I am building a online shop for a school project and I came across this problem when I reached the adding product to cart of an item part. It doesn't shows any error is visual studio but when i run in the web browser it doesn't it work and it shows this error, I am trying to get the ProductID of my items in my productlist and I think there is something wrong in that part, Sys.WebForms.PageRequestManagerServerErrorException: Object reference not set to an instance of an object.****strong text
Im new to ASP.Net so please help me
This my Code behind code:
string ProductID = Convert.ToInt32((((Button)sender).CommandArgument)).ToString();
string ProductQuantity = "1";
DataListItem currentItem = (sender as Button).NamingContainer as DataListItem;
Label lblavailablestock = currentItem.FindControl("lblavailablestock") as Label;
if (Session["MyCart"] != null)
{
DataTable dt = (DataTable)Session["MyCart"];
var checkproduct = dt.AsEnumerable().Where(r => r.Field<string>("ProductID")== ProductID);
if(checkproduct.Count() == 0)
{
string query = "select * from Products where ProductID = " + ProductID + "";
DataTable dtproducts = GetData(query);
DataRow dr = dt.NewRow();
dr["ProductID"] = ProductID;
dr["Name"] = Convert.ToString(dtproducts.Rows[0]["Name"]);
dr["Description"] = Convert.ToString(dtproducts.Rows[0]["Description"]);
dr["Price"] = Convert.ToString(dtproducts.Rows[0]["Price"]);
dr["ImageUrl"] = Convert.ToString(dtproducts.Rows[0]["ImageUrl"]);
dr["ProductQuantity"] = ProductQuantity;
dr["AvailableStock"] = lblavailablestock.Text;
dt.Rows.Add(dr);
Session["MyCart"] = dt;
lblitems.Text = dt.Rows.Count.ToString();
}
}
else
{
string query = "select * from Products where ProductID = " + ProductID + "";
DataTable dtproducts = GetData(query);
DataTable dt = new DataTable();
dt.Columns.Add("ProductID", typeof(string));
dt.Columns.Add("Name", typeof(string));
dt.Columns.Add("Description", typeof(string));
dt.Columns.Add("Price", typeof(string));
dt.Columns.Add("ImageUrl", typeof(string));
dt.Columns.Add("ProductQuantity", typeof(string));
dt.Columns.Add("AvailableQuantity", typeof(string));
DataRow dr = dt.NewRow();
dr["ProductID"] = ProductID;
dr["Name"] = Convert.ToString(dtproducts.Rows[0]["Name"]);
dr["Description"] = Convert.ToString(dtproducts.Rows[0]["Description"]);
dr["Price"] = Convert.ToString(dtproducts.Rows[0]["Price"]);
dr["ImageUrl"] = Convert.ToString(dtproducts.Rows[0]["ImageUrl"]);
dr["ProductQuantity"] = ProductQuantity;
dr["AvailableStock"] = lblavailablestock.Text;
dt.Rows.Add(dr);
Session["MyCart"] = dt;
}
My source code:
<asp:Button ID="btnaddtocart" runat="server" Text="Add to cart" OnClick="btnaddtocart_Click" CommandArgument='<%# Bind("ProductID") %>'/>
