Create gridview with SQL query when button is clicked?

Question

I am extremely new to ASP.NET and trying to build a basic page in C# for use at work. It basically consists of an execute button that should trigger a query from an external SQL server and display it in a gridview object.

Currently the gridview & query will run on pageload, however as the query can take 2-3 minutes to return (often causing a timeout) I'd rather run the query when a button is clicked.

I imagine the best way is to use it in code behind but am not having any luck with any info found online/in other questions. All the gridview/query is currently in the page directly as below: (SQL has been reduced for example)

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="RecId" DataSourceID="SQLDB01" CellPadding="4" CellSpacing="3" ForeColor="#333333" GridLines="Horizontal" Width="60%">
        <AlternatingRowStyle BackColor="White" />
        <Columns>
            <asp:BoundField DataField="Unit" HeaderText="Scanner" SortExpression="Scanner" />
            <asp:BoundField DataField="Location" HeaderText="PortNo" SortExpression="PortNo" />
            <asp:BoundField DataField="EventDate" HeaderText="EventDate" SortExpression="EventDate" />
        </Columns>
        </asp:GridView>

        <asp:SqlDataSource ID="SQLDB01" runat="server" ConnectionString="<%$ ConnectionStrings:services_dbConnectionString %>" SelectCommand="SELECT TOP 20 * FROM dbo.Event ORDER BY RecId DESC"></asp:SqlDataSource>

How do I a) get the button to trigger all this instead, and b) move it all into code behind if needed?

Answer 1

If you click on Design tab under your programming window in visual studio, you can see a visual representation of your button. Double clicking on this will automatically create a click Method for that button in your .cs file. You can write code to populate the button from the database inside that Method. You will need to write it in C#.