I get LINQ to Entities Int32 ToInt32(System.String) when convert

I get LINQ to Entities Int32 ToInt32(System.String) when convert.i tried int.Parse() , SqlFunction and EdmFunction but the problem still going on.

Exception:

System.NotSupportedException: LINQ to Entities does not recognize the method 'Int32 ToInt32(System.String)' method, and this method cannot be translated into a store expression

Code:

try
    {
        ModelEntities me = new ModelEntities();
        var query = from p in me.Products
                    join c in me.ProductCategories
                    on Convert.ToInt32(p.CategoryId) equals c.CategoryId
                    select new
                    {
                        p.ProductTitle,
                        c.CategoryName
                    };
        rptProducts.DataSource = query;
        rptProducts.DataBind();
    }
    catch (Exception ex)
    {
        Response.Write(ex.Message);
    }