Help With Query Strings

I am using query strings to pass data from web form to web form and I have two questions.  First if i use a asp:sqldatasouce to fill up a grid view and I have my select command set to a paramater that get whatever is in the query string it will not work because whatever is in the quers string gets a " ' " put in front and in the back of it.  So if the query string was 5 whene it does the sql statement it sets my paramater = '5' not just 5 so its wont work.  How can I fix this using the asp:sql datasource my aspx code looks like

<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:Rental PropertiesConnectionString %>"

SelectCommand="SELECT * FROM [APARTMENTS] WHERE ([PROPERITY_ID] = @PROPERITY_ID)">

<SelectParameters>

<asp:QueryStringParameter Name="PROPERITY_ID" QueryStringField="key" Type="Int32" />

</SelectParameters>

</asp:SqlDataSource>

Also since i have not been able to get around this so i have been wrting code in vb.net to attact a dataset to a grid view to populate it based on the query string i would do the following in vb.net to get ride of the ' in front and behind the query string

Dim y as string  = "'" // " ' "

key = Request.QueryString("key").trim(y.tochararray)

But now i am doing another project in C# and I have re-written the above code in C# it will run but it will not take the " ' " out form infront or behind key.  How does this need to be changed up?

string y = "'";

key = Request.QueryString["key"].trim(y.tochararray());