I have followed the tutorial at codeproject, and have stumbled into an issue.
I have a ListView, listing all the current members names of my site:
<asp:ListView ID="lstMembers" runat="server">
<LayoutTemplate>
<table>
<tr>
<th>Name</th>
</tr>
<tr id="itemPlaceholder" runat="server"></tr>
</table>
</LayoutTemplate>
<ItemTemplate>
<tr>
<td>
<%# Eval("MemberName") %>
</td>
</tr>
</ItemTemplate>
</asp:ListView>
And a DataPager underneath:
<asp:DataPager ID="DataPagerProducts" runat="server" PagedControlID="lstMembers"
PageSize="3" OnPreRender="DataPagerProducts_PreRender">
<Fields>
<asp:NumericPagerField />
</Fields>
</asp:DataPager>
I am using the following to bind to the List (As per the tutorial):
List<Members> member = new List<Members>();
protected void Page_Load(object sender, EventArgs e)
{
if(Page.IsPostBack) return;
DisplayMembers();
}
private void DisplayMembers()
{
const string strSql = "SELECT DISTINCT [id], [memberNickname] FROM vwGetMemberDetails ORDER BY [memberNickname]";
SqlCommand sqlComm = new SqlCommand(strSql, DataConn.Connect()) { CommandType = CommandType.Text };
SqlDataReader rdr = sqlComm.ExecuteReader();
while (rdr.Read())
{
member.Add(new Members
{
MemberId = rdr["id"],
MemberName = rdr["memberNickname"]
});
}
rdr.Close();
DataConn.Disconnect();
}
private class Members
{
public object MemberId { get; set; }
public object MemberName { get; set; }
}
protected void DataPagerProducts_PreRender(object sender, EventArgs e)
{
lstMembers.DataSource = member;
lstMembers.DataBind();
}
So there are currently 2 numbers on the Pager. But, every time I click 2, the List displays nothing, and the Pager disappears.
I am usually a frequent worker of the Repeater control, and am only using this method as an assumingly 'easier' way.
Can anyone tell me where I'm going wrong?
Your variable model is not updating in the DataPagerProducts_PreRender so it will always display the same dataset already loaded in the page load.
EDIT
removing if(Page.IsPostBack) return; or calling DisplayMembers() inside the DataPagerProducts_PreRender will work this for me
Related
Please consider this scenario:
I have a simple page and I want to log all controls causing postback. I create this simple page. It contains a grid to show some URLs and when user click on an icon a new tab should open:
<form id="form1" runat="server">
<div>
<table style="width: 100%;">
<tr>
<td style="background-color: #b7ffbb; text-align: center;" colspan="2">
<asp:Button ID="Button3" runat="server" Text="Click Me First" Height="55px" OnClick="Button3_Click" />
</td>
</tr>
<tr>
<td style="background-color: #f1d8fe; text-align: center;" colspan="2">
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false" BackColor="White" OnRowCommand="GridView1_RowCommand">
<Columns>
<asp:BoundField DataField="SiteAddress" HeaderText="Address" />
<asp:TemplateField>
<ItemTemplate>
<asp:ImageButton ID="ImageButton1" ImageUrl="~/download.png" runat="server" CommandArgument='<%# Eval("SiteAddress") %>' CommandName="GoTo" Height="32px" Width="32px" />
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
</td>
</tr>
</table>
</div>
</form>
and code behind:
public partial class WebForm2 : Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void Button3_Click(object sender, EventArgs e)
{
List<Address> Addresses = new List<Address>()
{
new Address(){ SiteAddress = "https://google.com" },
new Address(){ SiteAddress = "https://yahoo.com" },
new Address(){ SiteAddress = "https://stackoverflow.com" },
new Address(){ SiteAddress = "https://learn.microsoft.com/}" }
};
GridView1.DataSource = Addresses;
GridView1.DataBind();
}
protected void GridView1_RowCommand(object sender, GridViewCommandEventArgs e)
{
ScriptManager.RegisterStartupScript(this, this.GetType(), "MyScript", "window.open('" + e.CommandArgument.ToString() + "', '_blank')", true);
}
}
class Address
{
public string SiteAddress { get; set; }
}
every thing is fine till here. Now I create a base class for all of my pages and add below codes for finding postback control:
public class MyPageBaseClass : Page
{
protected override void OnInit(EventArgs e)
{
if (!IsPostBack)
{
}
else
{
var ControlId = GetPostBackControlName(); <------
//Log ControlId
}
base.OnInit(e);
}
private string GetPostBackControlName()
{
Control control = null;
string ctrlname = Page.Request.Params["__EVENTTARGET"];
if (ctrlname != null && ctrlname != String.Empty)
{
control = Page.FindControl(ctrlname);
}
else
{
foreach (string ctl in Page.Request.Form)
{
Control c;
if (ctl.EndsWith(".x") || ctl.EndsWith(".y"))
{
string ctrlStr = ctl.Substring(0, ctl.Length - 2);
c = Page.FindControl(ctrlStr);
}
else
{
c = Page.FindControl(ctl);
}
if (c is System.Web.UI.WebControls.Button ||
c is System.Web.UI.WebControls.ImageButton)
{
control = c;
break;
}
}
}
if (control != null)
return control.ID;
else
return string.Empty;
}
}
and change this line:
public partial class WebForm2 : MyPageBaseClass
Now when I click on icons grid view disappears...(STRANGE...) and nothing happened. When I comment specified line then every thing will be fine...(STRANGE...).
In GetPostBackControlName nothings changed to Request but I don't know why this happened. I checked and I see if I haven't RegisterStartupScript in click event every thing is fine. Please help we to solve this problem.
Thanks
when I click on icons grid view disappears...
ASP.Net page class object instances only live long enough to serve one HTTP request, and each HTTP request rebuilds the entire page by default.
Every time you do a postback, you have a new HTTP request and therefore a new page class object instance and a completely new HTML DOM in the browser. Any work you've done for a previous instance of the page class — such as bind a list of addresses to a grid — no longer exists.
You could fix this by also rebuilding your grid code on each postback, but what I'd really do is skip the whole "RegisterStartupScript" mess and instead make the grid links open the window directly, without a postback at all.
The problem is related to OnInit event. I replaced it with OnPreLoad and every things is fine now.
For search engines: OnInit event has conflict with RegisterStartupScript
There are several posts on here with similar titles, but none that I have found actually exhibit the same behavior I'm seeing. I'm using buttons with MultiView as my navigation to give the appearance of tabs. The page loads, no problem. I can switch tabs, no problem. The issue I'm having occurs only when I press a different navigation button while a gridview is actively loading. If I wait for the gridview to fully load, I get no errors.
The full error I'm receiving is: Invalid postback or callback argument. Event validation is enabled using in configuration or <%# Page EnableEventValidation="true" %> in a page. For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected, use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation.
If I add the following, it does resolve my issue. However, I'm trying to avoid this if at all possible.
<%# Page ... EnableEventValidation = "false" />
default.aspx
<form id="form1" runat="server">
<table width="100%" align="center">
<tr style="background-color:#E9E9E9;">
<td>
<asp:Button Text="Tab1" BorderStyle="None" ID="Tab1Button" CssClass="Initial" runat="server"
OnClick="Tab1Button_Click" />
<asp:Button Text="Tab2" BorderStyle="None" ID="ConflictButton" CssClass="Initial" runat="server"
OnClick="ConflictButton_Click" />
<asp:Button Text="Tab3" BorderStyle="None" ID="Tab3Button" CssClass="Initial" runat="server"
OnClick="Tab3Button_Click" />
<asp:Button ID="AffiliateAddButton" runat="server" Text="Add" />
<asp:MultiView ID="MainView" runat="server">
<asp:View ID="View1" runat="server">
<table class="TabContent"><tr><td>
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="true" DataSourceID="SqlDataSource1">
</asp:GridView>
</td></tr></table>
</asp:View>
<asp:View ID="View2" runat="server">
<table class="TabContent">
<tr>
<td>
View 2
</td>
</tr>
</table>
</asp:View>
<asp:View ID="View3" runat="server">
<table class="TabContent">
<tr>
<td>
View 3
</td>
</tr>
</table>
</asp:View>
</asp:MultiView>
</td>
</tr>
</table>
</form>
default.cs
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
Tab1Button.CssClass = "Clicked";
MainView.ActiveViewIndex = 0;
LoadGrid();
}
}
protected override void Render(HtmlTextWriter writer)
{
// Register controls for event validation
foreach (Control c in this.Controls)
{
this.Page.ClientScript.RegisterForEventValidation(
c.UniqueID.ToString()
);
}
base.Render(writer);
}
private void LoadGrid()
{
SqlDataSource1.CancelSelectOnNullParameter = false;
GridView1.DataSourceID = null;
GridView1.DataSourceID = "SqlDataSource1";
GridView1.DataBind();
}
private void ButtonsControl(string tab)
{
if(tab == "Tab1")
{
AffiliateAddButton.Visible = true;
Tab1Button.CssClass = "Clicked";
ConflictButton.CssClass = "Initial";
Tab3Button.CssClass = "Initial";
LoadGrid();
}
if (tab == "Tab2")
{
AffiliateAddButton.Visible = false;
Tab1Button.CssClass = "Initial";
ConflictButton.CssClass = "Clicked";
Tab3Button.CssClass = "Initial";
GridView1.DataSourceID = null;
GridView1.DataBind();
}
if (tab == "Tab3")
{
AffiliateAddButton.Visible = false;
Tab1Button.CssClass = "Initial";
ConflictButton.CssClass = "Initial";
Tab3Button.CssClass = "Clicked";
GridView1.DataSourceID = null;
GridView1.DataBind();
}
}
protected void Tab1Button_Click(object sender, EventArgs e)
{
ButtonsControl("Tab1");
MainView.ActiveViewIndex = 0;
}
protected void ConflictButton_Click(object sender, EventArgs e)
{
ButtonsControl("Tab2");
MainView.ActiveViewIndex = 1;
}
protected void Tab3Button_Click(object sender, EventArgs e)
{
ButtonsControl("Tab3");
MainView.ActiveViewIndex = 2;
}
What I ended up doing was two things:
Added paging. Ideally I didn't want this in this specific scenario but limiting my page to 500 lines made it load fast enough to almost eliminate this.
Switched from multiview to frameset. Again, not an ideal option, but works in my given scenario.
Good morning .
I search many times before posting here .
I am working on a project like a survey [Questions and Answers]
I am able to get all questions in datalist , now i am searching a way to display the answers in Radio button list inside each question .
here is page load
protected void Page_Load(object sender, EventArgs e)
{
string CS = ConfigurationManager.ConnectionStrings["TMConnectionString"].ConnectionString;
SqlConnection con = new SqlConnection(CS);
//Getting All Questions
SqlDataAdapter dr = new SqlDataAdapter("select * from Question ", con);
DataSet ds = new DataSet();
dr.Fill(ds, "Qs");
OuterDataList.DataSource = ds.Tables["Qs"];
OuterDataList.DataBind();
}
here is page body
<body>
<form id="form1" runat="server">
<h1>Test Page</h1>
<asp:DataList ID="OuterDataList" RunAt="server">
<ItemTemplate>
<h4><%# DataBinder.Eval (Container.DataItem, "Question") %></h4>
<asp:RadioButtonList ID="RadioButtonList1" runat="server"></asp:RadioButtonList>
</ItemTemplate>
</asp:DataList>
</form>
i dont know how to bind radiobuttonlist and group the answers .
note : the common column between Question table and Answer table is Question_id
Firt will make a template like below.
<asp:DataList runat="server" ID="DataList1" RepeatDirection="Vertical"
DataKeyField="QuestionID" onitemdatabound="DataList1_ItemDataBound">
<ItemTemplate>
<table>
<tr>
<td>
<%# Eval("Question") %>
</td>
</tr>
<tr>
<td>
<asp:RadioButtonList runat="server" ID="RadioButtonList1">
</asp:RadioButtonList>
</td>
</tr>
</table>
</ItemTemplate>
After that using DataList1_ItemDataBound you can bind your answers.
protected void DataList1_ItemDataBound(object sender, DataListItemEventArgs e)
{
if (e.Item.ItemType == ListItemType.Item)
{
RadioButtonList RadioButtonList1 = (RadioButtonList)e.Item.FindControl("RadioButtonList1");
//Get questionID here
int QuestionID = Convert.ToInt32(DataBinder.Eval(e.Item.DataItem, "QuestionID"));
//pass Question ID to your DB and get all available options for the question
//Bind the RadiobUttonList here
}
}
I want to get values from dynamically added user control
I'm trying but count comes as 0 so condition failed
Code:
private const string VIEWSTATEKEY = "ContactCount";
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
//Set the number of default controls
ViewState[VIEWSTATEKEY] = ViewState[VIEWSTATEKEY] == null ? 1 : ViewState[VIEWSTATEKEY];
//Load the contact control based on Vewstate key
LoadContactControls();
}
}
private void LoadContactControls()
{
for (int i = 0; i < int.Parse(ViewState[VIEWSTATEKEY].ToString()); i++)
{
rpt1.Controls.Add(LoadControl("AddVisaControl.ascx"));
}
}
protected void addnewtext_Click(object sender, EventArgs e)
{
ViewState[VIEWSTATEKEY] = int.Parse(ViewState[VIEWSTATEKEY].ToString()) + 1;
LoadContactControls();
}
EDIT
Here is the problem count takes as 0 so condition failed loop comes out
private void saveData()
{
foreach (var control in rpt1.Controls)
{
var usercontrol = control as VisaUserControl;
string visaNumber = usercontrol.TextVisaNumber;
string countryName = usercontrol.VisaCountry;
}
}
}
protected void Save_Click(object sender, EventArgs e)
{
saveData();
}
.ascx.cs
public string TextVisaNumber
{
get { return txtUser.Text; }
set { txtUser.Text = value; }
}
public string VisaCountry
{
get { return dropCountry.SelectedValue; }
set { dropCountry.SelectedValue = value; }
}
.ascx
<%# Control Language="C#" AutoEventWireup="true" CodeBehind="AddVisaControl.ascx.cs" EnableViewState="false" Inherits="Pyramid.AddVisaControl" %>
<%# Register assembly="BasicFrame.WebControls.BasicDatePicker" namespace="BasicFrame.WebControls" tagprefix="BDP" %>
<div id="divreg" runat="server">
<table id="tbl" runat="server">
<tr>
<td>
<asp:Label ID="lbl2" runat="server"></asp:Label>
</td>
</tr>
<tr>
<td> Visa Number:</td>
<td><asp:TextBox ID="txtUser" Width="160px" runat="server"/></td>
<td> Country Name:</td>
<td><asp:DropDownList ID="dropCountry" Width="165px" runat="server"></asp:DropDownList></td>
</tr>
<tr>
<td> Type of Visa:</td>
<td><asp:DropDownList ID="dropVisa" Width="165px" runat="server"></asp:DropDownList></td>
<td> Type of Entry:</td>
<td><asp:DropDownList ID="dropEntry" Width="165px" runat="server"></asp:DropDownList></td>
</tr>
<tr>
<td> Expiry Date</td>
<td><BDP:BasicDatePicker ID="basicdate" runat="server"></BDP:BasicDatePicker></td>
<td>
<asp:Button ID="btnRemove" Text="Remove" runat="server" OnClick="btnRemove_Click" />
</td>
</tr>
</table>
</div>
Any ideas? Thanks in advance
You need to create public property in your user control.
And access that property through the id of the user control.
See this and This question.
Always assign id to the controls you are adding its a good practice.
Control ctrl = Page.LoadControl("~/UserControls/ReportControl.ascx");
ctrl.ID = "UniqueID";
Also since you are adding controls dynamically you need to manage view state of the same, or add third party controls who do this part for you.
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
}