFormatProvider provider, string format, object arg0, object arg1);
member this.AppendFormat : IFormatProvider * string * obj * obj -> System.Text.StringBuilder
Public Function AppendFormat (provider As IFormatProvider, format As String, arg0 As Object, arg1 As Object) As StringBuilder

Parameters

provider
IFormatProvider IFormatProvider IFormatProvider IFormatProvider

An object that supplies culture-specific formatting information.

format
String String String String

A composite format string.

arg0
Object Object Object Object

The first object to format.

arg1
Object Object Object Object

The second object to format.

Returns

A reference to this instance after the append operation has completed. After the append operation, this instance contains any data that existed before the operation, suffixed by a copy of format where any format specification is replaced by the string representation of the corresponding object argument.

Exceptions

format is invalid.

-or-

The index of a format item is less than 0 (zero), or greater than or equal to 2 (two).

Examples

The following example uses the AppendFormat(IFormatProvider, String, Object, Object) method to display time and temperature data stored in a generic Dictionary<TKey,TValue> object. Note that the format string has three format items, although there are only to objects to format. This is because the first object in the list (a date and time value) is used by two format items: The first format item displays the time, and the second displays the date.

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Text;

public class Example
{
   public static void Main()
   {
      CultureInfo culture = new CultureInfo("en-US");
      StringBuilder sb = new StringBuilder();
      Dictionary<DateTime, Double> temperatureInfo = new Dictionary<DateTime, Double>(); 
      temperatureInfo.Add(new DateTime(2010, 6, 1, 14, 0, 0), 87.46);
      temperatureInfo.Add(new DateTime(2010, 12, 1, 10, 0, 0), 36.81);
      

      sb.AppendLine("Temperature Information:\n");
      foreach (var item in temperatureInfo)
      {
         sb.AppendFormat(culture,
                         "Temperature at {0,8:t} on {0,9:d}: {1,5:N1}°F\n",
                         item.Key, item.Value);
      }
      Console.WriteLine(sb.ToString());
   }
}
// The example displays the following output:
//       Temperature Information:
//       
//       Temperature at  2:00 PM on  6/1/2010:  87.5°F
//       Temperature at 10:00 AM on 12/1/2010:  36.8°F
Imports System.Collections.Generic
Imports System.Globalization
Imports System.Text

Module Example
   Public Sub Main()
      Dim culture As New CultureInfo("en-US")
      Dim sb As New StringBuilder()
      Dim temperatureInfo As New Dictionary(Of Date, Double) 
      temperatureInfo.Add(#6/1/2010 2:00PM#, 87.46)
      temperatureInfo.Add(#12/1/2010 10:00AM#, 36.81)
      
      sb.AppendLine("Temperature Information:").AppendLine()
      For Each item In temperatureInfo
         sb.AppendFormat(culture,
                         "Temperature at {0,8:t} on {0,9:d}: {1,5:N1}°F",
                         item.Key, item.Value).AppendLine()
      Next
      Console.WriteLine(sb.ToString())
   End Sub
End Module
' The example displays the following output:
'       Temperature Information:
'       
'       Temperature at  2:00 PM on  6/1/2010:  87.5°F
'       Temperature at 10:00 AM on 12/1/2010:  36.8°F

Remarks

This method uses the composite formatting feature of the .NET Framework to convert the value of an object to its text representation and embed that representation in the current StringBuilder object.

The format parameter consists of zero or more runs of text intermixed with zero or more indexed placeholders, called format items, that correspond to objects in the parameter list of this method. The formatting process replaces each format item with the string representation of the corresponding object.

The syntax of a format item is as follows:

{index[,length][:formatString]}

Elements in square brackets are optional. The following table describes each element.

Element Description
index The zero-based position in the parameter list of the object to be formatted. If the object specified by index is null, the format item is replaced by String.Empty. If there is no parameter in the index position, a FormatException is thrown.
,length The minimum number of characters in the string representation of the parameter. If positive, the parameter is right-aligned; if negative, it is left-aligned.
:formatString A standard or custom format string that is supported by the parameter.

Note

For the standard and custom format strings used with date and time values, see Standard Date and Time Format Strings and Custom Date and Time Format Strings. For the standard and custom format strings used with numeric values, see Standard Numeric Format Strings and Custom Numeric Format Strings. For the standard format strings used with enumerations, see Enumeration Format Strings.

The provider parameter specifies an IFormatProvider implementation that can provide formatting information for arg0 and arg1. provider can be any of the following:

  • A CultureInfo object that provides culture-specific formatting information.

  • A NumberFormatInfo object that provides culture-specific formatting information for arg0 or arg1 if they are numeric values.

  • A DateTimeFormatInfo object that provides culture-specific formatting information for arg0 or arg1 if they are date and time values.

  • A custom IFormatProvider implementation that provides formatting information for arg0 and arg1. Typically, such an implementation also implements the ICustomFormatter interface.

If the provider parameter is null, format provider information is obtained from the current culture.

arg0 and arg1 represent the objects to be formatted. Each format item in format is replaced with the string representation of the object that has the corresponding index. If the format item includes formatString and the corresponding argument implements the IFormattable interface, then the argument's ToString(formatString, provider) method defines the formatting. Otherwise, the argument's ToString() method defines the formatting.

Notes to Callers

IIn .NET Core and in the .NET Framework 4.0 and later versions, when you instantiate the StringBuilder object by calling the StringBuilder(Int32, Int32) constructor, both the length and the capacity of the StringBuilder instance can grow beyond the value of its MaxCapacity property. This can occur particularly when you call the Append(String) and AppendFormat(String, Object) methods to append small strings.

See also

AppendFormat(String, Object, Object, Object) AppendFormat(String, Object, Object, Object) AppendFormat(String, Object, Object, Object) AppendFormat(String, Object, Object, Object)

Appends the string returned by processing a composite format string, which contains zero or more format items, to this instance. Each format item is replaced by the string representation of either of three arguments.

public:
 System::Text::StringBuilder ^ AppendFormat(System::String ^ format, System::Object ^ arg0, System::Object ^ arg1, System::Object ^ arg2);
public System.Text.StringBuilder AppendFormat (string format, object arg0, object arg1, object arg2);
member this.AppendFormat : string * obj * obj * obj -> System.Text.StringBuilder
Public Function AppendFormat (format As String, arg0 As Object, arg1 As Object, arg2 As Object) As StringBuilder

Parameters

format
String String String String

A composite format string.

arg0
Object Object Object Object

The first object to format.

arg1
Object Object Object Object

The second object to format.

arg2
Object Object Object Object

The third object to format.

Returns

A reference to this instance with format appended. Each format item in format is replaced by the string representation of the corresponding object argument.

Exceptions

format is invalid.

-or-

The index of a format item is less than 0 (zero), or greater than or equal to 3.

Examples

The following example demonstrates the AppendFormat method.

using namespace System;
using namespace System::Text;
using namespace System::Globalization;
void Show( StringBuilder^ sbs )
{
   Console::WriteLine( sbs );
   sbs->Length = 0;
}

int main()
{
   StringBuilder^ sb = gcnew StringBuilder;
   int var1 = 111;
   float var2 = 2.22F;
   String^ var3 = "abcd";
   array<Object^>^var4 = {3,4.4,(Char)'X'};
   Console::WriteLine();
   Console::WriteLine( "StringBuilder.AppendFormat method:" );
   sb->AppendFormat( "1) {0}", var1 );
   Show( sb );
   sb->AppendFormat( "2) {0}, {1}", var1, var2 );
   Show( sb );
   sb->AppendFormat( "3) {0}, {1}, {2}", var1, var2, var3 );
   Show( sb );
   sb->AppendFormat( "4) {0}, {1}, {2}", var4 );
   Show( sb );
   CultureInfo^ ci = gcnew CultureInfo( "es-ES",true );
   array<Object^>^temp1 = {var2};
   sb->AppendFormat( ci, "5) {0}", temp1 );
   Show( sb );
}

/*
This example produces the following results:

StringBuilder.AppendFormat method:
1) 111
2) 111, 2.22
3) 111, 2.22, abcd
4) 3, 4.4, X
5) 2,22
*/
using System;
using System.Text;
using System.Globalization;

class Sample 
{
    static StringBuilder sb = new StringBuilder();

    public static void Main() 
    {
    int    var1   = 111;
    float  var2   = 2.22F;
    string var3   = "abcd";
    object[] var4 = {3, 4.4, 'X'};

    Console.WriteLine();
    Console.WriteLine("StringBuilder.AppendFormat method:");
    sb.AppendFormat("1) {0}", var1);
    Show(sb);
    sb.AppendFormat("2) {0}, {1}", var1, var2);
    Show(sb);
    sb.AppendFormat("3) {0}, {1}, {2}", var1, var2, var3);
    Show(sb);
    sb.AppendFormat("4) {0}, {1}, {2}", var4);
    Show(sb);
    CultureInfo ci = new CultureInfo("es-ES", true);
    sb.AppendFormat(ci, "5) {0}", var2);
    Show(sb);
    }

    public static void Show(StringBuilder sbs)
    {
    Console.WriteLine(sbs.ToString());
    sb.Length = 0;
    }
}
/*
This example produces the following results:

StringBuilder.AppendFormat method:
1) 111
2) 111, 2.22
3) 111, 2.22, abcd
4) 3, 4.4, X
5) 2,22
*/
Imports System
Imports System.Text
Imports System.Globalization

Class Sample
   Private Shared sb As New StringBuilder()

   Public Shared Sub Main()
      Dim var1 As Integer = 111
      Dim var2 As Single = 2.22F
      Dim var3 As String = "abcd"
      Dim var4 As Object() =  {3, 4.4, "X"c}
      
      Console.WriteLine()
      Console.WriteLine("StringBuilder.AppendFormat method:")
      sb.AppendFormat("1) {0}", var1)
      Show(sb)
      sb.AppendFormat("2) {0}, {1}", var1, var2)
      Show(sb)
      sb.AppendFormat("3) {0}, {1}, {2}", var1, var2, var3)
      Show(sb)
      sb.AppendFormat("4) {0}, {1}, {2}", var4)
      Show(sb)
      Dim ci As New CultureInfo("es-ES", True)
      sb.AppendFormat(ci, "5) {0}", var2)
      Show(sb)
   End Sub 'Main
   
   Public Shared Sub Show(sbs As StringBuilder)
      Console.WriteLine(sbs.ToString())
      sb.Length = 0
   End Sub 'Show
End Class 'Sample
'
'This example produces the following results:
'
'StringBuilder.AppendFormat method:
'1) 111
'2) 111, 2.22
'3) 111, 2.22, abcd
'4) 3, 4.4, X
'5) 2,22

Remarks

This method uses the composite formatting feature of the .NET Framework to convert the value of an object to its text representation and embed that representation in the current StringBuilder object.

The format parameter consists of zero or more runs of text intermixed with zero or more indexed placeholders, called format items, that correspond to arg0 through arg2, the objects in the parameter list of this method. The formatting process replaces each format item with the string representation of the corresponding object.

The syntax of a format item is as follows:

{index[,length][:formatString]}

Elements in square brackets are optional. The following table describes each element.

Element Description
index The zero-based position in the parameter list of the object to be formatted. If the object specified by index is null, the format item is replaced by String.Empty. If there is no parameter in the index position, a FormatException is thrown.
,length The minimum number of characters in the string representation of the parameter. If positive, the parameter is right-aligned; if negative, it is left-aligned.
:formatString A standard or custom format string that is supported by the parameter.

Note

For the standard and custom format strings used with date and time values, see Standard Date and Time Format Strings and Custom Date and Time Format Strings. For the standard and custom format strings used with numeric values, see Standard Numeric Format Strings and Custom Numeric Format Strings. For the standard format strings used with enumerations, see Enumeration Format Strings.

arg0, arg1, and arg2 represent the objects to be formatted. Each format item in format is replaced with the string representation of either arg0, arg1, or arg2, depending on the index of the format item. If the format item includes formatString and the corresponding object in args implements the IFormattable interface, then argx.ToString(formatString, null) defines the formatting, where x is the index of the argument. Otherwise, argx.ToString() defines the formatting.

If the string assigned to format is "Thank you for your donation of {0:####} cans of food to our charitable organization." and arg0 is an integer with the value 10, the return value will be "Thank you for your donation of 10 cans of food to our charitable organization."

Notes to Callers

In .NET Core and in the .NET Framework 4.0 and later versions, when you instantiate the StringBuilder object by calling the StringBuilder(Int32, Int32) constructor, both the length and the capacity of the StringBuilder instance can grow beyond the value of its MaxCapacity property. This can occur particularly when you call the Append(String) and AppendFormat(String, Object) methods to append small strings.

See also

Applies to