Develop Reference

change Panel Visibilty on SqlDataReader value and trim first two characters from Eval string C#

Currently i have two problems.
Problem 1. Im trying to change the Visibility of two Panels based on what value the reader gets from reader["Maskine_Type"].ToString() as you can see in the Codebehind below. Because the Panels are inside a repeater i also use the:
Panel PanelTilbud = (Panel)Page.FindControl("PanelTilbud"); again you can see below. however, when i run the code it gives me a Object reference not set to an instance of an object on PanelTilbud.Visible = true; i assume because it still cant find the Panels. i tested with panels outside of the repeater and it works fine.
I also tried to make the Repeater OnItemDataBound="Repeater1_ItemDataBound"
and changed to Panel PanelTilbud = (Panel)e.Item.FindControl("PanelTilbud");
However then i get the error Insufficient stack to continue executing the program safely
Problem 2.
Inside one of the panels, i run this code
<%# (Eval("Maskine_Tilbud").ToString().Substring(Eval("Maskine_Tilbud").ToString().Length - 2))%>
in order to remove the first two characters in the string from Eval("Maskine_Tilbud") which works fine, however most records in the database will have a null inMaskine_Tilbud and if its null i get the error StartIndex cannot be less than zero which makes sense, but i dont know how else to remove the first two characters from Eval("Maskine_Tilbud")
.aspx markup
<asp:Repeater ID="Repeater1" runat="server">
<ItemTemplate>
<asp:Panel ID="PanelTilbud" runat="server" Visible="false">
<hr />
<h4 class="radfont text-center">Tilbud! -<%# (Eval("Maskine_Tilbud").ToString().Substring(Eval("Maskine_Tilbud").ToString().Length - 2))%>% pr dag!</h4>
</asp:Panel>
<asp:Panel ID="PanelNormal" runat="server">
<hr />
<h4 class="text-center orangeFont"><%#Eval("Maskine_pris") %><span class="hvidfont">,- pr dag inkl moms</span>
<span class="orangeFont">(<%#Eval("Maskine_Upris") %>,- ekskl)</span>
</h4>
<hr />
</asp:Panel>
</ItemTemplate>
</asp:Repeater>
My Codebehind - in Page_Load
SqlConnection conn = new SqlConnection();
conn.ConnectionString = ConfigurationManager.ConnectionStrings["DatabaseConnectionString1"].ToString();
SqlCommand cmd = new SqlCommand();
cmd.Connection = conn;
cmd.CommandText = "SELECT top 1 * FROM [Maskiner] INNER JOIN Maskine_kategori ON Maskiner.Maskine_Kategorinavn = Maskine_kategori.Maskine_kategori_id WHERE ([Maskine_id] = #Maskine_id)";
cmd.Parameters.Add("#Maskine_id", SqlDbType.Int).Value = Request.QueryString["Maskine_id"];
conn.Open();
SqlDataReader reader = cmd.ExecuteReader();
Panel PanelTilbud = (Panel)Page.FindControl("PanelTilbud");
Panel PanelNormal = (Panel)Page.FindControl("PanelNormal");
if (reader.Read())
{
if (reader["Maskine_Type"].ToString() == "Tilbud")
{
PanelTilbud.Visible = true;
PanelNormal.Visible = false;
}
if (reader["Maskine_Type"].ToString() == "Normal")
{
PanelTilbud.Visible = false;
PanelNormal.Visible = true;
}
}
conn.Close();
DataTable select_favorit_db = new DataTable();
SqlDataAdapter dt = new SqlDataAdapter(cmd);
dt.Fill(select_favorit_db);
Repeater1.DataSource = select_favorit_db;
Repeater1.DataBind();
I hope you can understand my questions.

Late to the party here. Just thought I should add that you can have methods in your page and use them in your data binding expressions. Sample:
ASPX:
<form id="form1" runat="server">
<asp:Repeater ID="rep" runat="server">
<ItemTemplate>
<asp:Label ID="lab" runat="server"
Text='<%# Trim2Chars(Eval("test")) %>'></asp:Label>
</ItemTemplate>
</asp:Repeater>
</form>
Code behind:
protected void Page_Load(object sender, EventArgs e)
{
//create fake data for demo and bind to repeater
var data = Enumerable.Range(0, 10).Select(i => new { test = "foo " + i });
rep.DataSource = data;
rep.DataBind();
}
public string Trim2Chars(object input)
{
string inputString = input as string;
if (inputString == null)
return "";
if (inputString.Length < 2)
return inputString;
return inputString.Substring(2);
}
This way, you can keep the ASPX file a bit cleaner and have more complex data binding expressions evaluated in the code behind.

You can set the Visibility in the Control itself
<asp:Panel ID="PanelTilbud" runat="server" Visible='<%# Eval("Maskine_Type").ToString() == "myValue" %>'>
</asp:Panel>
Or in the ItemDataBound event code behind
protected void Repeater1_ItemDataBound(object sender, RepeaterItemEventArgs e)
{
//use findcontrol to find the panel and cast it as one
Panel panel = e.Item.FindControl("PanelTilbud") as Panel;
//get the current datarowview
DataRowView row = e.Item.DataItem as DataRowView;
//check the value and change the panel visibility
if (row["Maskine_Type"].ToString() == "myValue")
{
panel.Visible = true;
}
}
To check for NULL values you have to use a ternary operator.
<%# !string.IsNullOrEmpty(Eval("Maskine_Type").ToString()) ? Eval("Maskine_Type").ToString().Substring(0, Eval("Maskine_Type").ToString().Length - 2) : "Field is empty" %>

How do I show an associated value with a dropdown list item (after choosing it from the list)?

I am programming in ASP.NET, visual studio. I have a dropdown list created in HTML form. If I dropdown the list, it displays the record from associated column in the table. But what I want is to show the corresponding value / record with that list item.
For example in the table, I have column id, productname and price. After choosing a particular product name (from drop down list), the associated price with it must be displayed in front of it (in a label).
However, By default, I want the drop down list to shows nothing in the beginning.
UPDATE:
Store.aspx:
<form id="form1" runat="server">
<div>
Welcome
<asp:Label ID="Label3" runat="server" ></asp:Label>
<br />
<br />
Products: <asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="true" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged" ></asp:DropDownList>
<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:ConnectionString %>" SelectCommand="SELECT * FROM [productdata]"></asp:SqlDataSource>
Price:
<asp:Label ID="Label1" runat="server" ></asp:Label>
<br />
<br />
<asp:Button ID="Button1" runat="server" Text="Add to Cart" />
<br />
<br />
Items in cart: <asp:DropDownList ID="DropDownList2" runat="server"></asp:DropDownList>
<br />
<br />
Total Price: <asp:Label ID="Label2" runat="server"></asp:Label>
</div>
</form>
Store.aspx.cs:
public partial class Store : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
Label3.Text = Request.QueryString["name"];//show welcome text
String cs = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
if (!IsPostBack)
{
using (SqlConnection sc = new SqlConnection(cs))
{
SqlCommand sqlcom = new SqlCommand("Select id, productname, price from productdata", sc);
sc.Open();
DropDownList1.DataTextField = "productname";//show in the dropdown list
DropDownList1.DataValueField = "price"; //show in the label
DropDownList1.DataSource = sqlcom.ExecuteReader();
DropDownList1.DataBind();
}
}
}
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
String cs = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
SqlDataReader rd;
using (SqlConnection sc = new SqlConnection(cs))
{
SqlCommand sqlcom = new SqlCommand("Select id, productname, price from productdata where id=" + Convert.ToUInt32(DropDownList1.SelectedValue), sc);
sc.Open();
rd = sqlcom.ExecuteReader();
if (rd.Read())
{
Label1.Text = rd[2].ToString();
}
sc.Close();
}
}
}
Database:
CREATE TABLE [dbo].[productdata] (
[Id] INT NOT NULL,
[productname] VARCHAR (50) NULL,
[price] FLOAT (53) NULL,
PRIMARY KEY CLUSTERED ([Id] ASC)
);

This Edit according to using AutoPostBack=True and if (!IsPostBack) in Page_Load thanks to Arindam:
For simply solution using postback event:
First you should add OnSelectedIndexChanged event for dropdownlist
<asp:DropDownList ID="DropDownList1" runat="server"
OnSelectedIndexChanged="GetPrice" AutoPostBack="true">
</asp:DropDownList>
Then in code behind you just get selected value and fill to the label price
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
Label3.Text = Request.QueryString["name"];//show welcome text
String cs = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
using (SqlConnection sc = new SqlConnection(cs))
{
SqlCommand sqlcom = new SqlCommand("Select id, productname, price from productdata", sc);
sc.Open();
DropDownList1.DataTextField = "productname";//show in the dropdown list
DropDownList1.DataValueField = "price"; //show in the label
DropDownList1.DataSource = sqlcom.ExecuteReader();
DropDownList1.DataBind();
}
}
}
protected void GetPrice(object sender, EventArgs e)
{
Label1.Text = DropDownList1.SelectedValue;
}
You have to use AutoPostBack=True so that when you change index of dropdownlist, it will trigger a postback to server so the function GetPrice(...) will be called.
Every time the page postback, it will call function Page_Load(...) first, so you must use propertive IsPostBack to check if case1_this is the first time the page is loaded, or case2_a postback event, and you only set the ddl datasource at case1 because if you set datasource, by default the dropdownlist will reset to select first item in list.
When you go advance, you should consider using Javascript and Jquery to solve this, so the page will not load again like this postback solution.
And one more thing, you should name your controls well, don't make them default like that. It's one of two hard things in programming.

Yes you can but if not please use datatable and i am sure that work fine .if u not able do that just post I will give the correction.

asp.net RequiredFieldValidator

I have a problem.
I have a registration and some RequiredFieldValidator controlls.
Problem:
If i leave the textbox empty, then i can see the errormessage. But it write the values in my database. i want that it stops, and not writing the values in my DB.
Thank you very much!
Kevin
Aspx
<tr>
<td id="LabelBenutzername" class="auto-style2">Benutzername</td>
<td>
<asp:TextBox ID="TextBoxRBenutzername" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="RequiredFieldValidator1"
runat="server" ControlToValidate="TextBoxRBenutzername"
ErrorMessage="Bitte einen Benutzernamen eingeben" ForeColor="Red">
</asp:RequiredFieldValidator>
</td>
</tr>
Codebehind
if (IsPostBack)
{
SqlCommand cmd = new SqlCommand("select * from tabUser where Benutzername = #Benutzername", con);
SqlParameter param = new SqlParameter();
param.ParameterName = "#Benutzername";
param.Value = TextBoxRBenutzername.Text;
cmd.Parameters.Add(param);
con.Open();
SqlDataReader reader = cmd.ExecuteReader();
if (reader.HasRows)
{
Label1.Text = "User Id already exists";
con.Close();
return;
}
con.Close();
}
try
{
SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["DBFitnessBlogConnectionString"].ToString());
SqlCommand cmd = new SqlCommand();
cmd.Connection = con; //assigning connection to command
cmd.CommandType = CommandType.Text; //representing type of command
//cmd.CommandText = "INSERT INTO UserDetails (Fname,Lname,Email,Password,Gender,Dob,Mobile,Address) values
// (#Fname,#Lname,#Email,#Password,#Gender,#Dob,#Mobile,#Address)";
cmd.CommandText = "INSERT INTO tabUser values(#Benutzername,#Passwort,#Vorname,#Nachname,#Email)";
//adding parameters with value
cmd.Parameters.AddWithValue("#Benutzername", TextBoxRBenutzername.Text.ToString());
cmd.Parameters.AddWithValue("#Passwort", TextBoxRPasswort.Text.ToString());
cmd.Parameters.AddWithValue("#Vorname", TextBoxRVorname.Text.ToString());
cmd.Parameters.AddWithValue("#Nachname", TextBoxRNachname.Text.ToString());
cmd.Parameters.AddWithValue("#Email", TextBoxREmail.Text.ToString());
con.Open(); //opening connection
cmd.ExecuteNonQuery(); //executing query
con.Close(); //closing connection
Label1.Text = "Registration erfolgreich..";
}
catch (Exception ex)
{
Label1.Text = "Registration erfolgreich NICHT..";
}
}

In your code-behind, wrap the database logic in a check to see if the page is valid or not, like this:
if(Page.IsValid)
{
// Do database logic here
}

Quick answer: In your code-behind file, write into the event to check for validation prior to proceeding with the database update.
protected void btnUpdateSettings_Click(object sender, EventArgs e)
{
if (IsValid)
{
// Event Programming Code Goes Here
}
}
The idea would be that if any controls had triggered validation controls, then the form could post-back, but then there would be no code execution.

Before you make your call to the database to update your data, check
Page.IsValid == true
before you make your update.
This should be false if your validation failed.

I don't see your submit button. But I have used your code to show you how I do mine. It looks like you are missing the ValidationGroup in both controls.
<tr>
<td id="LabelBenutzername" class="auto-style2">Benutzername</td>
<td>
<asp:TextBox ID="TextBoxRBenutzername" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ControlToValidate="TextBoxRBenutzername" ValidationGroup="Insert" ErrorMessage="Bitte einen Benutzernamen eingeben" ForeColor="Red"></asp:RequiredFieldValidator>
<asp:Button ID="btnSubmit" runat="server" Text="Submit" Font-Size="Smaller" Height="29px" OnClick="btnSubmit_Click" Width="59px" ValidationGroup="Insert" CausesValidation="true" />
</td>
</tr>
I hope this helps.
Note that you can also use a validation summary.

Gridview paging in ModalPopupExtender strange behaviour

I have a modalpopypextender that contains a grid view and I want populate it on button click which does this:
protected void btnViewRecipients_Click(object sender, EventArgs e)
{
ModalPopupExtender1.Show();
BindData();
}
Which is straight forward. BindData does this:
protected void BindData()
{
try
{
SqlCommand sqlCommand = new SqlCommand();
string connectionString = "Data Source=SERVER\\DB1;Initial Catalog=Survey;User ID=abcde;Password=12345;";
using (SqlConnection sqlConnection = new SqlConnection(connectionString))
{
sqlCommand = sqlConnection.CreateCommand();
sqlCommand.CommandText = "Select * From [Survey].[dbo].[data]";
SqlDataAdapter sda = new SqlDataAdapter(sqlCommand.CommandText, connectionString);
SqlCommandBuilder scb = new SqlCommandBuilder(sda);
//Create a DataTable to hold the query results.
//Fill the DataTable.
sda.Fill(dTable);
//Set the DataGridView DataSource.
gvRecords.DataSource = dTable;
gvRecords.DataBind();
sqlConnection.Close();
}
}
catch (SqlException ex)
{
//Console.WriteLine(ex.StackTrace);
}
}
Now this all works good and I get to see the grid with data. I then turned on autopaging and went ahead to create the call gvRecords_PageIndexChanged. I have also turned on EnableSortingAndPagingCallbacks.
protected void gvRecords_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
gvRecords.PageIndex = e.NewPageIndex;
gvRecords.DataSource = dTable;
gvRecords.DataBind();
}
This kinda works very strangely. I noticed that when I click a page number, the table becomes blank and shows me EmptyDataText that I defined earlier. But when I close the ModalPopupExtender and open it again (clicking the button again) it shows me the right page and data! e.g. if I clicked page 3, then get a blank table, now reopening the MPE will show me page 3's contents in a gridview. I guess that's the viewstate stored somewhere but why is it that the gridview will not show me the page right away?
I am really stuck at this and failing to understand what I'm missing!
Any help appreciated million times, I have searched and searched online for this but maybe it is so trivial and obvious that no one has ever needed to ask!?!

Edited I've been working with Modals, UpdatePanels and ListViews for years, we'll solve this, but it would be good to see the entire markup.
From your comments I'd suggest;
Put your entire modal markup in the UpdatePanel. Make sure to set the ID and UpdateMode to conditional;
<asp:UpdatePanel ID="upModal" runat="server" UpdateMode="Conditional">
<ContentTemplate>
</ContentTemplate>
</asp:UpdatePanel>
I usually use an ASP:Panel as my DIV inside my update panel;
<asp:Panel ID="pnlPopup" runat="server" CssClass="ModalPanel">
Then place your GridView (or in my case ListView) in your panel
In your code behind after you call your gvRecords.Databind(), call upModal.Update()
protected void gvRecords_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
gvRecords.PageIndex = e.NewPageIndex;
gvRecords.DataSource = dTable;
gvRecords.DataBind();
upModal.Update();
}

I got it working finally, I have had to set PopupControlID to upModal, the updatepanel's ID, as opposed to the inner panel. The targetcontrolID also had to point to a hidden button, as many have found you must when working with MPEs...
Anyway, here goes:
<asp:Button ID="hiddenButton" runat="server" Text="" style="display:none;" />
<ajaxToolkit:ModalPopupExtender ID="ModalPopupExtender1" runat="server" Enabled="True" TargetControlID="hiddenButton" PopupControlID="upModal" BehaviorID="modalbehavior" BackgroundCssClass="modalBackground" OnCancelScript="cancelClick();" CancelControlID="closePopup">
</ajaxToolkit:ModalPopupExtender>
<asp:UpdatePanel runat="server" ID="upModal" UpdateMode="Conditional">
<ContentTemplate>
<asp:Panel id="pnlPopup" runat="server" class="ModalPanel" >
<table cellpadding="5" cellspacing="5" class="topBanner" style="width:100%;">
<tr>
<td width="50">
<asp:LinkButton ID="closePopup" runat="server" onclick="LinkButton1_Click" CssClass="ClosePopupCls">Close
[x]</asp:LinkButton>
</td>
<td align="center">
<asp:Label ID="lbl" runat="server" Text="Status"></asp:Label>
</td>
<td width="25">
</td>
</tr>
<tr>
<td colspan="3">
<asp:GridView ID="gvRecords" runat="server" AllowPaging="True"
BackColor="White" EmptyDataText="No Record Found"
EnableSortingAndPagingCallbacks="True" ForeColor="GrayText" Height="600"
onpageindexchanging="gvRecords_PageIndexChanging" Width="800">
</asp:GridView>
</td>
</tr>
</table>
</asp:Panel>
</ContentTemplate>
</asp:UpdatePanel>

Buttons and repeater control

I am using ASP.NET, C#, Sql Server 2005 for my project and
I'm using the repeater control to form a table of users that are a member of a site and a button next to each user so that they can be added to your friends list. I have everything set up except I dont know how to get the specific info of each row after a button click. I mean,
How to send a friend request to a person whose username is displayed besides the button? or
How to access the the displayed username besides the button so that I can use it for my code?
My Script
<asp:Repeater ID="myrepeater" runat="server">
<HeaderTemplate>
<table style="font: 8pt verdana">
<tr style="background-color:#3C78C3">
<th>Search Result</th>
</tr>
</HeaderTemplate>
<ItemTemplate>
<tr>
<td>
<%#DataBinder.Eval(Container,"DataItem.allun")%>
<asp:Button ID="Button1" runat="server" Text="Button" />
</td>
</tr>
</ItemTemplate>
<FooterTemplate>
</table>
</FooterTemplate>
Code Behind
protected void btnSearch_Click(object sender, EventArgs e)
{
con.Open();
if (txtSearch.Text != "")
{
SqlDataAdapter mycommand = new SqlDataAdapter("select * from WebAdminTable where allun='" + txtSearch.Text + "'", con);
DataSet ds = new DataSet();
mycommand.Fill(ds);
myrepeater.DataSource = ds;
myrepeater.DataBind();
}
else
{
//msgbox for entering value
}
con.Close();
}
protected void btnAddToMyFList_Click(object sender, EventArgs e)
{
//?
}

You can bind the userName to a label control and then you can access the value of the label control on the click of button like...
protected void btnAddToMyFList_Click(object sender, EventArgs e)
{
Button btnAddToMyFList = (Button)sender;
Label label = (Label)btnAddToMyFList.Parent.FindControl("LabelId");
String labelText = label.Text; //userName of clicked row
}