C# 购物车显示记录两次_C#_Asp.net_Ado.net

C# 购物车显示记录两次

c# asp.net

C# 购物车显示记录两次,c#,asp.net,ado.net,C#,Asp.net,Ado.net,问题是，当同一物品再次添加到购物车时，它会显示同一产品的同一记录两次，这里我希望当我按两次或三次添加到购物车按钮时，它应该是同一物品的增量数量 protected void AddToCartButton_Click(object sender, EventArgs e) { if (con.State == ConnectionState.Open) { con.Close(); } con.Open(); SqlCommand cmd

问题是，当同一物品再次添加到购物车时，它会显示同一产品的同一记录两次，这里我希望当我按两次或三次添加到购物车按钮时，它应该是同一物品的增量数量

protected void AddToCartButton_Click(object sender, EventArgs e)
{
    if (con.State == ConnectionState.Open)
    {
        con.Close();
    }
    con.Open();
    SqlCommand cmd = con.CreateCommand();
    cmd.CommandType = CommandType.Text;
    book_id = Convert.ToInt32(Request.QueryString["book_id"].ToString());
    cmd.CommandText = "select * from Book where book_id = " + book_id + "";
    cmd.ExecuteNonQuery();
    DataTable dt = new DataTable();
    SqlDataAdapter sda = new SqlDataAdapter(cmd);
    sda.Fill(dt);
    foreach (DataRow dr in dt.Rows)
    {                 
        //book_id =Convert.ToInt32(dr["book_id"]);
        title = dr["title"].ToString();
        //quantity = dr["quantity"].ToString();
        quantity = QuantityTxt.Text;
        price = dr["price"].ToString();
    }
    //Restrict User to enter some quantity that he wants...
    if(Convert.ToInt32(QuantityTxt.Text)>Convert.ToInt32(quantity))
    {
        ErrorMsglbl.Text = "Please Enter Lower Quantity";
    }
    else
    {
        ErrorMsglbl.Text = "";
    }
    // Creating Cookies to store the value and then i will assign to data table... 

    if (Request.Cookies["ShoppingCart"] == null)
    {
        Response.Cookies["ShoppingCart"].Value = book_id.ToString() + "," + title.ToString() + "," + quantity.ToString() + "," + price.ToString();
        Response.Cookies["ShoppingCart"].Expires = DateTime.Now.AddDays(1);
    }
    else
    {
        Response.Cookies["ShoppingCart"].Value = Request.Cookies["ShoppingCart"].Value + "|" + book_id.ToString() + "," + title.ToString() + "," + quantity.ToString() + "," + price.ToString();
        Response.Cookies["ShoppingCart"].Expires = DateTime.Now.AddDays(1);
    }

    Response.Redirect("BookDetails.aspx?book_id="+book_id.ToString()+"&Cat_ID="+ViewState["cat"]+"");

}// End Add To Cart Button...

问题在于else块

 Response.Cookies["ShoppingCart"].Value = Request.Cookies["ShoppingCart"].Value + 
"|" + book_id.ToString() + "," + title.ToString() + 
"," + quantity.ToString() + "," + price.ToString();

在这里，您将以前的cookie值与新内容一起分配给新cookie。例如，如果您的饼干中有“1，Shoe，1,25”，并且再次将相同的产品添加到购物车中，您将得到类似“1，Shoe，1,25 | 1，Shoe，1,25”的内容

这个问题可以通过多种方法解决

拆分cookies并检查book\u id值

使用对象存储购物车项目并在会话中保存它们

先接近

String[] carts = Request.Cookies["ShoppingCart"].Value.Split("|")
bool bookIdExists = false;
foreach(string cartDetail in carts)
{
  string  bookId = cartDetail.Split(",")[0];
  if(bookId == newBookId)
  {
    bookIdExists = true;
  }
}
if(!bookIDExists)
{
  //Add your new item to Cookie
}

第二种方法

public Class Cart
{
  public int BookId {get; set;}
  public string Title {get; set;}
  public int Qty {get; set;}
  public decimal Price {get; set}
}

List<Cart> carts =Session["Cart"]==null? new List<Cart>(): Session["Cart"] as List<Cart>;
var existingCart = carts.Where(x=> x.BookId==newBookId).FirstOrDefault();
if(existingCart==null)
{
  Cart c= new Cart {
  BookId = newBookId,
  Title =newTitle,
  Qty = newQty,
  Price =newPrice
};
 carts.Add(c);
 Session["Cart"] = carts;
}

公共类购物车
{
public int BookId{get；set；}
公共字符串标题{get；set；}
公共整数数量{get；set；}
公共十进制价格{get；set}
}
列表购物车=会话[“购物车”]==空？新建列表（）：会话[“购物车”]作为列表；
var existingCart=carts.Where（x=>x.BookId==newBookId.FirstOrDefault（）；
如果（existingCart==null）
{
购物车c=新购物车{
BookId=newBookId，
标题=新标题，
数量=新数量，
价格=新价格
};
添加（c）；
会话[“购物车”]=购物车；
}

你可以用更好的方法来解决这个问题

但使用cookie来存储购物车的详细信息是个糟糕的主意