vb.net将此字符串转换为DateTime

Question

如何将其转换为日期时间？

Dim datestring As String = "Thu, 01 Jan 1970 00:00:00 GMT" 

我需要在HttpWebRequest的发送，例如

Dim requestAs HttpWebRequest = DirectCast(WebRequest.Create(Link), WebRequest) 
request.Method = "Post" 
request.IfModifiedSince = datestring 

，但我不能因为IfModifiedSince是Date类型，我需要精确地发送

Answer 1

你可以用System.Date做.Parse方法：

Dim datestring As String = "Thu, 01 Jan 1970 00:00:00 GMT" 
Dim requestAs HttpWebRequest = DirectCast(WebRequest.Create(Link), WebRequest) 
request.Method = "Post" 
' request.IfModifiedSince = datestring 
request.IfModifiedSince = Date.Parse(datestring) 

Answer 2

您可以使用Date.ParseExact或Date.TryParseExact：

Dim dt As Date 
If Date.TryParseExact(datestring, "ddd, dd MMM yyyy hh:mm:ss 'GMT'", CultureInfo.InvariantCulture, DateTimeStyles.None, dt) Then 
    Console.WriteLine(dt.ToShortDateString()) 
End If 

编辑：它似乎还与Date.Parse(datestring)