VB.NET 查询字符串有参数

Question

How do I check if a query string has a parameter in VB.NET? I'm having a hard time adapting C# code to VB.

I'm particularly interested in determining if a value-less/key-less parameter exists.

Pseudo-Code:

If Request.QueryString.Contains("test") Then
    ' ...
End If

Examples:

http://example.com/mypage.aspx?test
http://example.com/mypage.aspx?test=1
http://example.com/mypage.aspx?someparam=1&test&anotherparam=2

To clarify, I don't care whether or not test has a value. I just want to know if it is in the query string or not.

Answer 1

You were close. Use:

If Request.QueryString.ToString.Contains("test") Then
    ' ...
End If

Answer 2

if Request.QueryString("test").Count > 0  then
    ...
end if

Source: https://www.w3schools.com/asp/coll_querystring.asp

Answer 3

This should address both scenarios:

<%@ Page Language="VB"%>
<%
if Request.QueryString("test")<>"" then
  Response.Write ("EXISTS")
else 
  Response.Write ("not defined")
end if
%>