努力从列表中删除项目<T>，尽管我在列表中<T>有一个项目

Question

当用户单击AddToCart按钮时，我试图在List< >中添加项目。最后，当用户单击RemoveFromCart按钮时，我试图从List< >中删除一个项目。最后，我正在努力从List< >中删除该项目。任何人都可以帮帮我。

public partial class Home : System.Web.UI.Page
{
List<int> list1 = new List<int>();
int inc;
protected void listview1_ItemCommand(object sender, ListViewCommandEventArgs e)
{
if (e.CommandName == "Buy")
{
int PC = int.Parse(e.CommandArgument.ToString());
Response.Redirect("~/Buy.aspx?PC=" + PC);
}
if (e.CommandName == "AddToCart")
{
list1.Add(int.Parse(e.CommandArgument.ToString()));
foreach (int i in list1)
{
lbl.Text += i.ToString() + ",";
string length = lbl.Text.Length.ToString();
string sval = lbl.Text.Remove(int.Parse(length) - 1, 1);
lbl1.Text = sval.ToString();
}           
e.Item.FindControl("btnRemoveFromCart").Visible = true;
inc = (int)ViewState["Increment"];
ViewState["Increment"] = inc;
inc += 1;
lblitemscount.Text = inc.ToString();
ViewState["Increment"] = inc;
}
if (e.CommandName == "RemoveFromCart")
{
int val = int.Parse(e.CommandArgument.ToString());
inc = (int)ViewState["Increment"];
ViewState["Increment"] = inc;
inc -= 1;
lblitemscount.Text = inc.ToString();
ViewState["Increment"] = inc;
foreach (int j in list1)
{
if (list1.Contains(val))
{
list1.Remove(val);
}
lbl1.Text += j.ToString();
}
e.Item.FindControl("btnRemoveFromCart").Visible = false;
}
}
}

----------

Answer 1

在循环访问项目时，无法从列表中删除该项目。 您需要找到该项的索引，然后使用RemoveAt方法将其从列表中删除。

https://msdn.microsoft.com/en-us/library/5cw9x18z(v=vs.110(.aspx