Develop Reference

Get data loaded from sql on Page_Load

I'm noobie to this :)
I'm getting data from SQL Server in the page_load event handler, and that works fine with SqlDataReader.
I also added a DataTable. I want to use the data when selecting a dropdownlist.
This is my code:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
string mainconn1 = ConfigurationManager.ConnectionStrings["SqlConnection1"].ConnectionString;
SqlConnection sqlconn1 = new SqlConnection(mainconn1);
string Sqlquery1 = "SELECT p.[Name], m.machineid,md.MachineNumber, md.HostName FROM [db].[dbo].[Machine] m INNER JOIN MachineDevice md ON md.MachineID = m.MachineID INNER JOIN property p ON m.PropertyID = p.PropertyID WHERE ([status] = '1') AND (md.DateTimeRetired IS NULL) ORDER BY md.MachineNumber";
SqlCommand sqlcomm1 = new SqlCommand(Sqlquery1, sqlconn1);
sqlconn1.Open();
SqlDataReader rd1 = sqlcomm1.ExecuteReader();
DataTable dt = new DataTable();
dt.Load(rd1);
}
}
And this:
protected void Ort_SelectedIndexChanged1(object sender, EventArgs e)
{
if (Ort.SelectedValue == "Stockholm")
{
// while (rd1.read)
// {
// Machine.DataSource = rd1;
// Machine.DataTextField = "MachineNumber";
// Machine.DataValueField = "MachineNumber";
// Machine.DataBind();
// Machine.Items.Insert(0, new ListItem("-Select Machine-", "0"));
// }
}
}
Is it possible to get data when selectindexchanged, or do I need to ask SQL Server again?
Thanks

Sure, say we have a drop down (combo box) of some cities, and when you select the city, we fill out a gird of hotels.
Is it possible to get data when selectindexchanged, or do I need to ask SQL Server again?
you could in some cases "persist" the data, but the cost is just as high as in most cases hitting the database again.
so, yes, it is standard fair to re-pull that data.
example:
this markup:
<h3>Select Hotel city</h3>
<asp:DropDownList ID="DropDownList1" runat="server"
Width="150px" Height="30px"
DataTextField="City"
AutoPostBack="true"
OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged">
</asp:DropDownList>
<br />
<br />
<asp:GridView ID="GVHotels" runat="server" CssClass="table table-hover"
DataKeyNames="ID" AutoGenerateColumns="false" Width="40%" OnRowDataBound="GVHotels_RowDataBound" >
<Columns>
<asp:BoundField DataField="FirstName" HeaderText="First Name" HeaderStyle-Width="100" />
<asp:BoundField DataField="LastName" HeaderText="Last Name" HeaderStyle-Width="100" />
<asp:BoundField DataField="HotelName" HeaderText="Hotel Name" HeaderStyle-Width="120"/>
<asp:BoundField DataField="City" HeaderText="City" />
<asp:BoundField DataField="Description" HeaderText="Province" />
<asp:TemplateField>
<ItemTemplate>
<button runat="server" id="cmdEditBooking"
type="button" class="btn myshadow"
onserverclick="cmdEditBooking_ServerClick">
<span class="glyphicon glyphicon-home"></span>View
</button>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
So, we have a combo box (dropdown list) of city to select, and then we display hotels from that city.
Code behind:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
LoadCombo();
}
void LoadCombo()
{
string strSQL = "SELECT City FROM City ORDER BY City";
SqlCommand cmdSQL = new SqlCommand(strSQL);
DropDownList1.DataSource = MyRstP(cmdSQL);
DropDownList1.DataBind();
DropDownList1.Items.Insert(0, new ListItem("Select City", ""));
}
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
if (DropDownList1.SelectedIndex >0)
{
string strSQL =
#"SELECT * FROM tblHotelsA
WHERE City = #City
ORDER BY HotelName";
SqlCommand cmdSQL = new SqlCommand(strSQL);
cmdSQL.Parameters.Add("#City", SqlDbType.NVarChar).Value = DropDownList1.Text;
GVHotels.DataSource = MyRstP(cmdSQL);
GVHotels.DataBind();
}
}
And both of above use this handy helper routine:
DataTable MyRstP(SqlCommand cmdSQL)
{
DataTable rstData = new DataTable();
using (SqlConnection conn = new SqlConnection(Properties.Settings.Default.TEST4))
{
using (cmdSQL)
{
cmdSQL.Connection = conn;
conn.Open();
rstData.Load(cmdSQL.ExecuteReader());
}
}
return rstData;
}
So, result:

2 drop down list and calendar to display gridview in C#

I have simple booking ticketing system for my school project and am using windows form in asp.net. i have simple search where the person can input bickup, drop off and date. am using drop down list FOR bickup and dropoff and date normal calendar attached to text box. but i can't populate the gridview e.g bus rides available from one position to another in specific dates , like from A to B in 24 of August. my date i stored as date others Nvarchar. i can bind the drop down list but the search button shows nothing.
below is my front code and back-end code. please i need help am new to c# and coding in general.
<form id="form1" runat="server">
<div>
<asp:TextBox ID="tbdates" runat="server"></asp:TextBox>
<asp:Button ID="Button2" runat="server" OnClick="Button2_Click" Text="Button" />
<asp:DropDownList ID="DropDownList1" runat="server">
</asp:DropDownList>
<asp:DropDownList ID="DropDownList2" runat="server">
</asp:DropDownList>
</div>
<asp:Calendar ID="Calendar1" runat="server" OnSelectionChanged="Calendar1_SelectionChanged"></asp:Calendar>
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"
CssClass="table table-hover table-striped">
<Columns>
<asp:BoundField DataField="BusNo" HeaderText="Bus Number" />
<asp:BoundField DataField="date" HeaderText="Date" />
<asp:BoundField DataField="Time" HeaderText="Time" />
<asp:BoundField DataField="Bickup" HeaderText="Bick Up" />
<asp:BoundField DataField="DropOff" HeaderText="Drop Off" />
<asp:BoundField DataField="Fare" HeaderText="Fare" />
</Columns>
<HeaderStyle BackColor="#33CCFF" />
</asp:GridView>
<asp:Button ID="Button1" runat="server" Text="Button" />
<br />
</form>
public partial class DriverDisplay : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
fill_DropDownList1();
fill_DropDownList2();
}
}
private void fill_DropDownList1()
{
try
{
SqlConnection con2 = new SqlConnection(ConfigurationManager.ConnectionStrings["MyDatabase1ConnectionString"].ConnectionString);
string sql = "SELECT * FROM Ticket";
SqlCommand cmd = new SqlCommand(sql, con2);
SqlDataAdapter adapter = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
adapter.Fill(dt);
DropDownList1.DataSource = dt;
DropDownList1.DataTextField = "Bickup";
DropDownList1.DataValueField = "Bickup";
DropDownList1.DataBind();
}
catch (Exception)
{
}
}
private void fill_DropDownList2()
{
try
{
SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["MyDatabase1ConnectionString"].ConnectionString);
string sql = "SELECT * FROM Ticket";
SqlCommand cmd = new SqlCommand(sql, con);
SqlDataAdapter adapter = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
adapter.Fill(dt);
DropDownList2.DataSource = dt;
DropDownList2.DataTextField = "Dropoff";
DropDownList2.DataValueField = "DropOff";
DropDownList2.DataBind();
}
catch (Exception)
{
}
}
protected void Button2_Click(object sender, EventArgs e)
{
Calendar1.Visible = true;
}
protected void Calendar1_SelectionChanged(object sender, EventArgs e)
{
tbdates.Text = Calendar1.SelectedDate.ToShortDateString();
Calendar1.Visible = false;
}
protected void Button1_Click(object sender, EventArgs e)
{
//DateTime date = Convert.ToDateTime(tbdates.Text);
SqlConnection sqlcon = new SqlConnection(ConfigurationManager.ConnectionStrings["MyDatabase1ConnectionString"].ToString());
sqlcon.Open();
string query = "select * from Ticket where date = #Date";
SqlCommand cmd = new SqlCommand(query, sqlcon);
SqlParameter date = cmd.Parameters.Add("#Date", SqlDbType.DateTime);
SqlDataReader rdr = cmd.ExecuteReader();
GridView1.DataSource = rdr;
GridView1.DataBind();
sqlcon.Close();
}
}
}

there are a few mistakes in your code, i recommend you to read about CRUD Operations using ADO.Net and C# in ASP.Net, how to use SqlConnection and SqlCommand types. When you work with asp.net web forms you can use SqlDataSource control to provide data for your controls.
<form id="form1" runat="server">
<div>
<asp:TextBox ID="tbdates" runat="server"></asp:TextBox>
<asp:Button ID="Button2" runat="server" OnClick="Button2_Click" Text="Button" />
<asp:DropDownList ID="DropDownList1" runat="server" DataSourceID="SqlDataSource1" DataTextField="Bickup" DataValueField="Bickup">
</asp:DropDownList>
<asp:DropDownList ID="DropDownList2" runat="server" DataSourceID="SqlDataSource1" DataTextField="DropOff" DataValueField="Dropoff">
</asp:DropDownList>
</div>
<asp:Calendar ID="Calendar1" runat="server" OnSelectionChanged="Calendar1_SelectionChanged"></asp:Calendar>
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"
CssClass="table table-hover table-striped" DataSourceID="SqlDataSource2">
<Columns>
<asp:BoundField DataField="BusNo" HeaderText="Bus Number" />
<asp:BoundField DataField="date" HeaderText="Date" />
<asp:BoundField DataField="Time" HeaderText="Time" />
<asp:BoundField DataField="Bickup" HeaderText="Bick Up" />
<asp:BoundField DataField="DropOff" HeaderText="Drop Off" />
<asp:BoundField DataField="Fare" HeaderText="Fare" />
</Columns>
<HeaderStyle BackColor="#33CCFF" />
</asp:GridView>
<asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click" />
<br />
<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:MyDatabase1ConnectionString %>"
SelectCommand="SELECT [BusNo], [date], [time], [Bickup], [DropOff], [Fare] FROM [Ticket]">
</asp:SqlDataSource>
<asp:SqlDataSource ID="SqlDataSource2" runat="server" ConnectionString="<%$ ConnectionStrings:MyDatabase1ConnectionString %>" SelectCommand="SELECT [BusNo], [date], [time], [Bickup], [DropOff], [Fare] FROM [Ticket] WHERE ([date] = #date)">
<SelectParameters>
<asp:CookieParameter CookieName="date" DbType="Date" Name="date" />
</SelectParameters>
</asp:SqlDataSource>
this is yours DriverDisplay :
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
DropDownList1.DataBind();
DropDownList2.DataBind();
}
}
protected void Button2_Click(object sender, EventArgs e)
{
Calendar1.Visible = true;
}
protected void Calendar1_SelectionChanged(object sender, EventArgs e)
{
tbdates.Text = Calendar1.SelectedDate.ToShortDateString();
Calendar1.Visible = false;
}
protected void Button1_Click(object sender, EventArgs e)
{
if (Request.Cookies["date"] == null)
{
Request.Cookies.Add(new HttpCookie("date"));
}
Request.Cookies["date"].Value = tbdates.Text;
}

Javascript confirmation Box not appear on delete in gridview

When click on delete link-button in gridview, Confirmation Box not appeared. I write this code but I don't know why it's not working...
<asp:GridView ID="gvwAuctionExport" runat="server" AutoGenerateColumns="false" OnRowCommand="gvwAuctionExport_RowCommand" OnRowDataBound="gvwAuctionExport_RowDataBound" OnRowDeleting="gvwAuctionExport_RowDeleting">
<Columns>
<asp:TemplateField>
<ItemTemplate>
<div class="btn-group btn-group-xs" id="bgroup">
<asp:LinkButton ID="lnkInspectionDelete" runat="server" Text="Delete" CssClass="btn btn-danger" CommandArgument='<%# Eval("inspection_id") %>' CommandName="Delete"></asp:LinkButton>
</div>
</ItemTemplate>
</asp:TemplateField>
<asp:BoundField DataField="address" HeaderText="Address" />
<asp:BoundField DataField="city" HeaderText="City" />
<asp:BoundField DataField="state" HeaderText="State" />
</Columns>
</asp:GridView>
protected void gvwAuctionExport_RowCommand(object sender, GridViewCommandEventArgs e)
{
if (e.CommandName == "Delete")
{
int InspectionID = Convert.ToInt32(e.CommandArgument);
string status = string.Empty;
status = DACls.DeleteInspectionByID(InspectionID);
}
}
protected void gvwAuctionExport_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
LinkButton l = (LinkButton)e.Row.FindControl("lnkInspectionDelete");
l.Attributes.Add("onclick", "javascript:return " +
"confirm('Are you sure you want to delete this record");
}
}
protected void gvwAuctionExport_RowDeleting(object sender, GridViewDeleteEventArgs e)
{
bindGridView();
}
public void bindGridView(){
DataSet DS = new DataSet();
SqlConnection DBCon = new SqlConnection(ConfigurationManager.ConnectionStrings["ConStr"].ConnectionString);
SqlCommand Cmd = new SqlCommand("USP_Inspection_Export", DBCon);
Cmd.CommandType = CommandType.StoredProcedure;
SqlDataAdapter AHadp = new SqlDataAdapter(Cmd);
AHadp.Fill(this.DS);
DataTable dt = DS.Tables[0];
this.gvwAuctionExport.DataSource = dt;
this.gvwAuctionExport.DataBind();
}
When I click on delete button and check from debugger it is not going to GridView RowDataBound function scope. I don't know what happening here?

CheckBox is not working when I am pressing the button

I am working with Asp.Net C# and want to take the id of the row with a checkbox from the GridView.
With the code above if is checked the only think i am getting with debug is:
chk: {Text = "" Checked = false}
What i am doing wrong and how i can fix this?
<!-- language: lang-css -->
protected void Page_Load(object sender, EventArgs e)
{
string query = "SELECT * FROM routedoc WHERE Recipient=#user ";
string user = Session["user"].ToString();
MySqlConnection con = new MySqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["imagingConnectionString"].ConnectionString);
MySqlCommand cmd = new MySqlCommand(query, con);
cmd.Parameters.AddWithValue("#user", user);
con.Open();
DataTable dataTable = new DataTable();
MySqlDataAdapter da = new MySqlDataAdapter(cmd);
da.Fill(dataTable);
GridView1.DataSource = dataTable;
GridView1.DataBind();
if(!IsPostBack)
{
BindDropDown();
}
}
private void BindDropDown()
{
string user = Session["user"].ToString();
using (MySqlConnection con2 = new MySqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["imagingConnectionString"].ConnectionString))
{
MySqlDataAdapter adp = new MySqlDataAdapter("SELECT RouteNo,sender FROM routedoc WHERE Recipient = #user ", con2);
adp.SelectCommand.Parameters.AddWithValue("?user", user);
DataTable dt = new DataTable();
adp.Fill(dt);
if (dt.Rows.Count > 0)
{
DropDownList1.DataSource = dt;
DropDownList1.DataTextField = "sender";
DropDownList1.DataValueField = "RouteNo";
DropDownList1.DataBind();
}
}
}
protected void Button1_Click(object sender, EventArgs e)
{
// Response.Write(GridView1.SelectedRow.Cells[1].Text);
foreach(GridViewRow row in GridView1.Rows)
{
var chk = row.FindControl("box") as CheckBox ;
if (chk.Checked)
{
var id = row.FindControl("RouteNo") as Label;
Response.Write(id.Text);
}
}
}
routedoc.aspx:
<%# Page Language="C#" AutoEventWireup="true" CodeBehind="routedoc.aspx.cs" Inherits="WebApplication2.WebForm2" %>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<h1>page 2<asp:DropDownList ID="DropDownList1" runat="server" Height="20px" AutoPostBack="True" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged" Width="136px" >
</asp:DropDownList>
</h1>
</div>
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="Recipient,DocHandle,Sender" OnSelectedIndexChanged="GridView1_SelectedIndexChanged" >
<Columns>
<asp:BoundField DataField="RouteNo" HeaderText="RouteNo" InsertVisible="False" SortExpression="RouteNo" />
<asp:BoundField DataField="Recipient" HeaderText="Recipient" ReadOnly="True" SortExpression="Recipient" />
<asp:BoundField DataField="DocHandle" HeaderText="DocHandle" ReadOnly="True" SortExpression="DocHandle" />
<asp:BoundField DataField="Sender" HeaderText="Sender" ReadOnly="True" SortExpression="Sender" />
<asp:BoundField DataField="TermNo" HeaderText="TermNo" SortExpression="TermNo" />
<asp:BoundField DataField="SentDate" HeaderText="SentDate" SortExpression="SentDate" />
<asp:BoundField DataField="DueDate" HeaderText="DueDate" SortExpression="DueDate" />
<asp:BoundField DataField="SentTime" HeaderText="SentTime" SortExpression="SentTime" />
<asp:BoundField DataField="DueTime" HeaderText="DueTime" SortExpression="DueTime" />
<asp:BoundField DataField="Action" HeaderText="Action" SortExpression="Action" />
<asp:BoundField DataField="Notes" HeaderText="Notes" SortExpression="Notes" />
<asp:BoundField DataField="BUDate" HeaderText="BUDate" SortExpression="BUDate" />
<asp:TemplateField HeaderText="Select">
<ItemTemplate><asp:CheckBox ID="Box" runat="server"/>
</ItemTemplate></asp:TemplateField>
</Columns>
</asp:GridView>
<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:imagingConnectionString %>" ProviderName="<%$ ConnectionStrings:imagingConnectionString.ProviderName %>" SelectCommand="SELECT * FROM routedoc "></asp:SqlDataSource>
<asp:Button ID="Button1" runat="server" Height="43px" OnClick="Button1_Click" Text="DELETE" Width="109px" />
</form>
</body>
</html>

This is caused by the fact that you always bind your GridView1 with data,
even on post-back. This is causing that all check box-es remain unchecked.
Remove grid loading if you are in post-back, and it should work fine.
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
string query = "SELECT * FROM routedoc WHERE Recipient=#user ";
string user = Session["user"].ToString();
MySqlConnection con = new MySqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["imagingConnectionString"].ConnectionString);
MySqlCommand cmd = new MySqlCommand(query, con);
cmd.Parameters.AddWithValue("#user", user);
con.Open();
DataTable dataTable = new DataTable();
MySqlDataAdapter da = new MySqlDataAdapter(cmd);
da.Fill(dataTable);
GridView1.DataSource = dataTable;
GridView1.DataBind();
BindDropDown();
}
}
If you, however, need to load grid even in post-back, I will tell you a fix for that.

Whenever you bind a data to a data control in Page_Load event, please consider using Page.IsPostBack
protected void Page_Load(object sender, EventArgs e)
{
if(!Page.IsPostBack)
{
// bind data
}
}
This is because, when you click a button, your page will be still refreshed, which means you will bind the same data to gridview again, resulting in unchecked checkboxes. You can check whether the page is loaded by a button click (Page.IsPostBack) or the page is loaded the first time (!Page.IsPostBack), and do your data binding accordingly.
Hope this makes sense!

Storing BoundField Value in HiddenField on Button Click

I'm having trouble with setting a HiddenField's value to a GridView item value. What I want to do is get the value of a BoundField (in this case, "FIPSCountyCode") in a GridView and store it in a HiddenField when the user clicks a button (in this case, "btnEdit") to make changes to a entry in the grid. I haven't used HiddenFields before, so I have forgotten what to do here.
The HiddenField is setup like this:
<asp:HiddenField ID="hdnFIPS" Value='<%#Eval("FIPSCountyCode")%>' runat="server" />
This is what the GridView is setup like:
<asp:GridView ID="CountyList" runat="server" AutoGenerateColumns="False" Width="90%" SkinId="PagedList" PagerSettings-Position="TopAndBottom" PagerStyle-Wrap="True">
<Columns>
<asp:BoundField HeaderText="County Code" DataField="FIPSCountyCode" />
<asp:BoundField HeaderText="State Code" DataField="StateCode" />
<asp:BoundField HeaderText="County Name" DataField="CountyName" />
<asp:BoundField HeaderText="Tax Rate" DataField="TaxRate" />
<asp:TemplateField>
<ItemTemplate>
<asp:ImageButton ID="btnEdit" runat="server" SkinID="EditIcon" OnClick="EditInfo" CommandName="DoEdit" />
<asp:ImageButton ID="DeleteButton" runat="server" SkinID="DeleteIcon" CommandName="DoDelete"
OnClientClick="return confirm('Are you sure you want to remove this item and all of its options?')"
CausesValidation="false" />
</ItemTemplate>
</asp:TemplateField>
</Columns>
<AlternatingRowStyle CssClass="even" />
</asp:GridView>
And this is the code behind:
public partial class Admin_County_Info : CommerceBuilder.UI.AbleCommerceAdminPage
{
private string redirectString = String.Empty;
protected void Page_Load(object sender, System.EventArgs e)
{
if (!Page.IsPostBack)
PopulateCountyGrid();
}
protected void PopulateCountyGrid()
{
try
{
System.Data.SqlClient.SqlDataReader dr = null;
using (SqlConnection cn = new SqlConnection(ConfigurationManager.ConnectionStrings["AbleCommerce"].ToString()))
{
SqlCommand cmd = new SqlCommand("SELECT [FIPSCountyCode], [StateCode], [CountyName], [TaxRate] FROM [baird_InfoCounty]", cn);
cmd.CommandType = CommandType.Text;
cn.Open();
dr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
CountyList.DataSource = dr;
CountyList.DataBind();
}
}
catch (Exception eX)
{
}
}
#region Clicks and Event Handlers
protected void EditInfo(object sender, System.EventArgs e)
{
if (Page.IsValid)
{
redirectString = "~/Admin/Taxes/AddEditCountyInfo.aspx?FIPSCountyCode=" + hdnFIPS.Value;
Response.Redirect(redirectString);
}
}
protected void AddInfo(object sender, System.EventArgs e)
{
if (Page.IsValid)
{
Response.Redirect("~/Admin/Taxes/AddEditCountyInfo.aspx");
}
}
}
This must be a really dumb question but I'm really not sure how to proceed. Any help would be great!

You can get the value of FIPSCountyCode from the BoundField this way:
protected void EditInfo(object sender, System.EventArgs e)
{
if (Page.IsValid)
{
GridViewRow gvr = ((ImageButton)sender).NamingContainer as GridViewRow;
hdnFIPS.Value = gvr.Cells[0].Text;
redirectString = "~/Admin/Taxes/AddEditCountyInfo.aspx?FIPSCountyCode=" + hdnFIPS.Value;
Response.Redirect(redirectString);
}
}