Getting user id in detailsview

I would like to show the user details of the logged in user with detailsview.
 In the SQL, I would like to write something like this "select * from aspnet_Users where userId = @userid
 I would like to know how to get the existing user id of the logged in and how to write the sqldatasource
 
</p><p>&nbsp;&lt;asp:SqlDataSource ID="SqlDataSource1" runat="server"
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ConnectionString="&lt;%$ ConnectionStrings:aspnetdbConnectionString %&gt;"
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; SelectCommand="SELECT * FROM [aspnetUsers]"&gt;&lt;/asp:SqlDataSource&gt;</p><p>&nbsp;
 
Thank you.

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