WebException Konstruktory

Definice

Obor názvů:

System.Net

Sestavení:

netstandard.dll, System.Net.Requests.dll

Inicializuje novou instanci WebException třídy.

Přetížení

Name	Description
WebException()	Inicializuje novou instanci WebException třídy.
WebException(String)	Inicializuje novou instanci WebException třídy se zadanou chybovou zprávou.
WebException(SerializationInfo, StreamingContext)	Zastaralé. Inicializuje novou instanci WebException třídy ze zadaných SerializationInfo a StreamingContext instancí.
WebException(String, WebExceptionStatus)	Inicializuje novou instanci WebException třídy se zadanou chybovou zprávou a stavem.
WebException(String, Exception)	Inicializuje novou instanci WebException třídy se zadanou chybovou zprávou a vnořenou výjimkou.
WebException(String, Exception, WebExceptionStatus, WebResponse)	Inicializuje novou instanci WebException třídy se zadanou chybovou zprávou, vnořenou výjimkou, stavem a odpovědí.

WebException()

Zdroj:

WebException.cs

Inicializuje novou instanci WebException třídy.

public:
 WebException();

public WebException();

Public Sub New ()

Příklady

Následující příklad vyvolá výchozí WebException.

 try   
 {
     // A 'Socket' object has been created.
     Socket httpSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

     // The IPaddress of the unknown uri is resolved using the 'Dns.Resolve' method. 
     
     IPHostEntry hostEntry = Dns.Resolve("http://www.contoso.com");

     IPAddress serverAddress = hostEntry.AddressList[0];
     IPEndPoint endPoint = new IPEndPoint(serverAddress, 80);
     httpSocket.Connect(endPoint);
     Console.WriteLine("Connection created successfully");
     httpSocket.Close();
  }
catch(SocketException e)
  {
  String exp = e.Message;	
  // Throw the WebException with no parameters.
     throw new WebException();
  }

Try
    ' A 'Socket' object has been created.
    Dim httpSocket As New Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)
    
    ' The IPaddress of the unknown uri is resolved using the 'Dns.Resolve' method. 
     ' which leads to the 'SocketException' exception. 
    
    Dim hostEntry As IPHostEntry = Dns.Resolve("http://www.contoso.com")
    
    Dim serverAddress As IPAddress = hostEntry.AddressList(0)
    Dim endPoint As New IPEndPoint(serverAddress, 80)
    httpSocket.Connect(endPoint)
    Console.WriteLine("Connection created successfully")
    httpSocket.Close()
Catch e As SocketException
    Dim exp As [String] = e.Message
    ' Throw the WebException with no parameters.
    Throw New WebException()
End Try

Poznámky

Konstruktor bez parametrů inicializuje novou instanci WebException třídy. Vlastnost Message se inicializuje na zprávu zadanou systémem, která popisuje chybu. Tato zpráva bere v úvahu aktuální systémovou jazykovou verzi. Vlastnosti InnerException jsou Response inicializovány do null. Vlastnost Status je inicializována na RequestCanceled.

WebException(String)

Zdroj:

WebException.cs

Inicializuje novou instanci WebException třídy se zadanou chybovou zprávou.

public:
 WebException(System::String ^ message);

public WebException(string? message);

new System.Net.WebException : string -> System.Net.WebException

Public Sub New (message As String)

Parametry

message

String

Text chybové zprávy.

Příklady

Následující příklad vyvolá WebException chybu zadáním chybové zprávy.

 try
{
     // A 'Socket' object has been created.
     Socket httpSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

     // The IPaddress of the unknown uri is resolved using the 'Dns.Resolve' method. 
     IPHostEntry hostEntry = Dns.Resolve(connectUri);

     IPAddress serverAddress = hostEntry.AddressList[0];
     IPEndPoint endPoint = new IPEndPoint(serverAddress, 80);
     httpSocket.Connect(endPoint);
     Console.WriteLine("Connection created successfully");
     httpSocket.Close();
  }
catch(SocketException e)
  {		     
     Console.WriteLine("\nException thrown.\nThe Original Message is: "+e.Message);
     // Throw the 'WebException' object with a message string specific to the situation.
     throw new WebException("Unable to locate the Server with 'www.contoso.com' Uri.");
  }

Try
    ' A 'Socket' object has been created.
    Dim httpSocket As New Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)
    
    ' The IPaddress of the unknown uri is resolved using the 'Dns.Resolve' method. 
     
    Dim hostEntry As IPHostEntry = Dns.Resolve(connectUri)
    
    Dim serverAddress As IPAddress = hostEntry.AddressList(0)
    Dim endPoint As New IPEndPoint(serverAddress, 80)
    httpSocket.Connect(endPoint)
    Console.WriteLine("Connection created successfully")
    httpSocket.Close()
Catch e As SocketException
    Console.WriteLine((ControlChars.Cr + "Exception thrown." + ControlChars.Cr + "The Original Message is: " + e.Message))
    ' Throw the 'WebException' object with a message string specific to the situation.
    Throw New WebException("Unable to locate the Server with 'www.contoso.com' Uri.")
End Try

Poznámky

Instance WebException se inicializuje s Message vlastností nastavenou na hodnotu message. Pokud message ano null, Message vlastnost je inicializována do zprávy zadané systémem. Vlastnosti InnerException jsou Response inicializovány do null. Vlastnost Status je inicializována na RequestCanceled.

Viz také

• Exception

WebException(SerializationInfo, StreamingContext)

Zdroj:

WebException.cs

Upozornění

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

Inicializuje novou instanci WebException třídy ze zadaných SerializationInfo a StreamingContext instancí.

protected:
 WebException(System::Runtime::Serialization::SerializationInfo ^ serializationInfo, System::Runtime::Serialization::StreamingContext streamingContext);

[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 WebException(System.Runtime.Serialization.SerializationInfo serializationInfo, System.Runtime.Serialization.StreamingContext streamingContext);

[<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}")>]
new System.Net.WebException : System.Runtime.Serialization.SerializationInfo * System.Runtime.Serialization.StreamingContext -> System.Net.WebException

Protected Sub New (serializationInfo As SerializationInfo, streamingContext As StreamingContext)

Parametry

serializationInfo

SerializationInfo

A SerializationInfo obsahující informace potřebné k serializaci nového WebException.

streamingContext

StreamingContext

A StreamingContext , který obsahuje zdroj serializovaného datového proudu, který je přidružen k nové WebException.

Atributy

ObsoleteAttribute

Poznámky

Tento konstruktor implementuje ISerializable rozhraní pro WebException třídu.

Viz také

• ISerializable

WebException(String, WebExceptionStatus)

Zdroj:

WebException.cs

Inicializuje novou instanci WebException třídy se zadanou chybovou zprávou a stavem.

public:
 WebException(System::String ^ message, System::Net::WebExceptionStatus status);

public WebException(string? message, System.Net.WebExceptionStatus status);

new System.Net.WebException : string * System.Net.WebExceptionStatus -> System.Net.WebException

Public Sub New (message As String, status As WebExceptionStatus)

Parametry

message

String

Text chybové zprávy.

status

WebExceptionStatus

Jedna z WebExceptionStatus hodnot.

Příklady

Následující příklad vyvolá WebException zadáním chybové zprávy a a WebExceptionStatus.

 try
{
       // A 'Socket' object has been created.
       Socket httpSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

      // The IPaddress of the unknown uri is resolved using the 'Dns.Resolve' method. 
  
      IPHostEntry hostEntry = Dns.Resolve("http://www.contoso.com");

      IPAddress serverAddress = hostEntry.AddressList[0];
      IPEndPoint endPoint = new IPEndPoint(serverAddress, 80);
      httpSocket.Connect(endPoint);
      Console.WriteLine("Connection created successfully");
      httpSocket.Close();
   }
catch(SocketException e)
  {
      Console.WriteLine("\nException thrown.\nThe Original Message is: "+e.Message);
      // Throw the 'WebException' object with a message string and message status specific to the situation.
      throw new WebException("Unable to locate the Server with 'www.contoso.com' Uri.",WebExceptionStatus.NameResolutionFailure);
  }

Try
    ' A 'Socket' object has been created.
    Dim httpSocket As New Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)
    
    ' The IPaddress of the unknown uri is resolved using the 'Dns.Resolve' method. 
     
    Dim hostEntry As IPHostEntry = Dns.Resolve(connectUri)
    
    Dim serverAddress As IPAddress = hostEntry.AddressList(0)
    Dim endPoint As New IPEndPoint(serverAddress, 80)
    httpSocket.Connect(endPoint)
    Console.WriteLine("Connection created successfully")
    httpSocket.Close()
Catch e As SocketException
    Console.WriteLine((ControlChars.Cr + "Exception thrown." + ControlChars.Cr + "The Original Message is: " + e.Message))
    ' Throw the 'WebException' object with a message string and message status specific to the situation.
    Throw New WebException("Unable to locate the Server with 'www.contoso.com' Uri.", WebExceptionStatus.NameResolutionFailure)
End Try

Poznámky

Instance WebException je inicializována s Message vlastností nastavenou na hodnotu message a Status vlastnost nastavena na hodnotu .status Pokud message ano null, Message vlastnost je inicializována do zprávy zadané systémem. Vlastnosti InnerException jsou Response inicializovány do null.

WebException(String, Exception)

Zdroj:

WebException.cs

Inicializuje novou instanci WebException třídy se zadanou chybovou zprávou a vnořenou výjimkou.

public:
 WebException(System::String ^ message, Exception ^ innerException);

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

new System.Net.WebException : string * Exception -> System.Net.WebException

Public Sub New (message As String, innerException As Exception)

Parametry

message

String

Text chybové zprávy.

innerException

Exception

Vnořená výjimka.

Příklady

Následující příklad vyvolá WebException výjimku zadáním chybové zprávy a vnořené výjimky.

   try
   {
          // A 'Socket' object has been created.
          Socket httpSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

          // The IPaddress of the unknown uri is resolved using the 'Dns.Resolve' method. 
       
          IPHostEntry hostEntry = Dns.Resolve(connectUri);

          IPAddress serverAddress = hostEntry.AddressList[0];
          IPEndPoint endPoint = new IPEndPoint(serverAddress, 80);
          httpSocket.Connect(endPoint);
          Console.WriteLine("Connection created successfully");
          httpSocket.Close();		 
    }
  catch(SocketException e)
{ 
       Console.WriteLine("\nException thrown.\nThe Original Message is: "+e.Message);
       //  Throw the 'WebException' object with a message string specific to the situation; 
          //  and the 'InnerException' which actually lead to this exception.
          throw new WebException("Unable to locate the Server with 'www.contoso.com' Uri.",e);
    }

Try
    ' A 'Socket' object has been created.
    Dim httpSocket As New Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)
    
    ' The IPaddress of the unknown uri is resolved using the 'Dns.Resolve' method. 
     Dim hostEntry As IPHostEntry = Dns.Resolve(connectUri)
    
    Dim serverAddress As IPAddress = hostEntry.AddressList(0)
    Dim endPoint As New IPEndPoint(serverAddress, 80)
    httpSocket.Connect(endPoint)
    Console.WriteLine("Connection created successfully")
    httpSocket.Close()
Catch e As SocketException
    Console.WriteLine((ControlChars.Cr + "Exception thrown." + ControlChars.Cr + "The Original Message is: " + e.Message))
    ' Throw the 'WebException' object with a message string specific to the situation. 
     ' and the 'InnerException' which actually lead to this exception.
    Throw New WebException("Unable to locate the Server with 'www.contoso.com' Uri.", e)
End Try

Poznámky

Instance WebException je inicializována s Message vlastností nastavenou na hodnotu message a InnerException vlastnost nastavena na hodnotu .innerException Pokud message ano null, Message vlastnost je inicializována do zprávy zadané systémem. Vlastnosti InnerException jsou Response inicializovány do null. Vlastnost Status je inicializována na RequestCanceled.

Viz také

• Exception

WebException(String, Exception, WebExceptionStatus, WebResponse)

Zdroj:

WebException.cs

Inicializuje novou instanci WebException třídy se zadanou chybovou zprávou, vnořenou výjimkou, stavem a odpovědí.

public:
 WebException(System::String ^ message, Exception ^ innerException, System::Net::WebExceptionStatus status, System::Net::WebResponse ^ response);

public WebException(string? message, Exception? innerException, System.Net.WebExceptionStatus status, System.Net.WebResponse? response);

new System.Net.WebException : string * Exception * System.Net.WebExceptionStatus * System.Net.WebResponse -> System.Net.WebException

Public Sub New (message As String, innerException As Exception, status As WebExceptionStatus, response As WebResponse)

Parametry

message

String

Text chybové zprávy.

innerException

Exception

Vnořená výjimka.

status

WebExceptionStatus

Jedna z WebExceptionStatus hodnot.

response

WebResponse

Instance WebResponse , která obsahuje odpověď vzdáleného hostitele.

Příklady

Následující příklad vyvolá WebException zadáním chybové zprávy a a WebExceptionStatus.

      // Send the data. 
      Encoding ASCII = Encoding.ASCII;
      string requestPage = "GET /nhjj.htm HTTP/1.1\r\nHost: " + connectUri + "\r\nConnection: Close\r\n\r\n";
      Byte[] byteGet = ASCII.GetBytes(requestPage);
      Byte[] recvBytes = new Byte[256];

      // Create an 'IPEndPoint' object.
 
      IPHostEntry hostEntry = Dns.Resolve(connectUri);
      IPAddress serverAddress = hostEntry.AddressList[0];
      IPEndPoint endPoint = new IPEndPoint(serverAddress, 80);

      // Create a 'Socket' object  for sending data.
      Socket connectSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream,ProtocolType.Tcp);
 
      // Connect to host using 'IPEndPoint' object.

      connectSocket.Connect(endPoint);
 
      // Sent the 'requestPage' text to the host.
      connectSocket.Send(byteGet, byteGet.Length, 0);
 
      // Receive the information sent by the server.
      Int32 bytesReceived = connectSocket.Receive(recvBytes, recvBytes.Length, 0);
      String headerString = ASCII.GetString(recvBytes, 0, bytesReceived);

     // Check whether 'status 404' is there or not in the information sent by server.
     if(headerString.IndexOf("404")!=-1)
     {	 
         bytesReceived = connectSocket.Receive(recvBytes, recvBytes.Length, 0);
         MemoryStream memoryStream = new MemoryStream(recvBytes);
         getStream = (Stream) memoryStream;
 
         // Create a 'WebResponse' object
         WebResponse myWebResponse = (WebResponse) new HttpConnect(getStream);
         Exception myException = new Exception("File Not found");

         // Throw the 'WebException' object with a message string, message status,InnerException and WebResponse
         throw new WebException("The Requested page is not found.",myException,WebExceptionStatus.ProtocolError,myWebResponse);
     }

     connectSocket.Close();

     ' Send the data. 
       Dim ASCII As Encoding = Encoding.ASCII
       Dim requestPage As String = "GET /nhjj.htm HTTP/1.1" + ControlChars.Lf + ControlChars.Cr + "Host: " + connectUri + ControlChars.Lf + ControlChars.Cr + "Connection: Close" + ControlChars.Lf + ControlChars.Cr + ControlChars.Lf + ControlChars.Cr
       Dim byteGet As [Byte]() = ASCII.GetBytes(requestPage)
       Dim recvBytes(256) As [Byte]
       
       ' Create an 'IPEndPoint' object.
       Dim hostEntry As IPHostEntry = Dns.Resolve(connectUri)
       Dim serverAddress As IPAddress = hostEntry.AddressList(0)
       Dim endPoint As New IPEndPoint(serverAddress, 80)
       
       ' Create a 'Socket' object  for sending data.
       Dim connectSocket As New Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)
       
       ' Connect to host using 'IPEndPoint' object.
       connectSocket.Connect(endPoint)
       
       ' Sent the 'requestPage' text to the host.
       connectSocket.Send(byteGet, byteGet.Length, 0)
       
       ' Receive the information sent by the server.
       Dim bytesReceived As Int32 = connectSocket.Receive(recvBytes, recvBytes.Length, 0)
       Dim headerString As [String] = ASCII.GetString(recvBytes, 0, bytesReceived)
      
       ' Check whether 'status 404' is there or not in the information sent by server.
       If headerString.IndexOf("404") <> False Then
           bytesReceived = connectSocket.Receive(recvBytes, recvBytes.Length, 0)
           Dim memoryStream As New MemoryStream(recvBytes)
           getStream = CType(memoryStream, Stream)
           
           ' Create a 'WebResponse' object.
           Dim myWebResponse As WebResponse = CType(New HttpConnect(getStream), WebResponse)
           Dim myException As New Exception("File Not found")
           
           ' Throw the 'WebException' object with a message string, message status,InnerException and WebResponse.
           Throw New WebException("The Requested page is not found.", myException, WebExceptionStatus.ProtocolError, myWebResponse)
       End If 

       connectSocket.Close()

Poznámky

Instance WebException je inicializována vlastností Message nastavena na hodnotu message, InnerException vlastnost nastavena na hodnotu innerException, Status vlastnost nastavena na hodnotu , statusa Response vlastnost nastavena na hodnotu response. Pokud message ano null, Message vlastnost je inicializována do zprávy zadané systémem.