How to use result of SqlDataSource query (specified in aspx file) with ButtonField?

Question

I have specified a SelectCommand in SqlDataSource (.aspx file). This SelectCommand query will return data, that will be shown in GridView.

Now there is one property named id (Primary Key) in select command, whose data will NOT be shown on GridView, rather I want to send this 'id' to another page when the respective ButtonField is clicked.

The image above shows GridView. Every column represents activity fields while every row represents a unique activity. The last column has ButtonFields for registering for an activity.

I want to send students to Register For Activity Page along with 'id' of the row clicked. Mind you, value of 'id' is not shown on GridView.

Kindly suggest me a good way to achieve it.

I think one solution could be: Accessing the value of 'id' in backend (.cs) file and then sending id's value through ButtonField Command. but I am not sure if it can be accessed in .cs file?

ASPX code:

<asp:GridView ID="ShowActivitiesGridView" runat="server" AutoGenerateColumns="False" DataSourceID="SqlDataSource1">
            <Columns>
                <asp:BoundField DataField="name" HeaderText="Name" SortExpression="name" />
                <asp:BoundField DataField="location" HeaderText="Location" SortExpression="location" />
                <asp:BoundField DataField="date_of_activity" HeaderText="Date of Activity" SortExpression="date_of_activity" />
                <asp:BoundField DataField="organization" HeaderText="Organization" SortExpression="organization" />
                <asp:BoundField DataField="no_of_student" HeaderText="No of Student" SortExpression="no_of_student" />
                <asp:BoundField DataField="description" HeaderText="Description" SortExpression="description" />
                <asp:ButtonField CommandName="RowCommand" HeaderText="Register For Activity" ShowHeader="True" Text="Register" />
            </Columns>
        </asp:GridView>
        <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:DefaultConnection %>" SelectCommand="SELECT [id], [name], [location], [date_of_activity], [organization], [no_of_student], [description] FROM [Activities]">
        </asp:SqlDataSource>

Answer 1

Replace ButtonField for ItemTemplate on the aspx

    <asp:GridView ID="ShowActivitiesGridView" runat="server" AutoGenerateColumns="False" DataSourceID="SqlDataSource1">
            <Columns>
                <asp:BoundField DataField="name" HeaderText="Name" SortExpression="name" />
                <asp:BoundField DataField="location" HeaderText="Location" SortExpression="location" />
                <asp:BoundField DataField="date_of_activity" HeaderText="Date of Activity" SortExpression="date_of_activity" />
                <asp:BoundField DataField="organization" HeaderText="Organization" SortExpression="organization" />
                <asp:BoundField DataField="no_of_student" HeaderText="No of Student" SortExpression="no_of_student" />
                <asp:BoundField DataField="description" HeaderText="Description" SortExpression="description" />
                <asp:ButtonField CommandName="RowCommand" HeaderText="Register For Activity" ShowHeader="True" Text="Register" />
                <asp:TemplateField HeaderText="Remove" ShowHeader="False">
                  <ItemTemplate>
                    <asp:LinkButton ID="btnRegisterActivity" runat="server" CausesValidation="false" Text="Register For Activity" CommandArgument='<%# Eval("id") %>' oncommand="btnRegisterActivity_Command" />
                  </ItemTemplate>
                </asp:TemplateField>
            </Columns>
        </asp:GridView>
    <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:DefaultConnection %>" SelectCommand="SELECT [id], [name], [location], [date_of_activity], [organization], [no_of_student], [description] FROM [Activities]">
    </asp:SqlDataSource>

on the page cs file

        protected void btnRegisterActivity_Command(object sender, CommandEventArgs e)
        {
            int myId = (int)e.CommandArgument;

            //Do whatever you want
        }