GridView strange behaviour - asp.net

Question

I have problem on page bellow, in gdvCar_DataBound I add three buttons, when I click on any of them, page go to postback but doesn't enter in gdvCar_RowCommand and then that buttons ( and images that I also add in gdvCar_DataBound) disaper. Grid is then full like gdvCar_DataBound isn't execute. My question is why it doesn't enter at gdvCar_RowCommand ?
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using HMS.library;
using System.Data.SqlClient;
namespace HMS
{
public partial class Cars : System.Web.UI.Page
{
#region fields
private const Int16 PageId = 1;
private String connectionString = "Server=localhost;Database=hms_test;Trusted_Connection=True;";
String[] filters = null;
#endregion
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
FillProducer();
FillModel(Convert.ToInt16(ddlProducer.SelectedValue));
RestoreFilters();
FillGrid();
}
}
#region events
protected void ddlProducer_Changed(object sender, EventArgs e)
{
if (ddlProducer.SelectedValue != "0")
{
ddlModel.Enabled = true;
FillModel(Convert.ToInt16(ddlProducer.SelectedValue));
}
else
{
ddlModel.SelectedValue = "0";
ddlModel.Enabled = false;
}
upSearch.Update();
}
protected void gdvCar_RowCommand(object sender, GridViewCommandEventArgs e)
{
switch (e.CommandName)
{
case "Reserve":
{
pnlReserve.Visible = true;
break;
}
case "Phone":
{
break;
}
case "Email":
{
break;
}
}
}
protected void gdvCar_DataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
String id = e.Row.Cells[0].Text;
Image img = new Image();
img.ID = "img_one" + id;
img.Width = 96;
img.Height = 96;
img.ImageUrl = "images/car/" + e.Row.Cells[7].Text;
e.Row.Cells[7].Controls.Add(img);
img = new Image();
img.ID = "img_two" + id;
img.Width = 96;
img.Height = 96;
img.ImageUrl = "images/car/" + e.Row.Cells[8].Text;
e.Row.Cells[8].Controls.Add(img);
img = new Image();
img.ID = "img_three" + id;
img.Width = 96;
img.Height = 96;
img.ImageUrl = "images/car/" + e.Row.Cells[9].Text;
e.Row.Cells[9].Controls.Add(img);
ImageButton imbReserve = new ImageButton();
imbReserve.ID = "res" + id;
imbReserve.Enabled = true;
imbReserve.Width = 48; imbReserve.Height = 48;
imbReserve.ToolTip = "Reserve"; imbReserve.AlternateText = "Reserve";
imbReserve.ImageUrl = "images/icons/key.gif";
imbReserve.CommandName = "Reserve";
imbReserve.CommandArgument = id;
e.Row.Cells[10].Controls.Add(imbReserve);
ImageButton imbPhone = new ImageButton();
imbPhone.ID = "phone" + id;
imbPhone.Enabled = true;
imbPhone.Width = 48; imbPhone.Height = 48;
imbPhone.ToolTip = "Reserve by phone"; imbPhone.AlternateText = "Phone";
imbPhone.ImageUrl = "images/icons/phone.jpg";
imbPhone.CommandName = "Phone";
imbPhone.CommandArgument = id;
e.Row.Cells[11].Controls.Add(imbPhone);
ImageButton imbEmail = new ImageButton();
imbEmail.ID = "email" + id;
imbEmail.Enabled = true;
imbEmail.Width = 48; imbEmail.Height = 48;
imbEmail.ToolTip = "Reserve by email"; imbEmail.AlternateText = "Email";
imbEmail.ImageUrl = "images/icons/email.jpg";
imbEmail.CommandName = "Email";
imbEmail.CommandArgument = id;
e.Row.Cells[12].Controls.Add(imbEmail);
}
}
protected void imbSearch_Click(object sender, ImageClickEventArgs e)
{
StoreFilters();
FillGrid();
}
#endregion
#region functions
private void FillProducer()
{
hmsDataContext hms = new hmsDataContext();
var source = from o in hms.producer_cars
orderby o.name
select new
{
o.id,
o.name
};
foreach (var temp in source)
ddlProducer.Items.Add(new ListItem(temp.name, temp.id.ToString()));
ddlProducer.Items.Insert(0, (new ListItem("all producers", "0")));
}
private void FillModel(int producer_id)
{
hmsDataContext hms = new hmsDataContext();
var source = from o in hms.model_cars
from p in hms.producer_cars
where o.producer_car_id == producer_id && p.id == producer_id
orderby o.name
select new
{
o.id,
o.name
};
ddlModel.Items.Clear();
foreach (var temp in source)
ddlModel.Items.Add(new ListItem(temp.name, temp.id.ToString()));
ddlModel.Items.Insert(0, (new ListItem("all producers", "0")));
}
private void FillGrid()
{
SqlConnection conn = new SqlConnection(connectionString);
String command = #"SELECT car.id AS id, car.price as price, car.weight as weight,
car.year as year, producer_car.name as producer, model_car.name as model, car.number_seats as number_seats, car.photo_one as photo_one,car.photo_two as photo_two,car.photo_three as photo_three, '' as reserver,'' as phone,'' as email
FROM car INNER JOIN model_car on car.model_car_id=model_car.id
INNER JOIN producer_car on model_car.producer_car_id=producer_car.id";
if(filters!=null){
String[] search=new String[5];
search[0]=filters[0]!="0"?"producer_car.id="+filters[0]:"";
search[1]= filters[1] != "0" ? "model_car.id=" + filters[1] : "";
search[2]=filters[2]!=""?"car.color LIKE \'"+filters[2]+"\'":"";
search[3]=filters[3]!=""?"car.price<"+filters[3]:"";
search[4] = filters[4] != "" ? "car.number_seats=" + filters[4] : "";
var a=from f in search
where f!=""
select f;
String filterAddition="";
if(a.Count()>0){
filterAddition=" WHERE ";
foreach ( var b in a){
filterAddition+=" "+b+" AND";
}
filterAddition=filterAddition.EndsWith("AND")?filterAddition.Substring(0,filterAddition.Length-3):filterAddition;
}
command+=filterAddition;
}
SqlCommand comm = new SqlCommand(command, conn);
SqlDataReader r = null;
try
{
comm.Connection.Open();
r =comm.ExecuteReader();
gdvCar.DataSource = r;
gdvCar.DataBind();
r.Close();
}
catch (Exception exc)
{
throw (exc);
}
finally
{
conn.Close();
}
}
private void StoreFilters()
{
filters = new String[5];
filters[0] = ddlProducer.SelectedValue;
filters[1] = ddlModel.SelectedValue;
filters[2] = ddlColor.SelectedValue;
filters[3] = txtStartPrice.Text;
filters[4] = ddlNumber.SelectedValue;
Session["1"] = filters;
}
private void RestoreFilters()
{
if (Session["1"] != null)
{
filters = (String[])Session["1"];
ddlProducer.SelectedValue = filters[0];
ddlProducer_Changed(null, null);
ddlModel.SelectedValue = filters[1];
ddlColor.SelectedValue = filters[2];
txtStartPrice.Text = filters[3];
ddlNumber.SelectedValue = filters[4];
}
}
private void ReserveCar(String FirstName, String LastName, DateTime Start, DateTime End, String Visa, Int16 CarId)
{
hmsDataContext hms = new hmsDataContext();
var a = from c in hms.cars
from rc in hms.rented_cars
where c.id == rc.id_car && c.id == CarId
select new
{
start = rc.start,
end = rc.end
};
Boolean free = false;
if (a.Count() == 0)
{
free = true;
}
else if (a.Count() == 1)
{
if ((a.First().start > End) || (a.First().end < Start))
free = true;
}
else
{
if ((a.First().start > End) || (a.First().end < Start))
free = true;
else if(!free)
{
int n = a.Count();
for (int i = 0; (i < n - 1) && (!free); i++)
{
if (a.ElementAt(i).end < Start && a.ElementAt(i + 1).start > End)
free = true;
i++;
}
if (!free)
{
if (a.ElementAt(n - 1).end < Start)
free = true;
}
}
}
if (free)
{
//insert
}
else
{
//label-nije slobodno za taj termin
}
}
#endregion
}
}
aspx
<%# Page Language="C#" AutoEventWireup="true" CodeBehind="Cars.aspx.cs" Inherits="HMS.Cars"
MasterPageFile="~/frame.Master" %>
<%# Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="asp" %>
<asp:Content ContentPlaceHolderID="content" ID="con" runat="server">
<link rel="StyleSheet" href="css/menu.css" type="text/css" media="all">
<asp:ScriptManager ID="sc" runat="server">
</asp:ScriptManager>
<div id="menu">
<ul class="glossymenu">
<li><b>Home</b></li>
<li class="current"><b>Cars</b></li>
<li><b>Boats</b></li>
<li><b>Contact</b></li>
<li><b>Admin</b></li>
</ul>
</div>
<div>
<div>
<asp:UpdatePanel ID="upSearch" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<div id="search">
<fieldset>
<legend>Advanced search</legend>
<table>
<tr>
<td>
Proizvođač:<asp:DropDownList ID="ddlProducer" runat="server" OnSelectedIndexChanged="ddlProducer_Changed"
AutoPostBack="true">
</asp:DropDownList>
</td>
<td>
Model:<asp:DropDownList ID="ddlModel" runat="server" Enabled="false">
</asp:DropDownList>
</td>
<td>
Boja:<asp:DropDownList ID="ddlColor" runat="server">
<asp:ListItem Text="all" Value=""></asp:ListItem>
<asp:ListItem Text="White" Value="white"></asp:ListItem>
<asp:ListItem Text="Green" Value="green"></asp:ListItem>
<asp:ListItem Text="White" Value="white"></asp:ListItem>
<asp:ListItem Text="Green" Value="green"></asp:ListItem>
<asp:ListItem Text="White" Value="white"></asp:ListItem>
<asp:ListItem Text="Green" Value="green"></asp:ListItem>
<asp:ListItem Text="White" Value="white"></asp:ListItem>
<asp:ListItem Text="Green" Value="green"></asp:ListItem>
<asp:ListItem Text="White" Value="white"></asp:ListItem>
<asp:ListItem Text="Green" Value="green"></asp:ListItem>
<asp:ListItem Text="White" Value="white"></asp:ListItem>
<asp:ListItem Text="Green" Value="green"></asp:ListItem>
</asp:DropDownList>
</td>
<td>
Cena do:
<asp:TextBox ID="txtStartPrice" runat="server" MaxLength="10"></asp:TextBox>
din/dan
</td>
<td>
Number seats:<asp:DropDownList ID="ddlNumber" runat="server">
<asp:ListItem Text="-- --" Value=""></asp:ListItem>
<asp:ListItem Text="1" Value="1"></asp:ListItem>
<asp:ListItem Text="2" Value="2"></asp:ListItem>
<asp:ListItem Text="3" Value="3"></asp:ListItem>
<asp:ListItem Text="4" Value="4"></asp:ListItem>
<asp:ListItem Text="5" Value="1"></asp:ListItem>
<asp:ListItem Text="6" Value="2"></asp:ListItem>
<asp:ListItem Text="7" Value="3"></asp:ListItem>
<asp:ListItem Text="8" Value="4"></asp:ListItem>
<asp:ListItem Text="9" Value="2"></asp:ListItem>
<asp:ListItem Text="10" Value="3"></asp:ListItem>
<asp:ListItem Text="11" Value="4"></asp:ListItem>
</asp:DropDownList>
</td>
<td>
<asp:ImageButton ID="imbSearch" runat="server" ImageUrl="images/icons/search.png"
Width="32" Height="32" ToolTip="Search by choosen criterions" AlternateText="Search"
OnClick="imbSearch_Click" />
</td>
</tr>
</table>
</fieldset>
</div>
</ContentTemplate>
</asp:UpdatePanel>
<br />
<br />
<div>
<asp:UpdatePanel ID="upGrid" runat="server" UpdateMode="Always">
<ContentTemplate>
<asp:GridView ID="gdvCar" runat="server" OnRowCommand="gdvCar_RowCommand"
OnRowDataBound="gdvCar_DataBound">
</asp:GridView>
</ContentTemplate>
</asp:UpdatePanel>
</div>
<div>
<asp:UpdatePanel ID="upTemp" runat="server"><ContentTemplate>
<asp:Panel ID="pnlReserve" runat="server" Visible="false" Width="400" Height="400">
<asp:UpdatePanel ID="upReserve" runat="server">
<ContentTemplate>
</ContentTemplate>
</asp:UpdatePanel>
</asp:Panel>
</ContentTemplate></asp:UpdatePanel>
</div>
</div>
</asp:Content>

Answer 1

You have to recreate the buttons in RowCreated on every Postback, otherwise their events won't fire.
Save what you need in RowDataBound in the ViewState. In the RowCreated recreate them on Postback(RowDatabound will only be called on Databinding) based on the Viewstate value. Then all controls are available in early page-lifecyle to raise their events.

Answer 2

I believe you can do it in a more elegant way, take a look,
<asp:GridView ...>
<Columns>
<asp:BoundField HeaderText="Some Caption" DataField="Column name from the DataReader result"/>
...
<asp:TemplateField HeaderText="Image..">
<asp:Image runat="server" ImageUrl='<%# String.Format("images/car/{0}", Eval("The column name from the DataReader of the cell 7") %>' />
</asp:TemplateField>
<asp:TemplateField HeaderText="ImageButton..">
<asp:ImageButton runat="server" .../>
</asp:TemplateField>
</Columns>
</asp:GridView>
Then you don't have to add the buttons and the images in the code and takecare of adding them each time the row is created, you just need to fetch the data from the database and set the DataSource of the gridview, and I think you can also get rid of the code fetching the data and replace it with a SqlDataSource.
Take a look at this article about the GridView,
http://msdn.microsoft.com/en-us/library/aa479353.aspx