This function will give you 100% control over the QueryString -- perfect for programmers who use QueryString manipulation a lot.
I wrote this function when I kept having to change values of the QueryString and remove some, add some, etc., etc..
It takes four (4) parameters:
oldUrl = the current QueryString you would like manipulated
qsName = the name of the QueryField you would like to modify/remove/add
newValue = the new value you would like for the QueryField. set to "" if removing
del = an optional integer bit flag; if set to 1 it will remove the QueryField/QueryFieldValue from the QueryString.
Here is the code, enjoy! (I am always welcome to new suggestions)
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Function ChangeValue(ByVal oldUrl As String, ByVal qsName As String, ByVal newValue As String, Optional ByVal del As Integer = 0) As String
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Dim newUrl As String = ""
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' Check if the [qsName] is currently in the [oldUrl]
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If InStr(oldUrl, qsName & "=")
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oldUrl += "&"
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Dim pos1 As Integer, pos2 As Integer
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If del = 1
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pos1 = oldUrl.IndexOf(qsName & "=")
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pos2 = oldUrl.IndexOf("&", pos1) + 1
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Else
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pos1 = oldUrl.IndexOf(qsName & "=") + qsName.Length + 1
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pos2 = oldUrl.IndexOf("&", pos1)
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End If
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Dim chunk_1 As String = oldUrl.SubString(0, pos1)
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Dim chunk_2 As String = oldUrl.SubString(pos2)
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If del = 1
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newUrl = chunk_1 & chunk_2
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Else
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newUrl = chunk_1 & newValue & chunk_2
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End If
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newUrl = newUrl.SubString(0, (newUrl.Length - 1))
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Else
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If del = 1
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Return oldUrl
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End If
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' Append the new value to the [oldUrl] and make it a [newUrl]
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If oldUrl.EndsWith("?")
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newUrl = oldUrl & qsName & "=" & newValue
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ElseIf InStr(oldUrl, "?") AndAlso oldUrl.EndsWith("?") = False
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If oldUrl.EndsWith("&")
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newUrl = oldUrl & qsName & "=" & newValue
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Else
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newUrl = oldUrl & "&" & qsName & "=" & newValue
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End If
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Else
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newUrl = oldUrl & "?" & qsName & "=" & newValue
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End If
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End If
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Return newUrl
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End Function
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Here is an example:
We have the querystring
- http://www.yourdomain.com/search.aspx?fulltext=cat&author=bill+nye&type=scientist&age=45
Now I want to change the "fulltext" to "dog" and the "author" to "bob dole"
Also, I want to remove "type" from the QueryString.
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Dim newUrl = Request.RawUrl.ToString()
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newUrl = ChangeValue(newUrl, "fulltext", "dog")
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newUrl = ChangeValue(newUrl, "author", "bob dole")
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newUrl = ChangeValue(newUrl, "type", "", 1)
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The QueryString would now look like this:
- http://www.yourdomain.com/search.aspx?fulltext=dog&author=bob+dole&age=45
Yes! It's that easy!
