IfModifiedSince Property

[This documentation is for preview only, and is subject to change in later releases. Blank topics are included as placeholders.]

Gets or sets the value of the If-Modified-Since HTTP header.

Namespace:  System.Net
Assembly:  System.Http (in System.Http.dll)

public DateTime IfModifiedSince { get; }

Property Value

Type: System..::..DateTime
A DateTime that contains the contents of the If-Modified-Since HTTP header. The default value is the current date and time.

The IfModifiedSince property is a standard System..::..DateTime object and can contain a System..::..DateTimeKind field of DateTimeKind..::..Local, DateTimeKind..::..Utc, or DateTimeKind.Unspecified. Any kind of time can be set when using the IfModifiedSince property. If DateTimeKind.Unspecified is set or retrieved, the IfModifiedSince property is assumed to be DateTimeKind..::..Local (local time).

The classes in the System.Net namespace always write it out the IfModifiedSince property on the wire during transmission in standard form using GMT (Utc) format.

If the IfModifiedSince property is set to DateTime..::..MinValue, then the If-Modified-Since HTTP header is removed from the Headers property and the WebHeaderCollection.

If the IfModifiedSince property is DateTime..::..MinValue, this indicates that the If-Modified-Since HTTP header is not included in the Headers property and the WebHeaderCollection.

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