Exception 建構函式

定義

命名空間:

System

組件:

System.Runtime.dll

初始化 Exception 類別的新執行個體。

多載

Exception()	初始化 Exception 類別的新執行個體。
Exception(String)	使用指定的錯誤訊息，初始化 Exception 類別的新執行個體。
Exception(SerializationInfo, StreamingContext)	已淘汰. 使用序列化資料，初始化 Exception 類別的新執行個體。
Exception(String, Exception)	使用指定的錯誤訊息以及造成此例外狀況的內部例外狀況的參考，初始化 Exception 類別的新執行個體。

Exception()

來源:

Exception.CoreCLR.cs

初始化 Exception 類別的新執行個體。

C#

public Exception ();

範例

下列程式碼範例會 Exception 衍生使用預先定義訊息的 。 此程式碼示範針對衍生類別和基 Exception 類使用無參數建構函式。

C#

// Example for the Exception( ) constructor.
using System;

namespace NDP_UE_CS
{
    // Derive an exception with a predefined message.
    class NotEvenException : Exception
    {
        public NotEvenException( ) :
            base( "The argument to a function requiring " +
                "even input is not divisible by 2." )
        { }
    }

    class NewExceptionDemo
    {
        public static void Main()
        {
            Console.WriteLine(
                "This example of the Exception( ) constructor " +
                "generates the following output." );
            Console.WriteLine(
                "\nHere, an exception is thrown using the \n" +
                "parameterless constructor of the base class.\n" );

            CalcHalf( 12 );
            CalcHalf( 15 );

            Console.WriteLine(
                "\nHere, an exception is thrown using the \n" +
                "parameterless constructor of a derived class.\n" );

            CalcHalf2( 24 );
            CalcHalf2( 27 );
        }
        
        // Half throws a base exception if the input is not even.
        static int Half( int input )
        {
            if( input % 2 != 0 )
                throw new Exception( );

            else return input / 2;
        }

        // Half2 throws a derived exception if the input is not even.
        static int Half2( int input )
        {
            if( input % 2 != 0 )
                throw new NotEvenException( );

            else return input / 2;
        }

        // CalcHalf calls Half and catches any thrown exceptions.
        static void CalcHalf(int input )
        {
            try
            {
                int halfInput = Half( input );
                Console.WriteLine(
                    "Half of {0} is {1}.", input, halfInput );
            }
            catch( Exception ex )
            {
                Console.WriteLine( ex.ToString( ) );
            }
        }

        // CalcHalf2 calls Half2 and catches any thrown exceptions.
        static void CalcHalf2(int input )
        {
            try
            {
                int halfInput = Half2( input );
                Console.WriteLine(
                    "Half of {0} is {1}.", input, halfInput );
            }
            catch( Exception ex )
            {
                Console.WriteLine( ex.ToString( ) );
            }
        }
    }
}

/*
This example of the Exception( ) constructor generates the following output.

Here, an exception is thrown using the
parameterless constructor of the base class.

Half of 12 is 6.
System.Exception: Exception of type System.Exception was thrown.
   at NDP_UE_CS.NewExceptionDemo.Half(Int32 input)
   at NDP_UE_CS.NewExceptionDemo.CalcHalf(Int32 input)

Here, an exception is thrown using the
parameterless constructor of a derived class.

Half of 24 is 12.
NDP_UE_CS.NotEvenException: The argument to a function requiring even input is
not divisible by 2.
   at NDP_UE_CS.NewExceptionDemo.Half2(Int32 input)
   at NDP_UE_CS.NewExceptionDemo.CalcHalf2(Int32 input)
*/

備註

這個建構函式會將新執行個體的 Message 屬性初始化為系統提供的訊息，該訊息會描述錯誤並考量目前系統的文化特性。

所有衍生類別都應該提供這個無參數建構函式。 下表顯示 Exception 執行個體的初始屬性值。

屬性	值
InnerException	null 參考 (在 Visual Basic 中為 Nothing)。
Message	系統提供的當地語系化描述。

Exception(String)

來源:

Exception.cs

使用指定的錯誤訊息，初始化 Exception 類別的新執行個體。

C#

public Exception (string? message);

參數

message

String

描述錯誤的訊息。

範例

下列程式碼範例會 Exception 針對特定條件衍生 的 。 程式碼示範如何針對衍生類別和基 Exception 類使用呼叫端指定的訊息做為參數的建構函式。

C#

// Example for the Exception( string ) constructor.
using System;

namespace NDP_UE_CS2
{
    // Derive an exception with a specifiable message.
    class NotEvenException : Exception
    {
        const string notEvenMessage =
            "The argument to a function requiring " +
            "even input is not divisible by 2.";

        public NotEvenException( ) :
            base( notEvenMessage )
        { }

        public NotEvenException( string auxMessage ) :
            base( String.Format( "{0} - {1}",
                auxMessage, notEvenMessage ) )
        { }
    }

    class NewSExceptionDemo
    {
        public static void Main()
        {
            Console.WriteLine(
                "This example of the Exception( string )\n" +
                "constructor generates the following output." );
            Console.WriteLine(
                "\nHere, an exception is thrown using the \n" +
                "constructor of the base class.\n" );

            CalcHalf( 18 );
            CalcHalf( 21 );

            Console.WriteLine(
                "\nHere, an exception is thrown using the \n" +
                "constructor of a derived class.\n" );

            CalcHalf2( 30 );
            CalcHalf2( 33 );
        }
        
        // Half throws a base exception if the input is not even.
        static int Half( int input )
        {
            if( input % 2 != 0 )
                throw new Exception( String.Format(
                    "The argument {0} is not divisible by 2.",
                    input ) );

            else return input / 2;
        }

        // Half2 throws a derived exception if the input is not even.
        static int Half2( int input )
        {
            if( input % 2 != 0 )
                throw new NotEvenException(
                    String.Format( "Invalid argument: {0}", input ) );

            else return input / 2;
        }

        // CalcHalf calls Half and catches any thrown exceptions.
        static void CalcHalf(int input )
        {
            try
            {
                int halfInput = Half( input );
                Console.WriteLine(
                    "Half of {0} is {1}.", input, halfInput );
            }
            catch( Exception ex )
            {
                Console.WriteLine( ex.ToString( ) );
            }
        }

        // CalcHalf2 calls Half2 and catches any thrown exceptions.
        static void CalcHalf2(int input )
        {
            try
            {
                int halfInput = Half2( input );
                Console.WriteLine(
                    "Half of {0} is {1}.", input, halfInput );
            }
            catch( Exception ex )
            {
                Console.WriteLine( ex.ToString( ) );
            }
        }
    }
}

/*
This example of the Exception( string )
constructor generates the following output.

Here, an exception is thrown using the
constructor of the base class.

Half of 18 is 9.
System.Exception: The argument 21 is not divisible by 2.
   at NDP_UE_CS.NewSExceptionDemo.Half(Int32 input)
   at NDP_UE_CS.NewSExceptionDemo.CalcHalf(Int32 input)

Here, an exception is thrown using the
constructor of a derived class.

Half of 30 is 15.
NDP_UE_CS.NotEvenException: Invalid argument: 33 - The argument to a function r
equiring even input is not divisible by 2.
   at NDP_UE_CS.NewSExceptionDemo.Half2(Int32 input)
   at NDP_UE_CS.NewSExceptionDemo.CalcHalf2(Int32 input)
*/

備註

這個建構函式會使用 message 參數，初始化 Message 新實例的 屬性。 message如果 參數為 null ，則這與呼叫建 Exception 構函式相同。

下表顯示 Exception 執行個體的初始屬性值。

屬性	值
InnerException	null 參考 (在 Visual Basic 中為 Nothing)。
Message	錯誤訊息字串。

Exception(SerializationInfo, StreamingContext)

來源:

Exception.CoreCLR.cs

警告

This API supports obsolete formatter-based serialization. It should not be called or extended by application code.

使用序列化資料，初始化 Exception 類別的新執行個體。

C#

[System.Obsolete("This API supports obsolete formatter-based serialization. It should not be called or extended by application code.", DiagnosticId="SYSLIB0051", UrlFormat="https://aka.ms/dotnet-warnings/{0}")]
protected Exception (System.Runtime.Serialization.SerializationInfo info, System.Runtime.Serialization.StreamingContext context);

參數

info

SerializationInfo

SerializationInfo，包含所擲回之例外狀況的相關序列化物件資料。

context

StreamingContext

包含有關來源或目的端內容資訊的 StreamingContext。

屬性

ObsoleteAttribute

例外狀況

ArgumentNullException

info 為 null。

SerializationException

類別名稱為 null 或 HResult 為零 (0)。

範例

下列程式碼範例會定義衍生的可 Exception 序列化類別。 程式碼會強制除以 0 錯誤，然後使用 () SerializationInfoStreamingContext 建構函式建立衍生例外狀況的實例。 程式碼會將 實例序列化為檔案、將檔案還原序列化為新的例外狀況，它會擲回該例外狀況，然後攔截並顯示例外狀況的資料。

C#

using System;
using System.IO;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Formatters.Soap;

// Define a serializable derived exception class.
[Serializable]
class SecondLevelException : Exception, ISerializable
{
    // This public constructor is used by class instantiators.
    public SecondLevelException(string message, Exception inner) :
        base(message, inner)
    {
        HelpLink = "http://MSDN.Microsoft.com";
        Source = "Exception_Class_Samples";
    }

    // This protected constructor is used for deserialization.
    protected SecondLevelException(SerializationInfo info,
        StreamingContext context) :
            base(info, context)
    { }

    // GetObjectData performs a custom serialization.
    public override void GetObjectData(SerializationInfo info,
        StreamingContext context)
    {
        // Change the case of two properties, and then use the
        // method of the base class.
        HelpLink = HelpLink.ToLower();
        Source = Source.ToUpperInvariant();

        base.GetObjectData(info, context);
    }
}

class SerializationDemo
{
    public static void Main()
    {
        Console.WriteLine(
            "This example of the Exception constructor " +
            "and Exception.GetObjectData\nwith Serialization" +
            "Info and StreamingContext parameters " +
            "generates \nthe following output.\n");

        try
        {
            // This code forces a division by 0 and catches the
            // resulting exception.
            try
            {
                int zero = 0;
                int ecks = 1 / zero;
            }
            catch (Exception ex)
            {
                // Create a new exception to throw again.
                SecondLevelException newExcept =
                    new SecondLevelException(
                        "Forced a division by 0 and threw " +
                        "another exception.", ex);

                Console.WriteLine(
                    "Forced a division by 0, caught the " +
                    "resulting exception, \n" +
                    "and created a derived exception:\n");
                Console.WriteLine("HelpLink: {0}",
                    newExcept.HelpLink);
                Console.WriteLine("Source:   {0}",
                    newExcept.Source);

                // This FileStream is used for the serialization.
                FileStream stream =
                    new FileStream("NewException.dat",
                        FileMode.Create);

                try
                {
                    // Serialize the derived exception.
                    SoapFormatter formatter =
                        new SoapFormatter(null,
                            new StreamingContext(
                                StreamingContextStates.File));
                    formatter.Serialize(stream, newExcept);

                    // Rewind the stream and deserialize the
                    // exception.
                    stream.Position = 0;
                    SecondLevelException deserExcept =
                        (SecondLevelException)
                            formatter.Deserialize(stream);

                    Console.WriteLine(
                        "\nSerialized the exception, and then " +
                        "deserialized the resulting stream " +
                        "into a \nnew exception. " +
                        "The deserialization changed the case " +
                        "of certain properties:\n");

                    // Throw the deserialized exception again.
                    throw deserExcept;
                }
                catch (SerializationException se)
                {
                    Console.WriteLine("Failed to serialize: {0}",
                        se.ToString());
                }
                finally
                {
                    stream.Close();
                }
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine("HelpLink: {0}", ex.HelpLink);
            Console.WriteLine("Source:   {0}", ex.Source);

            Console.WriteLine();
            Console.WriteLine(ex.ToString());
        }
    }
}
/*
This example displays the following output.

Forced a division by 0, caught the resulting exception,
and created a derived exception:

HelpLink: http://MSDN.Microsoft.com
Source:   Exception_Class_Samples

Serialized the exception, and then deserialized the resulting stream into a
new exception. The deserialization changed the case of certain properties:

HelpLink: http://msdn.microsoft.com
Source:   EXCEPTION_CLASS_SAMPLES

NDP_UE_CS.SecondLevelException: Forced a division by 0 and threw another except
ion. ---> System.DivideByZeroException: Attempted to divide by zero.
   at NDP_UE_CS.SerializationDemo.Main()
   --- End of inner exception stack trace ---
   at NDP_UE_CS.SerializationDemo.Main()
*/

備註

這個建構函式是在還原序列化期間呼叫，以便重新組成透過資料流傳輸的例外狀況物件。 如需詳細資訊，請參閱 < XML 和 SOAP 序列化。

另請參閱

• SerializationInfo
• StreamingContext
• XML 和 SOAP 序列化

Exception(String, Exception)

來源:

Exception.cs

使用指定的錯誤訊息以及造成此例外狀況的內部例外狀況的參考，初始化 Exception 類別的新執行個體。

C#

public Exception (string? message, Exception? innerException);

參數

message

String

解釋例外狀況原因的錯誤訊息。

innerException

Exception

造成目前例外狀況的例外狀況，若未指定內部例外狀況，則為 null 參考 (Visual Basic 中為 Nothing)。

範例

下列程式碼範例會 Exception 針對特定條件衍生 的 。 此程式碼示範如何針對衍生類別和基 Exception 類，使用接受訊息和內部例外狀況做為參數的建構函式。

C#

// Example for the Exception( string, Exception ) constructor.
using System;

namespace NDP_UE_CS
{
    // Derive an exception with a specifiable message and inner exception.
    class LogTableOverflowException : Exception
    {
        const string overflowMessage =
            "The log table has overflowed.";

        public LogTableOverflowException( ) :
            base( overflowMessage )
        { }

        public LogTableOverflowException( string auxMessage ) :
            base( String.Format( "{0} - {1}",
                overflowMessage, auxMessage ) )
        { }

        public LogTableOverflowException(
            string auxMessage, Exception inner ) :
                base( String.Format( "{0} - {1}",
                    overflowMessage, auxMessage ), inner )
        { }
    }

    class LogTable
    {
        public LogTable( int numElements )
        {
            logArea = new string[ numElements ];
            elemInUse = 0;
        }

        protected string[ ] logArea;
        protected int       elemInUse;

        // The AddRecord method throws a derived exception
        // if the array bounds exception is caught.
        public    int       AddRecord( string newRecord )
        {
            try
            {
                logArea[ elemInUse ] = newRecord;
                return elemInUse++;
            }
            catch( Exception ex )
            {
                throw new LogTableOverflowException(
                    String.Format( "Record \"{0}\" was not logged.",
                        newRecord ), ex );
            }
        }
    }

    class OverflowDemo
    {
        // Create a log table and force an overflow.
        public static void Main()
        {
            LogTable log = new LogTable( 4 );

            Console.WriteLine(
                "This example of the Exception( string, Exception )" +
                "\nconstructor generates the following output." );
            Console.WriteLine(
                "\nExample of a derived exception " +
                "that references an inner exception:\n" );
            try
            {
                for( int count = 1; ; count++ )
                {
                    log.AddRecord(
                        String.Format(
                            "Log record number {0}", count ) );
                }
            }
            catch( Exception ex )
            {
                Console.WriteLine( ex.ToString( ) );
            }
        }
    }
}

/*
This example of the Exception( string, Exception )
constructor generates the following output.

Example of a derived exception that references an inner exception:

NDP_UE_CS.LogTableOverflowException: The log table has overflowed. - Record "Lo
g record number 5" was not logged. ---> System.IndexOutOfRangeException: Index
was outside the bounds of the array.
   at NDP_UE_CS.LogTable.AddRecord(String newRecord)
   --- End of inner exception stack trace ---
   at NDP_UE_CS.LogTable.AddRecord(String newRecord)
   at NDP_UE_CS.OverflowDemo.Main()
*/

備註

被擲回以做為前一個例外狀況直接結果的例外狀況，應該在 InnerException 屬性中包含對前一個例外狀況的參考。 InnerException 屬性會傳回與傳入建構函式中相同的值；如果 Nothing 屬性不提供內部例外值給建構函式，則傳回 null 參考 (在 Visual Basic 中為 InnerException)。

下表顯示 Exception 執行個體的初始屬性值。

屬性	值
InnerException	內部例外狀況參考。
Message	錯誤訊息字串。