Question

I’m passing a value thru a querystring, I want that value to be part of my selectcommand to build my GridView. But I’m getting the following error. Any ideas how to fix?

Error: Conversion failed when converting the nvarchar value ‘<%=QueryString2%>’ to data type int.

C#:

    protected void Page_Load(object sender, EventArgs e)
    {
        QueryString=Convert.ToInt32(Request.QueryString["tourid"]);
    }

    private int _querystring;

    public int QueryString
    {
        get
        {
            return _querystring;
        }
        set
        {
            _querystring = value;
        }
    }

ASPX:

        <asp:SqlDataSource ID="SqlDataSource1" runat="server" 
            ConnectionString="<%$ ConnectionStrings:ChinatowndbConnString %>" 
            SelectCommand="SELECT * FROM [vwSchedule] Where TourId=@tid">

            <SelectParameters>
                <asp:Parameter  DefaultValue="<%=QueryString%>" Name="tid" />
            </SelectParameters>
        </asp:SqlDataSource>

Answer 1

You can’t use <%= ... %> to assign the value of a server-control property. As a result, your DefaultValue is being set to the literal string "<%=QueryString%>", which is not a valid integer.

Try using a QueryStringParameter instead:

<SelectParameters>
   <asp:QueryStringParameter  
      Name="tid" 
      DbType="Int32" 
      QueryStringField="tourid"
   />
</SelectParameters>