HttpWebRequest.ContentLength 属性

定义

命名空间:

System.Net

程序集:

System.Net.Requests.dll

Source:

HttpWebRequest.cs

获取或设置 Content-length HTTP 标头。

public:
 virtual property long ContentLength { long get(); void set(long value); };

public override long ContentLength { get; set; }

member this.ContentLength : int64 with get, set

Public Overrides Property ContentLength As Long

属性值

Int64

要发送到 Internet 资源的数据字节数。 默认值为 -1，指示尚未设置属性，并且没有要发送的请求数据。

例外

InvalidOperationException

请求是通过调用 GetRequestStream()、BeginGetRequestStream(AsyncCallback, Object)、GetResponse()或 BeginGetResponse(AsyncCallback, Object) 方法启动的。

ArgumentOutOfRangeException

新的 ContentLength 值小于 0。

示例

下面的代码示例将 ContentLength 属性设置为要发布的字符串的长度。

// Set the 'Method' property of the 'Webrequest' to 'POST'.
myHttpWebRequest->Method = "POST";
Console::WriteLine( "\nPlease enter the data to be posted to the (http://www.contoso.com/codesnippets/next.asp) Uri :" );

// Create a new String* Object* to POST data to the Url.
String^ inputData = Console::ReadLine();

String^ postData = String::Concat( "firstone= ", inputData );
ASCIIEncoding^ encoding = gcnew ASCIIEncoding;
array<Byte>^ byte1 = encoding->GetBytes( postData );

// Set the content type of the data being posted.
myHttpWebRequest->ContentType = "application/x-www-form-urlencoded";

// Set the content length of the String* being posted.
myHttpWebRequest->ContentLength = byte1->Length;

Stream^ newStream = myHttpWebRequest->GetRequestStream();

newStream->Write( byte1, 0, byte1->Length );
Console::WriteLine( "The value of 'ContentLength' property after sending the data is {0}", myHttpWebRequest->ContentLength );

// Close the Stream Object*.
newStream->Close();

// Set the 'Method' property of the 'Webrequest' to 'POST'.
myHttpWebRequest.Method = "POST";
Console.WriteLine ("\nPlease enter the data to be posted to the (http://www.contoso.com/codesnippets/next.asp) Uri :");

// Create a new string object to POST data to the Url.
string inputData = Console.ReadLine ();


string postData = "firstone=" + inputData;
ASCIIEncoding encoding = new ASCIIEncoding ();
byte[] byte1 = encoding.GetBytes (postData);

// Set the content type of the data being posted.
myHttpWebRequest.ContentType = "application/x-www-form-urlencoded";

// Set the content length of the string being posted.
myHttpWebRequest.ContentLength = byte1.Length;

Stream newStream = myHttpWebRequest.GetRequestStream ();

newStream.Write (byte1, 0, byte1.Length);
Console.WriteLine ("The value of 'ContentLength' property after sending the data is {0}", myHttpWebRequest.ContentLength);

// Close the Stream object.
newStream.Close ();

' Set the 'Method' property of the 'Webrequest' to 'POST'.
myHttpWebRequest.Method = "POST"

Console.WriteLine(ControlChars.Cr + "Please enter the data to be posted to the (http://www.contoso.com/codesnippets/next.asp) Uri :")
' Create a new string object to POST data to the Url.
Dim inputData As String = Console.ReadLine()
Dim postData As String = "firstone" + ChrW(61) + inputData
Dim encoding As New ASCIIEncoding()
Dim byte1 As Byte() = encoding.GetBytes(postData)
' Set the content type of the data being posted.
myHttpWebRequest.ContentType = "application/x-www-form-urlencoded"
' Set the content length of the string being posted.
myHttpWebRequest.ContentLength = byte1.Length
Dim newStream As Stream = myHttpWebRequest.GetRequestStream()
newStream.Write(byte1, 0, byte1.Length)
Console.WriteLine("The value of 'ContentLength' property after sending the data is {0}", myHttpWebRequest.ContentLength)
newStream.Close()

注解

谨慎

WebRequest、HttpWebRequest、ServicePoint和 WebClient 已过时，不应将其用于新开发。 请改用 HttpClient。

ContentLength 属性包含作为请求的 Content-length HTTP 标头发送的值。

ContentLength 属性中除 -1 以外的任何值都表示请求上传数据，并且仅允许在 Method 属性中设置上传数据的方法。

将 ContentLength 属性设置为值后，必须通过调用 GetRequestStream 方法或同时调用 BeginGetRequestStream 和 EndGetRequestStream 方法返回的请求流写入该字节数。

注意

此属性的值存储在 WebHeaderCollection中。 如果设置了 WebHeaderCollection，则属性值将丢失。