I am trying to get cells from excel into csharp but not sure what's the best variable type to read it into.

If I make the variable a string and the cell value is a double I get a parse error. If I make the variable double then when the cell is a string it wont work.

Here's the code I am running:

 try
 {
        string i = Globals.Sheet1.Cells[7, 7].Value;
        double num;
        if (i == null) return;

        if (double.TryParse(i, out num)) 
        {
              .
              .
              .
        }
}
catch (Exception e)
{
       MessageBox.Show(e.ToString());
}