Exception 构造函数

定义

命名空间:

System

程序集:

System.Runtime.dll

初始化 Exception 类的新实例。

重载

Exception()	初始化 Exception 类的新实例。
Exception(String)	用指定的错误消息初始化 Exception 类的新实例。
Exception(SerializationInfo, StreamingContext)	已过时. 用序列化数据初始化 Exception 类的新实例。
Exception(String, Exception)	使用指定的错误消息和对作为此异常原因的内部异常的引用来初始化 Exception 类的新实例。

Exception()

Source:

Exception.CoreCLR.cs

初始化 Exception 类的新实例。

C#

public Exception ();

示例

下面的代码示例派生 Exception 使用预定义消息的 。 该代码演示如何对派生类和基 Exception 类使用无参数构造函数。

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)
*/

注解

此构造函数将新实例的 Message 属性初始化为系统提供的消息，该消息描述错误并考虑当前系统区域性。

所有派生类都应提供此无参数构造函数。 下表显示了 Exception 实例的初始属性值。

properties	值
InnerException	空引用（在 Visual Basic 中为 Nothing）。
Message	系统提供的本地化说明。

Exception(String)

Source:

Exception.cs

用指定的错误消息初始化 Exception 类的新实例。

C#

public Exception (string? message);

参数

message

String

描述错误的消息。

示例

下面的代码示例为特定条件派生 Exception 了 。 该代码演示了如何使用构造函数，该构造函数将调用方指定的消息作为派生类和基 Exception 类的参数。

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)
*/

注解

此构造函数使用 参数初始化 Message 新实例的 message 属性。 message如果 参数为 null，则这与调用Exception构造函数相同。

下表显示了 Exception 实例的初始属性值。

properties	值
InnerException	空引用（在 Visual Basic 中为 Nothing）。
Message	错误消息字符串。

Exception(SerializationInfo, StreamingContext)

Source:

Exception.CoreCLR.cs

注意

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

用序列化数据初始化 Exception 类的新实例。

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);

参数

info

SerializationInfo

包含有关所引发异常的序列化对象数据的 SerializationInfo。

context

StreamingContext

StreamingContext，它包含关于源或目标的上下文信息。

属性

ObsoleteAttribute

例外

ArgumentNullException

info 为 null。

SerializationException

类名为 null 或者 HResult 为零 (0)。

示例

下面的代码示例定义派生的可 Exception 序列化类。 代码强制出现除 0 错误，然后使用 (SerializationInfo) StreamingContext 构造函数创建派生异常的实例。 代码将 实例序列化为文件，将文件反序列化为引发的新异常，然后捕获并显示异常的数据。

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()
*/

注解

在反序列化期间调用此构造函数以重新构造在流上传输的异常对象。 有关详细信息，请参阅 XML 和 SOAP 序列化。

另请参阅

• SerializationInfo
• StreamingContext
• XML 和 SOAP 序列化

Exception(String, Exception)

Source:

Exception.cs

使用指定的错误消息和对作为此异常原因的内部异常的引用来初始化 Exception 类的新实例。

C#

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

参数

message

String

解释异常原因的错误消息。

innerException

Exception

导致当前异常的异常；如果未指定内部异常，则是一个 null 引用（在 Visual Basic 中为 Nothing）。

示例

下面的代码示例为特定条件派生 Exception 了 。 该代码演示了对派生类和基 Exception 类使用采用消息和内部异常作为参数的构造函数。

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()
*/

注解

因前一个异常而直接引发的异常应在 InnerException 属性中包含对前一个异常的引用。 InnerException 属性返回传递到构造函数中的相同值，或者如果 Nothing 属性不向构造函数提供内部异常值，则为空引用（在 Visual Basic 中为 InnerException）。

下表显示了 Exception 实例的初始属性值。

properties	“值”
InnerException	内部异常引用。
Message	错误消息字符串。