Must declare the scalar variable "@vendor"

Question

    <asp:SqlDataSource ID="SqlDataSource3" runat="server" ConnectionString="<%$ ConnectionStrings:IS315Database1ConnectionString %>" SelectCommand="SELECT Category.CategoryName, Product.ProductName, Product.ProductPrice, Product.ProductID, vendor.VendorID, vendor.VendorName FROM vendor INNER JOIN Product ON vendor.VendorID = Product.VendorID INNER JOIN Category ON Product.CategoryID = Category.CategoryID WHERE ([VendorID] = @vendor.VendorID)">
        <SelectParameters>
            <asp:ControlParameter ControlID="DropDownList1" Name="VendorID" PropertyName="SelectedValue" Type="String" />
        </SelectParameters>
    </asp:SqlDataSource>

So I'm nearly 100% my error is coming from the end of the first line of code "WHERE ([VendorID] = @vendor.VendorID)"> "

Does anyone know how to fix this, I've seen a couple of the same questions involving scalars, none have fixed or I haven't been able to throw my situation in the same context. Thank you.

Did you declare `@vendor`? – Juan Carlos Oropeza Apr 07 '17 at 18:35 — Juan Carlos Oropeza, Apr 07 '17 at 18:35
I'm pretty sure I did, vendor is my vendor table – DataStructors23 Apr 07 '17 at 19:26 — DataStructors23, Apr 07 '17 at 19:26

Lukasz M · Accepted Answer · 2017-04-07T21:45:30.023

It seems that the issue is caused by lack of @vendor parameter declaration, as Juan Carlos Oropeza suggested in his comment. You rejected his suggestion, but after analysing the code I got into the same conclusion, so I decided to post more explanatory answer.

You used @vendor parameter in the query, but declared only @VendorID parameter (unless You declare other parameters somewhere else).

When You declare ControlParameter, the Name property indicates the name of parameter used in the query. In the code You posted, the parameter is named VendorID, so this name should be used in the query as well (with an additional @ character that indicates it's a parameter's name).

Try to change the end of the query to WHERE [VendorID] = @VendorID.

For more information, take a look at:

Must declare the scalar variable "@vendor"

1 Answers1