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Convert.ToDateTime Method (Object, IFormatProvider)

Converts the value of the specified Object to a DateTime using the specified culture-specific formatting information.

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

'Declaration
Public Shared Function ToDateTime ( _
	value As Object, _
	provider As IFormatProvider _
) As DateTime
'Usage
Dim value As Object
Dim provider As IFormatProvider
Dim returnValue As DateTime

returnValue = Convert.ToDateTime(value, provider)
public static DateTime ToDateTime (
	Object value, 
	IFormatProvider provider
)
public static function ToDateTime (
	value : Object, 
	provider : IFormatProvider
) : DateTime
Not applicable.

Parameters

value

An Object that implements the IConvertible interface.

provider

An IFormatProvider interface implementation that supplies culture-specific formatting information.

Return Value

A DateTime equivalent to the value of value. -or- A DateTime equivalent to DateTime.MinValue if value is a null reference (Nothing in Visual Basic).

Exception typeCondition

InvalidCastException

value does not implement IConvertible.

The return value is the result of invoking the IConvertible.ToDateTime method of the underlying type of value.

provider enables the user to specify culture-specific conversion information about the contents of value. For example, if value is a String that represents a date, provider could supply culture-specific information about the notation used to represent that date.

The base types ignore provider; however, it is honored if value is a user-defined type that implements the IConvertible interface.

The following code example defines a class that implements IConvertible and a class that implements IFormatProvider. Objects of the class that implements IConvertible hold an array of Double values. An object of each class is passed to the ToDateTime method. This method calculates an average of the array of Double values, using the object that implements IFormatProvider to determine how to calculate the average. The method returns the sum of this average, taken as seconds, and the current date and time.

' Example of the Convert.ToXXX( Object, IFormatProvider ) methods.
Imports System
Imports System.Collections
Imports Microsoft.VisualBasic

Module IConvertibleProviderDemo

    ' Define the types of averaging available in the class 
    ' implementing IConvertible.
    Enum AverageType as Short
        None = 0
        GeometricMean = 1
        ArithmeticMean = 2
        Median = 3
    End Enum

    ' Pass an instance of this class to methods that require an 
    ' IFormatProvider. The class instance determines the type of 
    ' average to calculate.
    Public Class AverageInfo
        Implements IFormatProvider

        Protected  AvgType      As AverageType

        ' Specify the type of averaging in the constructor.
        Public Sub New( avgType As AverageType )
            Me.AvgType = avgType
        End Sub

        ' This method returns a reference to the containing object 
        ' if an object of AverageInfo type is requested. 
        Public Function GetFormat( argType As Type ) As Object _
            Implements IFormatProvider.GetFormat

            If argType Is GetType( AverageInfo ) Then
                Return Me
            Else
                Return Nothing
            End If
        End Function 

        ' Use this property to set or get the type of averaging.
        Public Property TypeOfAverage( ) As AverageType
            Get
                Return Me.AvgType
            End Get
            Set( ByVal value as AverageType )
                Me.AvgType = value
            End Set
        End Property
    End Class 

    ' This class encapsulates an array of Double values and implements 
    ' the IConvertible interface. Most of the IConvertible methods 
    ' return an average of the array elements in one of three types: 
    ' arithmetic mean, geometric mean, or median. 
    Public Class DataSet
        Implements IConvertible

        Protected data              As ArrayList
        Protected defaultProvider   As AverageInfo
           
        ' Construct the object and add an initial list of values.
        ' Create a default format provider.
        Public Sub New( ParamArray values( ) As Double )
            data = New ArrayList( values )
            defaultProvider = New AverageInfo( _
                AverageType.ArithmeticMean )  
        End Sub
           
        ' Add additional values with this method.
        Public Function Add( value As Double ) As Integer
            data.Add( value )
            Return data.Count
        End Function
           
        ' Get, set, and add values with this indexer property.
        Default Public Property Item(index As Integer) As Double
            Get
                If index >= 0 AndAlso index < data.Count Then
                    Return System.Convert.ToDouble( data( index ) )
                Else
                    Throw New InvalidOperationException( _
                        "[DataSet.get] Index out of range." )
                End If
            End Get
            Set
                If index >= 0 AndAlso index < data.Count Then
                    data( index ) = value
                 
                ElseIf index = data.Count Then
                    data.Add( value )
                Else
                    Throw New InvalidOperationException( _
                        "[DataSet.set] Index out of range." )
                End If
            End Set
        End Property
          
        ' This property returns the number of elements in the object.
        Public ReadOnly Property Count( ) As Integer
            Get
                Return data.Count
            End Get
        End Property

        ' This method calculates the average of the object's elements.
        Protected Function Average( ByVal avgType As AverageType ) As Double

            Dim SumProd As Double 
            Dim Index   As Integer

            If data.Count = 0 Then Return 0.0

            Select Case avgType
                
                Case AverageType.GeometricMean

                    SumProd = 1.0
                    For Index = 0 To data.Count - 1
                        SumProd *= data( Index )
                    Next Index
                    
                    ' This calculation will not fail with negative 
                    ' elements.
                    Return Math.Sign( SumProd ) * Math.Pow( _
                        Math.Abs( SumProd ), 1.0 / data.Count )

                Case AverageType.ArithmeticMean

                    SumProd = 0.0
                    For Index = 0 To data.Count - 1
                        SumProd += data( Index )
                    Next Index

                    Return SumProd / data.Count 

                Case AverageType.Median

                    If data.Count Mod 2 = 0 Then
                        Return ( data( data.Count \ 2 ) + _
                            data( data.Count \ 2 - 1 ) ) / 2.0
                    Else
                        Return data( data.Count \ 2 ) 
                    End If
            End Select
        End Function

        ' Get the AverageInfo object from the caller's format 
        ' provider, or use the local default.
        Protected Function GetAverageInfo( _
            provider As IFormatProvider ) As AverageInfo

            Dim avgInfo As AverageInfo = Nothing

            If Not provider Is Nothing Then
                avgInfo = provider.GetFormat( GetType( AverageInfo ) )
            End If

            Return IIf( avgInfo Is Nothing, defaultProvider, avgInfo )
            
        End Function           

        ' Calculate the average and limit the range.
        Protected Function CalcNLimitAverage( min As Double, _
            max As Double, provider as IFormatProvider ) As Double

            ' Get the format provider and calculate the average.
            Dim avgInfo As AverageInfo = GetAverageInfo( provider )
            Dim avg As Double = Average( avgInfo.TypeOfAverage )

            ' Limit the range, based on the minimum and maximum values 
            ' for the type.
            Return IIf( avg > max, max, IIf( avg < min, min, avg ) )

        End Function

        ' The following elements are required by IConvertible.

        ' None of these conversion functions throw exceptions. When
        ' the data is out of range for the type, the appropriate
        ' MinValue or MaxValue is used.
        Public Function GetTypeCode( ) As TypeCode _
            Implements IConvertible.GetTypeCode
            Return TypeCode.Object
        End Function

        Function ToBoolean( ByVal provider As IFormatProvider ) As _
            Boolean Implements IConvertible.ToBoolean

            ' ToBoolean is false if the dataset is empty.
            If data.Count <= 0 Then
                Return False

            ' For median averaging, ToBoolean is true if any 
            ' non-discarded elements are nonzero.
            ElseIf AverageType.Median = _
                GetAverageInfo( provider ).TypeOfAverage Then

                If data.Count Mod 2 = 0 Then
                    Return ( data( data.Count \ 2 ) <> 0.0 Or _
                        data( data.Count \ 2 - 1 ) <> 0.0 )
                Else
                    Return data( data.Count \ 2 ) <> 0.0
                End If

            ' For arithmetic or geometric mean averaging, ToBoolean is 
            ' true if any element of the dataset is nonzero.  
            Else
                Dim Index As Integer
                For Index = 0 To data.Count - 1
                    If data( Index ) <> 0.0 Then Return True
                Next Index
                Return False
            End If
        End Function

        Function ToByte( ByVal provider As IFormatProvider ) As Byte _
            Implements IConvertible.ToByte
            Return Convert.ToByte( CalcNLimitAverage( _
                Byte.MinValue, Byte.MaxValue, provider ) )
        End Function

        Function ToChar( ByVal provider As IFormatProvider ) As Char _
            Implements IConvertible.ToChar
            Return Convert.ToChar( Convert.ToUInt16( _
                CalcNLimitAverage( 0.0, &HFFFF, provider ) ) )
        End Function

        ' Convert to DateTime by adding the calculated average as 
        ' seconds to the current date and time. A valid DateTime is 
        ' always returned.
        Function ToDateTime( ByVal provider As IFormatProvider ) As _
            DateTime Implements IConvertible.ToDateTime
            Dim seconds As Double = Average( _
                GetAverageInfo( provider ).TypeOfAverage )
            Try
                Return DateTime.Now.AddSeconds( seconds )
            Catch ex As ArgumentOutOfRangeException 
                Return IIf( seconds < 0.0, DateTime.MinValue, _
                    DateTime.MaxValue )
            End Try
        End Function

        Function ToDecimal( ByVal provider As IFormatProvider ) As _
            Decimal Implements IConvertible.ToDecimal

            ' The Double conversion rounds Decimal.MinValue and
            ' Decimal.MaxValue to invalid Decimal values, so the 
            ' following limits must be used.
            Return Convert.ToDecimal( CalcNLimitAverage( _
                -79228162514264330000000000000.0, _
                79228162514264330000000000000.0, provider ) )
        End Function

        Function ToDouble( ByVal provider As IFormatProvider) As _
            Double Implements IConvertible.ToDouble
            Return Average( GetAverageInfo( provider ).TypeOfAverage )
        End Function

        Function ToInt16( ByVal provider As IFormatProvider ) As _
            Short Implements IConvertible.ToInt16
            Return Convert.ToInt16( CalcNLimitAverage( _
                Int16.MinValue, Int16.MaxValue, provider ) )
        End Function

        Function ToInt32( ByVal provider As IFormatProvider ) As _
            Integer Implements IConvertible.ToInt32
            Return Convert.ToInt32( CalcNLimitAverage( _
                Int32.MinValue, Int32.MaxValue, provider ) )
        End Function

        Function ToInt64( ByVal provider As IFormatProvider ) As Long _
            Implements IConvertible.ToInt64

            ' The Double conversion rounds Int64.MinValue and 
            ' Int64.MaxValue to invalid Long values, so the following 
            ' limits must be used.
            Return Convert.ToInt64( CalcNLimitAverage( _
                -9223372036854775000, 9223372036854775000, provider ) )
        End Function

        Function ToSByte( ByVal provider As IFormatProvider ) As _
            SByte Implements IConvertible.ToSByte

            ' SByte.MinValue and SByte.MaxValue are not defined in
            ' Visual Basic.
            Return Convert.ToSByte( CalcNLimitAverage( _
                -128, 127, provider ) )
        End Function

        Function ToSingle( ByVal provider As IFormatProvider ) As _
            Single Implements IConvertible.ToSingle
            Return Convert.ToSingle( CalcNLimitAverage( _
                Single.MinValue, Single.MaxValue, provider ) )
        End Function

        Function ToUInt16( ByVal provider As IFormatProvider ) As _
            UInt16 Implements IConvertible.ToUInt16

            ' UInt16.MinValue and UInt16.MaxValue are not defined in 
            ' Visual Basic.
            Return Convert.ToUInt16( CalcNLimitAverage( _
                0, &HFFFF, provider ) )
        End Function

        Function ToUInt32( ByVal provider As IFormatProvider ) As _
            UInt32 Implements IConvertible.ToUInt32

            ' UInt32.MinValue and UInt32.MaxValue are not defined in 
            ' Visual Basic.
            Return Convert.ToUInt32( CalcNLimitAverage( _
                0, 4294967295, provider ) )
        End Function

        Function ToUInt64( ByVal provider As IFormatProvider ) As _
            UInt64 Implements IConvertible.ToUInt64

            ' UInt64.MinValue and UInt64.MaxValue are not defined in 
            ' Visual Basic. The Double conversion would have rounded 
            ' UInt64.MaxValue, so the following limit must be used.
            Return Convert.ToUInt64( CalcNLimitAverage( _
                0, 18446744073709550000.0, provider ) )
        End Function

        Function ToType( ByVal conversionType As Type, _
            ByVal provider As IFormatProvider) As Object _
            Implements IConvertible.ToType
            Return Convert.ChangeType( Average( GetAverageInfo( _
                provider ).TypeOfAverage ), conversionType )
        End Function

        Overloads Function ToString( ByVal provider As IFormatProvider _
            ) As String Implements IConvertible.ToString
            Dim avgType as AverageType = _
                GetAverageInfo( provider ).TypeOfAverage
            Return String.Format( "( {0}: {1:G10} )", avgType, _
                Average( avgType ) )
        End Function
    End Class
   
    ' Display a DataSet with three different format providers.
    Sub DisplayDataSet( ds As DataSet )

        Dim fmt    As String      = "{0,-12}{1,20}{2,20}{3,20}"
        Dim median As AverageInfo = New AverageInfo( AverageType.Median )
        Dim geMean As AverageInfo = _
            New AverageInfo( AverageType.GeometricMean )
        Dim iX     As Integer

        ' Display the dataset elements.
        If ds.Count > 0 Then
            Console.Write( vbCrLf & "DataSet: [{0}", ds( 0 ) )
            For iX = 1 To ds.Count - 1
                Console.Write( ", {0}", ds( iX ) )
            Next iX
            Console.WriteLine( "]" & vbCrLf )
        End If

        Console.WriteLine( fmt, "Convert.", "Default", _
            "Geometric Mean", "Median" )
        Console.WriteLine( fmt, "--------", "-------", _
            "--------------", "------" )
        Console.WriteLine( fmt, "ToBoolean", _
            Convert.ToBoolean( ds, Nothing ), _
            Convert.ToBoolean( ds, geMean ), _
            Convert.ToBoolean( ds, median ) )
        Console.WriteLine( fmt, "ToByte", _
            Convert.ToByte( ds, Nothing ), _
            Convert.ToByte( ds, geMean ), _
            Convert.ToByte( ds, median ) )
        Console.WriteLine( fmt, "ToChar", _
            Convert.ToChar( ds, Nothing ), _
            Convert.ToChar( ds, geMean ), _
            Convert.ToChar( ds, median ) )
        Console.WriteLine( "{0,-12}{1,20:yyyy-MM-dd HH:mm:ss}" & _
            "{2,20:yyyy-MM-dd HH:mm:ss}{3,20:yyyy-MM-dd HH:mm:ss}", _
            "ToDateTime", Convert.ToDateTime( ds, Nothing ), _
            Convert.ToDateTime( ds, geMean ), _
            Convert.ToDateTime( ds, median ) )
        Console.WriteLine( fmt, "ToDecimal", _
            Convert.ToDecimal( ds, Nothing ), _
            Convert.ToDecimal( ds, geMean ), _
            Convert.ToDecimal( ds, median ) )
        Console.WriteLine( fmt, "ToDouble", _
            Convert.ToDouble( ds, Nothing ), _
            Convert.ToDouble( ds, geMean ), _
            Convert.ToDouble( ds, median ) )
        Console.WriteLine( fmt, "ToInt16", _
            Convert.ToInt16( ds, Nothing ), _
            Convert.ToInt16( ds, geMean ), _
            Convert.ToInt16( ds, median ) )
        Console.WriteLine( fmt, "ToInt32", _
            Convert.ToInt32( ds, Nothing ), _
            Convert.ToInt32( ds, geMean ), _
            Convert.ToInt32( ds, median ) )
        Console.WriteLine( fmt, "ToInt64", _
            Convert.ToInt64( ds, Nothing ), _
            Convert.ToInt64( ds, geMean ), _
            Convert.ToInt64( ds, median ) )
        Console.WriteLine( fmt, "ToSByte", _
            Convert.ToSByte( ds, Nothing ), _
            Convert.ToSByte( ds, geMean ), _
            Convert.ToSByte( ds, median ) )
        Console.WriteLine( fmt, "ToSingle", _
            Convert.ToSingle( ds, Nothing ), _
            Convert.ToSingle( ds, geMean ), _
            Convert.ToSingle( ds, median ) )
        Console.WriteLine( fmt, "ToUInt16", _
            Convert.ToUInt16( ds, Nothing ), _
            Convert.ToUInt16( ds, geMean ), _
            Convert.ToUInt16( ds, median ) )
        Console.WriteLine( fmt, "ToUInt32", _
            Convert.ToUInt32( ds, Nothing ), _
            Convert.ToUInt32( ds, geMean ), _
            Convert.ToUInt32( ds, median ) )
        Console.WriteLine( fmt, "ToUInt64", _
            Convert.ToUInt64( ds, Nothing ), _
            Convert.ToUInt64( ds, geMean ), _
            Convert.ToUInt64( ds, median ) )
    End Sub
   
    Sub Main( )
        Console.WriteLine( _
            "This example of the Convert.ToXXX( Object, " & _
            "IFormatProvider ) methods " & vbCrLf & "generates " & _
            "the following output. The example displays the " & _
            "values " & vbCrLf & "returned by the methods, " & _
            "using several IFormatProvider objects." & vbCrLf )
          
        Dim ds1 As New DataSet( 10.5, 22.2, 45.9, 88.7, 156.05, 297.6 )
        DisplayDataSet( ds1 )
          
        Dim ds2 As New DataSet( _
            359999.95, 425000, 499999.5, 775000, 1695000 )
        DisplayDataSet( ds2 )
    End Sub 
End Module 

' This example of the Convert.ToXXX( Object, IFormatProvider ) methods
' generates the following output. The example displays the values
' returned by the methods, using several IFormatProvider objects.
' 
' DataSet: [10.5, 22.2, 45.9, 88.7, 156.05, 297.6]
' 
' Convert.                 Default      Geometric Mean              Median
' --------                 -------      --------------              ------
' ToBoolean                   True                True                True
' ToByte                       103                  59                  67
' ToChar                         g                   ;                   C
' ToDateTime   2003-05-13 14:52:53 2003-05-13 14:52:09 2003-05-13 14:52:17
' ToDecimal       103.491666666667    59.4332135445164                67.3
' ToDouble        103.491666666667    59.4332135445164                67.3
' ToInt16                      103                  59                  67
' ToInt32                      103                  59                  67
' ToInt64                      103                  59                  67
' ToSByte                      103                  59                  67
' ToSingle                103.4917            59.43321                67.3
' ToUInt16                     103                  59                  67
' ToUInt32                     103                  59                  67
' ToUInt64                     103                  59                  67
' 
' DataSet: [359999.95, 425000, 499999.5, 775000, 1695000]
' 
' Convert.                 Default      Geometric Mean              Median
' --------                 -------      --------------              ------
' ToBoolean                   True                True                True
' ToByte                       255                 255                 255
' ToChar                         ?                   ?                   ?
' ToDateTime   2003-05-22 07:27:49 2003-05-20 22:17:27 2003-05-19 09:44:29
' ToDecimal              750999.89    631577.237188435            499999.5
' ToDouble               750999.89    631577.237188435            499999.5
' ToInt16                    32767               32767               32767
' ToInt32                   751000              631577              500000
' ToInt64                   751000              631577              500000
' ToSByte                      127                 127                 127
' ToSingle                750999.9            631577.3            499999.5
' ToUInt16                   65535               65535               65535
' ToUInt32                  751000              631577              500000
' ToUInt64                  751000              631577              500000

// Example of the Convert.ToXXX( object, IFormatProvider ) methods.
import System.* ;
import System.Collections.* ;

// Define the types of averaging available in the class 
// implementing IConvertible.
public class AverageType
{
    public static final short None = 0;
    public static final short GeometricMean = 1;
    public static final short ArithmeticMean = 2;
    public static final short Median = 3;
} //AverageType
// Pass an instance of this class to methods that require an 
// IFormatProvider. The class instance determines the type of 
// average to calculate.
public class AverageInfo implements IFormatProvider
{
    protected int avgType;   

    // Specify the type of averaging in the constructor.
    public AverageInfo(int  avgType) 
    {
        this.avgType = avgType;
    } //AverageInfo

    // This method returns a reference to the containing object 
    // if an object of AverageInfo type is requested. 
    public Object GetFormat(Type argType) 
    {
        if ( argType == AverageInfo.class.ToType()) {
            return this ;
        }
        else {
            return null ;
        }
    } //GetFormat 

    // Use this property to set or get the type of averaging.
    /** @property 
     */
    public int get_TypeOfAverage()
    {
        return this.avgType ;
    } //get_TypeOfAverage

    /** @property 
     */
    public void set_TypeOfAverage(int value )
    {
        this.avgType = value;
    } //set_TypeOfAverage
} //AverageInfo


// This class encapsulates an array of double values and implements 
// the IConvertible interface. Most of the IConvertible methods 
// return an average of the array elements in one of three types: 
// arithmetic mean, geometric mean, or median. 
public class DataSet implements IConvertible
{
    protected ArrayList data;
    protected AverageInfo defaultProvider;

    // Construct the object and add an initial list of values.
    // Create a default format provider.
    public DataSet(double values[])
    {
        data = new ArrayList(values);
        defaultProvider = new AverageInfo(AverageType.ArithmeticMean);
    } //DataSet

    // Add additional values with this method.
    public int Add(double value) 
    {
        data.Add(new Double(value));
        return data.get_Count() ;
    } //Add

    // Get, set, and add values with this indexer property.
    /** @property 
     */
    public double get_Item(int index) throws InvalidOperationException
    {
        if ((index >= 0) && (index < data.get_Count())) {
            return Convert.ToDouble((data.get_Item(index))) ;
        }
        else {
            throw new InvalidOperationException(
                "[DataSet.get] Index out of range.") ;
        }
    } //get_Item

    /** @property 
     */
    public void set_Item(int index, double value) 
        throws InvalidOperationException
    {
        if ((index >= 0) && (index < data.get_Count())) {
            data.set_Item( index ,(Int64) value );
        }
        else {
            if ( index == data.get_Count()  ) {
                data.Add((Int64)value);
            }
            else {            
                throw new InvalidOperationException(
                    "[DataSet.set] Index out of range.") ;
            }
        }
    } //set_Item

    // This property returns the number of elements in the object.
    /** @property 
     */
    public int get_Count()
    {
        return data.get_Count() ;
    } //get_Count

    // This method calculates the average of the object's elements.
    protected double Average(int avgType)
    {
        double SumProd;

        if ( data.get_Count() == 0  ) {
            return 0.0 ;
        }

        if (avgType == AverageType.GeometricMean) { 
            SumProd = 1.0;
            for(int index =0 ; index < data.get_Count(); index++) {        
                SumProd = SumProd * Convert.ToDouble((data.get_Item(index)));
            }  
            // This calculation will not fail with negative 
            // elements.
            return System.Math.Sign(SumProd) 
                * System.Math.Pow(System.Math.Abs(SumProd), 
                1.0 / data.get_Count());
        }
        else if (avgType == AverageType.ArithmeticMean ) { 
            SumProd = 0.0;
            for(int Index=0; Index < data.get_Count(); Index++) {
                SumProd += Convert.ToDouble((data.get_Item(Index)));
            }  
            return SumProd / data.get_Count() ;
        }
        else if (avgType == AverageType.Median ) {
            if ( (data.get_Count() % 2) == 0 ) {
                return ((Convert.ToDouble(data.get_Item(data.get_Count() / 2))
                    + Convert.ToDouble(data.get_Item(data.get_Count() 
                    / 2 - 1))) / 2.0);
            }
            else {        
                return Convert.ToDouble(((data.get_Item((data.get_Count() 
                    / 2))))) ;
            }
        }
        else {
            return 0.0 ;
        }
    } //Average


    // Get the AverageInfo object from the caller's format provider,
    // or use the local default.
    protected AverageInfo GetAverageInfo(IFormatProvider provider)
    {
        AverageInfo avgInfo = null;

        if ( provider  != null  ) {
            avgInfo =((AverageInfo)(provider.GetFormat(
                    AverageInfo.class.ToType())));
        }

        if ( avgInfo == null  ) {
            return defaultProvider ;
        }
        else {        
            return avgInfo ;
        }
    } //GetAverageInfo

    // Calculate the average and limit the range.
    protected double CalcNLimitAverage(
        double min, double max, IFormatProvider provider)
    {
        // Get the format provider and calculate the average.
        AverageInfo avgInfo = GetAverageInfo(provider);
        double avg = Average(avgInfo.get_TypeOfAverage());

        // Limit the range, based on the minimum and maximum values 
        // for the type.
        return(avg > max) ? max :(avg < min) ? min : avg ;
    } //CalcNLimitAverage

    // The following elements are required by IConvertible.
    // None of these conversion functions throw exceptions. When
    // the data is out of range for the type, the appropriate
    // MinValue or MaxValue is used.
    public TypeCode GetTypeCode()
    {
        return TypeCode.Object ;
    } //GetTypeCode

    public boolean ToBoolean(IFormatProvider provider) 
    {
        // ToBoolean is false if the dataset is empty.
        if ( data.get_Count() <= 0  ) {
            return false ;
        }

        // For median averaging, ToBoolean is true if any 
        // non-discarded elements are nonzero.
        else {
            if ( AverageType.Median == GetAverageInfo(
                provider).get_TypeOfAverage()  ) {
                if ( (data.get_Count() % 2) == 0  ) {
                    return Convert.ToDouble(data.get_Item((data.get_Count() 
                        / 2))) != 0.0 || Convert.ToDouble(data.get_Item(
                        (data.get_Count() / 2 - 1))) != 0.0;
                }
                else {
                    return Convert.ToDouble(data.get_Item((data.get_Count() 
                        / 2))) != 0.0;
                }
            }

            // For arithmetic or geometric mean averaging, ToBoolean is 
            // true if any element of the dataset is nonzero.  
            else {
                for(int index=0; index < data.get_Count(); index++) {
                    if (Convert.ToDouble(data.get_Item(index)) != 0.0) {
                        return true ;
                    }
                } 
                return false ;
            }
        }
    } //ToBoolean

    public ubyte ToByte(IFormatProvider provider)
    {
        return Convert.ToByte(CalcNLimitAverage(0, 255, provider));
    } //ToByte

    public char ToChar(IFormatProvider provider) 
    {
        return Convert.ToChar(Convert.ToUInt16(CalcNLimitAverage(Char.MinValue,
            Char.MaxValue, provider))) ;
    } //ToChar

    // Convert to DateTime by adding the calculated average as 
    // seconds to the current date and time. A valid DateTime is 
    // always returned.
    public DateTime ToDateTime(IFormatProvider provider)
    {
        double seconds = Average(GetAverageInfo(provider).get_TypeOfAverage());
        try {
            return DateTime.get_Now().AddSeconds(seconds) ;
        }
        catch(ArgumentOutOfRangeException exp) {
            return(seconds < 0.0) ? DateTime.MinValue : DateTime.MaxValue ;
        }
    } //ToDateTime

    public System.Decimal ToDecimal(IFormatProvider provider)
    {
        // The Double conversion rounds Decimal.MinValue and 
        // Decimal.MaxValue to invalid Decimal values, so the 
        // following limits must be used.
        return Convert.ToDecimal(CalcNLimitAverage(-7.92281625142643E+28, 
            7.92281625142643E+28, provider)) ;
    } //ToDecimal

    public double ToDouble(IFormatProvider provider)
    {
        return Average(GetAverageInfo(provider).get_TypeOfAverage()) ;
    } //ToDouble

    public short ToInt16(IFormatProvider provider)
    {
        return Convert.ToInt16(CalcNLimitAverage(Int16.MinValue, 
            Int16.MaxValue, provider)) ;
    } //ToInt16

    public int ToInt32(IFormatProvider provider)
    {
        return Convert.ToInt32(CalcNLimitAverage(Int32.MinValue, Int32.MaxValue,
            provider)) ;
    } //ToInt32

    public long ToInt64(IFormatProvider provider) 
    {
        // The Double conversion rounds Int64.MinValue and 
        // Int64.MaxValue to invalid Int64 values, so the following 
        // limits must be used.
        return Convert.ToInt64(CalcNLimitAverage(-9223372036854775000L, 
            9223372036854775000L, provider)) ;
    } //ToInt64

    public byte ToSByte(IFormatProvider provider)
    {
        return Convert.ToSByte(CalcNLimitAverage(SByte.MinValue, SByte.MaxValue,
            provider)) ;
    } //ToSByte

    public float ToSingle(IFormatProvider provider)
    {
        return Convert.ToSingle(CalcNLimitAverage(Single.MinValue, 
            Single.MaxValue, provider)) ;
    } //ToSingle

    public UInt16 ToUInt16(IFormatProvider provider)
    {
        return Convert.ToUInt16(CalcNLimitAverage(
            Convert.ToDouble(UInt16.MinValue), 
            Convert.ToDouble(UInt16.MaxValue), provider));
    } //ToUInt16

    public UInt32 ToUInt32(IFormatProvider provider)
    {
        return Convert.ToUInt32(CalcNLimitAverage(
            Convert.ToDouble(UInt32.MinValue), 
            Convert.ToDouble(UInt32.MaxValue), provider)) ;
    } //ToUInt32

    public UInt64 ToUInt64(IFormatProvider provider)
    {
        // The Double conversion rounds UInt64.MaxValue to an invalid
        // UInt64 value, so the following limit must be used.
        return Convert.ToUInt64(CalcNLimitAverage(0, 1.84467440737095E+19, 
            provider)) ;
    } //ToUInt64

    public Object ToType(Type conversionType, IFormatProvider provider)
    {
        return Convert.ChangeType((System.Double)Average(
            GetAverageInfo(provider).get_TypeOfAverage()), conversionType) ;
    } //ToType


    public String ToString(IFormatProvider provider)
    {
        int avgType = GetAverageInfo(provider).get_TypeOfAverage();
        return String.Format("( {0}: {1} )", (Int32)avgType, 
            ((System.Double)Average(avgType)).ToString("G10"));
    } //ToString
} //DataSet

class IConvertibleProviderDemo
{
    // Display a DataSet with three different format providers.
    public static void DisplayDataSet(DataSet ds) 
        throws InvalidOperationException
    {
        String fmt = "{0,-12}{1,20}{2,20}{3,20}";
        AverageInfo median =  new AverageInfo(AverageType.Median);
        AverageInfo geMean = new AverageInfo(AverageType.GeometricMean);

        // Display the dataset elements.
        if ( ds.get_Count() > 0  ) {
            Console.Write("\nDataSet: [{0}", (System.Double)ds.get_Item( 0));
            for(int iX=1; iX < ds.get_Count(); iX++) {            
                Console.Write(", {0}",(System.Double) ds.get_Item( iX));
            } 
            Console.WriteLine("]\n");
        }

        Console.WriteLine(fmt, new Object[] { "Convert.", "Default", 
            "Geometric Mean", "Median" });
        Console.WriteLine(fmt, new Object[] { "--------", "-------", 
            "--------------", "------" });
        Console.WriteLine(fmt, new Object[] { "ToBoolean", 
            (System.Boolean)Convert.ToBoolean(ds, null),
            (System.Boolean)Convert.ToBoolean(ds, geMean),
            (System.Boolean)Convert.ToBoolean(ds, median) });
        Console.WriteLine(fmt, new Object[] { "ToByte", 
            (Convert.ToString(Convert.ToByte(ds, null))), 
            (Convert.ToString(Convert.ToByte(ds, geMean))), 
            (Convert.ToString(Convert.ToByte(ds, median))) });
        Console.WriteLine(fmt, new Object[] { "ToChar", 
            (Char)Convert.ToChar(ds, null), 
            (Char)Convert.ToChar(ds, geMean), 
            (Char)Convert.ToChar(ds, median) });
        Console.WriteLine("{0,-12}{1,20:yyyy-MM-dd HH:mm:ss}"
            + "{2,20:yyyy-MM-dd HH:mm:ss}{3,20:yyyy-MM-dd HH:mm:ss}",
            new Object[] { "ToDateTime", Convert.ToDateTime(ds, null), 
            Convert.ToDateTime(ds, geMean),    Convert.ToDateTime(ds, median) });
        Console.WriteLine(fmt, new Object[] { "ToDecimal", 
            Convert.ToDecimal(ds, null), Convert.ToDecimal(ds, geMean), 
            Convert.ToDecimal(ds, median) });
        Console.WriteLine(fmt, new Object[] { "ToDouble", 
            (System.Double)Convert.ToDouble(ds, null), 
            (System.Double)Convert.ToDouble(ds, geMean), 
            (System.Double)Convert.ToDouble(ds, median) });
        Console.WriteLine(fmt, new Object[] { "ToInt16", 
            (System.Int16)Convert.ToInt16(ds, null), 
            (System.Int16)Convert.ToInt16(ds, geMean), 
            (System.Int16)Convert.ToInt16(ds, median) });
        Console.WriteLine(fmt, new Object[] { "ToInt32", 
            (System.Int32)Convert.ToInt32(ds, null), 
            (System.Int32)Convert.ToInt32(ds, geMean), 
            (System.Int32)Convert.ToInt32(ds, median) });
        Console.WriteLine(fmt, new Object[] { "ToInt64", 
            (System.Int64)Convert.ToInt64(ds, null), 
            (System.Int64)Convert.ToInt64(ds, geMean), 
            (System.Int64)Convert.ToInt64(ds, median) });
        Console.WriteLine(fmt, new Object[] { "ToSByte", 
            (System.SByte)Convert.ToSByte(ds, null), 
            (System.SByte)Convert.ToSByte(ds, geMean), 
            (System.SByte)Convert.ToSByte(ds, median) });
        Console.WriteLine(fmt, new Object[] { "ToSingle", 
            new Decimal(Convert.ToSingle(ds, null)), 
            new Decimal(Convert.ToSingle(ds, geMean)), 
            new Decimal(Convert.ToSingle(ds, median) )});
        Console.WriteLine(fmt, new Object[] { "ToUInt16", 
            Convert.ToUInt16(ds, null), 
            Convert.ToUInt16(ds, geMean), 
            Convert.ToUInt16(ds, median)});
        Console.WriteLine(fmt, new Object[] { "ToUInt32", 
            Convert.ToUInt32(ds, null), 
            Convert.ToUInt32(ds, geMean), 
            Convert.ToUInt32(ds, median)});
        Console.WriteLine(fmt, new Object[] { "ToUInt64", 
            Convert.ToUInt64(ds, null), 
            Convert.ToUInt64(ds, geMean), 
            Convert.ToUInt64(ds, median)});
    } //DisplayDataSet

    public static void main(String[] args) throws InvalidOperationException
    {
        Console.WriteLine(("This example of " 
            + "the Convert.ToXXX( object, IFormatProvider ) methods "
            + "\ngenerates the following output. The example " 
            + "displays the values \nreturned by the methods, " 
            + "using several IFormatProvider objects.\n"));

        DataSet ds1 = new DataSet(new double[] { 10.5, 22.2, 45.9, 88.7,
                    156.05, 297.6 });
        DisplayDataSet(ds1);
        DataSet ds2 = new DataSet(new double[] { 359999.95, 425000, 499999.5, 
                    775000, 1695000 });
        DisplayDataSet(ds2);
    } //main
} //IConvertibleProviderDemo

/*
This example of the Convert.ToXXX( object, IFormatProvider ) methods
generates the following output. The example displays the values
returned by the methods, using several IFormatProvider objects.

DataSet: [10.5, 22.2, 45.9, 88.7, 156.05, 297.6]

Convert.                 Default      Geometric Mean              Median
--------                 -------      --------------              ------
ToBoolean                   True                True                True
ToByte                       103                  59                  67
ToChar                         g                   ;                   C
ToDateTime   2003-05-13 15:04:12 2003-05-13 15:03:28 2003-05-13 15:03:35
ToDecimal       103.491666666667    59.4332135445164                67.3
ToDouble        103.491666666667    59.4332135445164                67.3
ToInt16                      103                  59                  67
ToInt32                      103                  59                  67
ToInt64                      103                  59                  67
ToSByte                      103                  59                  67
ToSingle                103.4917            59.43321                67.3
ToUInt16                     103                  59                  67
ToUInt32                     103                  59                  67
ToUInt64                     103                  59                  67

DataSet: [359999.95, 425000, 499999.5, 775000, 1695000]

Convert.                 Default      Geometric Mean              Median
--------                 -------      --------------              ------
ToBoolean                   True                True                True
ToByte                       255                 255                 255
ToChar                         ?                   ?                   ?
ToDateTime   2003-05-22 07:39:08 2003-05-20 22:28:45 2003-05-19 09:55:48
ToDecimal              750999.89    631577.237188435            499999.5
ToDouble               750999.89    631577.237188435            499999.5
ToInt16                    32767               32767               32767
ToInt32                   751000              631577              500000
ToInt64                   751000              631577              500000
ToSByte                      127                 127                 127
ToSingle                750999.9            631577.3            499999.5
ToUInt16                   65535               65535               65535
ToUInt32                  751000              631577              500000
ToUInt64                  751000              631577              500000
*/

Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

XNA Framework

Supported in: 1.0

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