ASP.NET GridView不会更新其行

Question

I followed this tutorial on MSDN for ASP.NET GridView Update Row, but it does not work.

updatedItem.DepartureCity = ((TextBox)(row.Cells[2].Controls[0])).Text;

Still gives the original value from the cell and not the updated one.

public partial class ManagePage : System.Web.UI.Page
{
    BusScheduleModelContainer modelContainer = new BusScheduleModelContainer();
    protected void Page_Load(object sender, EventArgs e)
    {
        //FormsAuthentication.RedirectFromLoginPage()
        //if (!HttpContext.Current.User.Identity.IsAuthenticated)
        //{
        //    Server.Transfer("LoginPage.aspx");
        //}

        resultsGridView.DataSource = modelContainer.BusRoutes.ToList();
        resultsGridView.DataBind();
    }

    protected void RowDeleting(object sender, GridViewDeleteEventArgs e)
    {
        var routeID = int.Parse(e.Values[0].ToString());
        var removedItem = modelContainer.BusRoutes.FirstOrDefault(
            item => item.RouteID == routeID);

        if (removedItem != null)
        {
            modelContainer.BusRoutes.Remove(removedItem);
            resultsGridView.DataSource = modelContainer.BusRoutes.ToList();
            resultsGridView.DataBind();
            modelContainer.SaveChanges();
        }
    }

    protected void RowUpdating(object sender, GridViewUpdateEventArgs e)
    {
        var routeID = int.Parse(e.NewValues[0].ToString());
        var updatedItem = modelContainer.BusRoutes.FirstOrDefault(
            item => item.RouteID == routeID);

        if (updatedItem != null)
        {
            GridViewRow row = resultsGridView.Rows[e.RowIndex];
            var res = row.FindControl("ctl00$ContentPlaceHolder1$resultsGridView$ctl02$ctl03");
            updatedItem.DepartureCity = ((TextBox)(row.Cells[2].Controls[0])).Text;
            updatedItem.ArrivalCity = ((TextBox)(row.Cells[3].Controls[0])).Text;
            updatedItem.DepartureTime = DateTime.Parse(((TextBox)(row.Cells[4].Controls[0])).Text);
            updatedItem.ArrivalTime = DateTime.Parse(((TextBox)(row.Cells[5].Controls[0])).Text);
        }

        resultsGridView.EditIndex = -1;

        BindData();
    }

    protected void RowEditing(object sender, GridViewEditEventArgs e)
    {
        //Set the edit index.
        resultsGridView.EditIndex = e.NewEditIndex;
        //Bind data to the GridView control.
        BindData();
    }

    protected void RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)
    {
        //Reset the edit index.
        resultsGridView.EditIndex = -1;
        //Bind data to the GridView control.
        BindData();
    }

    private void BindData()
    {
        resultsGridView.DataSource = modelContainer.BusRoutes.ToList();
        resultsGridView.DataBind();
    }
}

<div>
                <asp:GridView runat="server" ID="resultsGridView" 
                              AutoGenerateColumns="true" AllowPaging="true"
                              AutoGenerateDeleteButton="true" OnRowDeleting="RowDeleting"
                              AutoGenerateEditButton="true" OnRowUpdating="RowUpdating"
                              OnRowEditing="RowEditing" OnRowCancelingEdit="RowCancelingEdit">
                </asp:GridView>
            </div>

Answer 1

In RowUpdating method you need to add modelContainer.SaveChanges(); like below:

if (updatedItem != null)
{
    GridViewRow row = resultsGridView.Rows[e.RowIndex];
    var res = row.FindControl("ctl00$ContentPlaceHolder1$resultsGridView$ctl02$ctl03");
    updatedItem.DepartureCity = ((TextBox)(row.Cells[2].Controls[0])).Text;
    updatedItem.ArrivalCity = ((TextBox)(row.Cells[3].Controls[0])).Text;
    updatedItem.DepartureTime = DateTime.Parse(((TextBox)(row.Cells[4].Controls[0])).Text);
    updatedItem.ArrivalTime = DateTime.Parse(((TextBox)(row.Cells[5].Controls[0])).Text);
    modelContainer.SaveChanges();
}

Answer 2

Do you use CommandField for update controler? If so, when you click update button, first it will do Page_Load event handler, after that do the implementation in RowUpdating event handler.

You should try to check post back in Page_Load event handler like this:

protected void Page_Load(object sender, EventArgs e)
{  
   if(!IsPostBack)
   {
      resultsGridView.DataSource = modelContainer.BusRoutes.ToList();
      resultsGridView.DataBind();
   }
}

By this way, it will bind data to the GridView only first time you open this page.

For post back event such as clicking update button, it will not bind the original data to GridView again.