铸造字符串转换成的Guid在VB.Net [英] Cast a string into Guid in VB.Net

问题描述

我的GUID用户名，它需要填充会议（用户名），这是一个字符串，但格式的完美转换为GUID。

I have the Guid "UserID" , it needs to be filled with Session("UserID") which is a String , but formatted to convert perfectly to a Guid.

如果我试试这个，无法将类型为字符串类型GUID

If I try this , "Cannot Convert type string into type Guid"

       Dim UserID As New Guid()
       If HttpContext.Current.Session("UserID") IsNot Nothing Then
          UserID = HttpContext.Current.Session("UserID")
       End If

如果我尝试这个无法施展字符串类型为类型GUID

If I try this "Cannot Cast type string into type Guid"

       Dim UserID As New Guid()
       If HttpContext.Current.Session("UserID") IsNot Nothing Then
          UserID = DirectCast(HttpContext.Current.Session("UserID"), Guid)
       End If

这将字符串转换成的Guid完美，但它是不可访问的。如果声明之外

This converts the string into Guid perfectly , but it is not accessable outside of the If Statement

       If HttpContext.Current.Session("UserID") IsNot Nothing Then
         Dim UserID As new Guid(HttpContext.Current.Session("UserID"))
       End If

我无法弄清楚如何定义if语句的用户ID外，然后将其指定有条件

I can not figure out how to define UserID outside of the If statement , then assign it conditionally

推荐答案

这个尝试

Dim UserID As New Guid()
If HttpContext.Current.Session("UserID") IsNot Nothing Then
    UserID = Guid.Parse(HttpContext.Current.Session("UserID").ToString())
End If

万一你困惑，考虑到，除非我的记忆中失败，构造器的Guid将产生一个空的GUID。如果你想生成一个新的GUID使用<一个href=\"http://msdn.microsoft.com/en-us/library/system.guid.newguid\"><$c$c>Guid.NewGuid()

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