Casting an aspx page as a Previous Page

[g3000]

What else is needed in this code snippet in order for SelectProject to
be accessible.

class SelectProject is defined in the same project as this code
snippet.
The compiler is saying Im missing a using or assembly reference.

Any ideas?

protected void Page_Load(object sender, EventArgs e)
{
SelectProject prevPage = PreviousPage as SelectProject;
//if previouspage exist then check for parameter values
if (PreviousPage != null)
{
// Add the chart data from the database based on select
param
if (prevPage != null)
{

Chart1.SeriesCollection.Add(GetChartData(prevPage.ProjectCode,
prevPage.LaborCode));
}
}
<snip>