I want to add more controls to page based on some specific conditions. Those controls don't need any ViewState or binding data, it is as simple as a static link. I wonder where I could write the code: inside OnLoad or OnInit method? and why? If I place it inside OnLoad, should I add following line: if (IsPostBack) return; before any initialization code?
View 4 Replies
I am using C#.
I am having below code in C#:
protected override void OnInit(EventArgs e)
{
try
{
if (Session["boolSignOn"].ToString() == "true".ToString())
{
lblPanelOpen.Text = Session["panelOpen"].ToString();
}
else
{
lblPanelOpen.Text = Session["panelOpen"].ToString();
}
}
catch (Exception ex)
{
Logger.Error("Error processing request:" + ex.Message);
}
}
protected override void OnLoad(EventArgs e)
{
try
{
if (!string.IsNullOrEmpty(Session["panelOpen"].ToString()))
{
lblPanelOpen.Text = string.Empty;
Session.Remove("panelOpen");
}
}
catch (Exception ex)
{
Logger.Error("Unable to remove the session variable:" + ex.Message);
}
}
In above code I am having a Session["panelOpen"] variable which is created from another user control and once my page is trying to render, I am storing Session["panelOpen"] in my hidden lblPanelOpen.Text on page OnInit() method, however when page is loaded completely then I am trying to remove the session variable.
Found this question on an interview siteGiven the following methods of the ASP .Net Page class, in which of them would you attach an event handler to an event published by a control on the web page?
View 1 RepliesI am trying to dynamically add buttons to a gridview during the onload event.
protected override void OnLoad(EventArgs e)
{
CreateFilterRows(this.Controls[0] as Table);
[code]...
I have a dynamic Table which contain 8 rows and 8 Colums
Table t = new Table();
TableRow rr = new TableRow();
TableCell cc = new TableCell();
and in the each Cell CC I add a dynamic Button(Or Linkbtn)
LinkButton LB1 = new LinkButton();
LB1.Text = "AM";
LB1.ID ="Link1";
cc.Controls.Add(LB1);
rr.Cells.Add(cc);
LB1.Click += new EventHandler(LB1_Click);
t.Rows.Add(rr);
i have a table with 8 rows , 8 colums and each cell contain a LinkButton (which diffrent in IDs) I want to add Lable in the same cell of this LinkBtn(LB1) which it clicked but I cann't What shoud I write here?
void LB1_Click(object sender, EventArgs e)
{
// throw new NotImplementedException();
}
I have a page I need to build out where depending on the selection the user made on a form on the page prior it displays a different set of questions for them to answer.
So say the user selects Reason A from the form on page edit, then it needs to display Questions 1 and 2 on page edit_confirmation. But if they select Reason B then it needs to display Questions 3 and 4.
I'm grabbing the reason code from the query string and have a switch statement set up, but I can't find anywhere how to output different controls. If Questions 1 and 2 are supposed to show up, one could be a text box and the other a checkbox, but if questions 3 and 4 are supposed to show up one may need to be a dropdown list and a checkbox.
EDIT: I'm going to try some of the below suggestions and will be back to mark the answer and upvote accordingly. Thank you all for the quick response.
EDIT EDIT: Both rlb.usa and AndrewVos's answers worked equally well. I went with Andrew's since it seemed like the more "proper" way of doing it.
I'm listing some controls at my web page dynamically, either I'm adding newline with Label's.
Label newLine = new Label();newLine.Text = "<br/>"; myPanel.Controls.Add(newLine);
How can I do it in a different way?
So am adding fields in the code behind and now want to add required field validators. Kicker, I think comes into play becasue all this is in a master page. So even though I may set the id of the textbox to say tb4, it's no longer tb4. So when I add the required field validator and tell it the control to validate is tb4, I get the yellow screen of death telling me thtat tb4 does not exist... cause it's the long huge master page ID. What do I do?
View 13 RepliesI am adding controls dynamically in my webpage.
I add them in onload method.
everything is working fine..
But I m a bit confused about how it works..
I have read in so many articles that all controls get their values from viewstate before load event. Then how my dynamically added controls get their values when i am adding them in OnLoad event ie after LoadPostData event.
I have a panel with two static buttons. A "Ok" button and a "Cancel" button". Depending on ther client actions, one or more controls will be added to the panel. Is there a way I can add the dynamic controls above the static ones?
View 2 RepliesThere are two fields and a button :
1)text box for the caption.
2)drop down list to select the control to be added.
3)button is an ADD button .
when the "ADD" button is clicked the text entered in the "caption" text box has to appear in the first cell of the first row in the table and the control selected from the dropdown list has to be added to the second cell of the same row. similarly many such captions and controls have to be dynamically addded to the successive rows of the table as per user selection ( note: the previously selected control and caption label must persist on furthur selections .
how do i go about the adding controls and the text into the table part ?
I've got an image URL in a gridView which retrieves the name of a file, but I need to add some text to the start and end of the value returned. This is the code so far:
[Code]....
The image URL renders as 'filename.png', but I need to add 'about-us/images/' before it.
I have what is probably a basic question but I do not understand if/why there is a difference. I have a simple asp.net page with a staticly created DropDownList and Panel control. The user can select one of three options if the drop down (Employee, Company, Address) which should load the respective custom UserControl into the panel below. By default, I have the Employee control selected in the drop down and it should be displayed on the intial Page Load (!Page.IsPostBack).
If I do the following it performs the desired behavior on the intial load:
[Code]....
If I try the following, the User Control does not appear on the initial page load:
[Code]....
I noticed if I do it with a textbox instead of a UserControl, it works however:
[Code]....
I assume there is some sort of behavioral difference in the way the loading is done between a UserControl and WebControl.
I have a Gridview on my aspx page. On my page_load event I check for a record in the database, if the record exists for that row in the gridview I would like to add a new column in the same gridview and add a button control to it. This adding of new column in the Gridview should happen in the codebehind (c#). see the code I wrote for this, but when I run it, it does not create any column on the gridview page.
[Code]....
i have read and used this script.Adding Dynamic Rows in ASP.Net GridView Control with TextBoxes..it is very usful to me but i want to fetch data from sqll database and fill the newest row with it. the past row data hav to be remain same. becoz of the same name of textbox it happens. whenever i try to fetch data from database and fill textbox all rows get updated with the same data.
View 1 RepliesI have created an Asp.Net Ajax Server Control that will be dropped on several aspx pages. I have created an HTMLGenericControl within the OnInit method of the control. This control is a div. Within the code I also need to add an onclick event to a button so that this div is shown.
However, when I call divName.ClientID within the control to pass it to the javascript it doesn't include the part of the ID before the "divName" section of the rendered control id - ct01_ct01_divName.Here is part of the OnInit() method within the ASP.Net Ajax Server Control.[Code]....
I'm trying to add an DropDownList to a DetailsView by code, because i'm writing a solution that let's the user select an table and view your records and edit them, some of theese tables, have a foreign key column and the user must have to select some item in the list.
Below is my sample code:
[Code]....
the code above is working correctly, when the user click in the buttons New or Edit , the DetailsView opens correctly, showing the DropDownlist, but when the user click in the buttons update or insert , an error occurs, the viewState cannot be loaded:
Failed to load viewstate. The control tree which viewstate is being loaded must match the control tree used to save viewstate during the previous request. For example, when controls are added dynamically, the controls added during a post must match the type and position of the controls added during the initial request.
As per you sample : [URL] ...
How do I add maximum rows that can be added ?
I was having a discussion with a co worker about some controls I implemented. He objected to my use of dynamicly instantiating controls in the code behind, because it will be slower than specifying the control in the markup. I thought he was talking about output cacheing which to my understanding only caches the rendered output of a page not the instantiated Page object. He said no its a different type of caching. Unfortunately he was unable to give me any documentation to backup the claim so I am wondering if anyone here has ever hear of any such type of caching, and if so is there any documentation on it that I can refer to.
View 5 RepliesI am using this reference to make some application .. In this article we can only save with varchar data types
So how to use some other data types like datetime, money, int..or how to use parameters to convert data.
[URL] ....
I want to call a javascript function at onload event of gridview..But I am getting Compilation error. How can I do this?
Basically I am using a javascript in .aspx page which have a master page. I want to get the value from javascript in code behind.
how to retrieve from the server-side contained a table html constructed this way:
<table id="myTable" >
<tr>
<th> <input type="text" value="name"/></th>
<th> <input type="text" value="quantity" /> </th>
</tr>
<tr>
<th> <input id="name_1" value="phone" /> </th>
<th> <input id="quantity_1" value="15" /> </th>
</tr>
<tr>
<th> <input id="name_2" value="mp3" /> </th>
<th> <input id="quantity_2" value="26" /> </th>
</tr>
</table>
I can not make use of <asp:Table> ... because for technical reasons I did not find a solution following this post: [URL]
How can retrieve the contents values of my table (dynamic) for each row. Rows will be added in client-side js
How can I add rows in a table from server-side?
if (!Page.IsPostBack)
{
Session["table"] = TableId;
}
else
{
TableId = (Table)Session["table"];
}
protected void btnAddinRow_Click(object sender, EventArgs e)
{
num_row = (TableId.Rows).Count;
TableRow r = new TableRow();
TableCell c1 = new TableCell();
TableCell c2 = new TableCell();
TextBox t = new TextBox();
t.ID = "textID" + num_row;
t.EnableViewState = true;
r.ID = "newRow" + num_row;
c1.ID = "newC1" + num_row;
c2.ID = "newC2" + num_row;
c1.Text = "New Cell - " + num_row;
c2.Controls.Add(t);
r.Cells.Add(c1);
r.Cells.Add(c2);
TableId.Rows.Add(r);
Session["table"] = TableId;
}
in debug I found out the number in the "TableID", but the rows are not drawn. Have you got an idea about this issue?
I have a page with a dynamically created command button. I need to dynamically wire up a click event so I can grab the CommandArgument of the clicked button.
Button b = new Button();
b.ID = "btnTrigger2";
b.CssClass = "hiddenBtn";
b.CommandName = "lbl3";
b.Click += new EventHandler(btnTrigger_Click);
The problem is the last line - I can't wire up an EventHandler this way - I need to use the standard EventArgs instead of CommandEventArgs. There's got to be a way.
EDIT
Figured I'd post the code that finally worked in case anyone else tries to do the same thing.
string tabLoadedScript = string.Empty;
string postBackScript = string.Empty;
string script = " <script language='javascript' type='text/javascript'>" + System.Environment.NewLine;
script += "function clientActiveTabChanged(sender, args) {" + System.Environment.NewLine;
int i = 0;
foreach(TabPanel tp in tc1.Tabs)
{
Button b = new Button();
b.ID = "btn" + tp.ClientID;
b.CssClass = "hiddenBtn";
b.CommandName = tp.ID;
b.Command += btnTrigger_Click;
this.form1.Controls.Add(b);
AsyncPostBackTrigger trg = new AsyncPostBackTrigger();
trg.ControlID = "btn" + tp.ClientID;
tabLoadedScript += "var isTab" + tp.ClientID + "loaded=$get('" + tp.Controls[0].ClientID + "');" + System.Environment.NewLine;
postBackScript += "if(!isTab" + tp.ClientID + "loaded && sender.get_activeTabIndex() == " + i + ") {" + System.Environment.NewLine;
postBackScript += "__doPostBack('" + b.ClientID + "','');}" + System.Environment.NewLine;
i++;
}
script += tabLoadedScript;
script += postBackScript;
script += "}" + System.Environment.NewLine;
script += "</script>";
this.ClientScript.RegisterClientScriptBlock(this.GetType(), "cs", script, false);
protected void btnTrigger_Click(object sender, CommandEventArgs e)
{
System.Threading.Thread.Sleep(2500);
Panel ctrl = (Panel) FindControlRecursive(this, "pnl" + e.CommandName);
ctrl.Visible = true;
}
public static Control FindControlRecursive(Control Root, string Id)
{
if(Root.ID == Id)
return Root;
foreach(Control Ctl in Root.Controls)
{
Control FoundCtl = FindControlRecursive(Ctl, Id);
if(FoundCtl != null)
return FoundCtl;
}
return null;
}
I Have this code in my page, and I want that every NavigateUrl display another page like : simple.aspx? id=1, simple.aspx?id=2, ...
Where id = c
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)
Dim c As Integer = 0
While c < 5
Dim Label1 As New Label()
Dim ltr As New Literal()
Dim link As New HyperLink()
link.NavigateUrl = "simple.aspx"
link.BackColor = Drawing.Color.Aqua
Label1.Text = c.ToString()
ltr.Text = "<br/>"
PlaceHolder1.Controls.Add(Label1)
PlaceHolder1.Controls.Add(link)
PlaceHolder1.Controls.Add(ltr)
c += 1
End While
End Sub
