Selectcommand with variable

[djohnson]

Hello, I'm wondering why a variable in my selectcommand is not
working.

In Page_Load I have this:

String current_user = User.Identity.Name;
Response.Write(current_user); // verified the string 'djohnson' is
present

But this errors out in the Body ('No value given for one or more
required parameters'):
<asp:AccessDataSource id="AccessDataSource1" runat="server" DataFile =
"upload.mdb" SelectCommand="Select * from Customers WHERE
Login=@current_user"/>

This, however, works:
<asp:AccessDataSource id="AccessDataSource1" runat="server" DataFile =
"upload.mdb" SelectCommand="Select * from Customers WHERE
Login='djohnson'"/>


This is very confusing.... !

 

[Nicholas Paldino [.NET/C# MVP]]

djohnson,

The AccessDataSource has no way of knowing how to access your local
variables. If you want to parameterize your query, you will need to place
extra tags in your AccessDataSource tag indicating the parameter type.

Then, in your code, you would get the AccessDataSource instance and then
set the values in the parameters returned by the SelectParameters property.

Hope this helps.

 

[djohnson]

I can't just use a session variable?

Anyway, I looked at the link,
http://msdn2.microsoft.com/en-us/library/system.web.ui.webcontrols.parametercollection.aspx.

Based on this technique would I need to setup a hidden field in which
to keep the username string?

 

[Nicholas Paldino [.NET/C# MVP]]

djohnson,

Well, you would have to use the appropriate tag in the AccessDataSource
to set up the parameter value. If you want to get the value from the
session, then you have to use the SessionParameter tag.

 

[djohnson]

That works.

So I put this is page_load:
Session["username"] = User.Identity.Name;

And setup the data source like this:
<asp:AccessDataSource id="AccessDataSource1" runat="server" DataFile
= "secretinfo.mdb" SelectCommand="Select * from Customers WHERE
Login=?">
<SelectParameters>
<asp:SessionParameter
Name="username"
SessionField="username"
DefaultValue="" />
</SelectParameters>
</asp:AccessDataSource>


Thanks!