Lost dynamically added click events to each TableCell in each TableRow - asp.net

I'm developing live-table with WebForms.
I'm adding such control to each TableCell in each TableRow, when I'm adding new rows to the table:
// in some method, which creates the table
TableRow row = new TableRow();
// here goes other cells with text data
TableCell cellActions = new TableCell();
cellActions.ID = "offerActionsOfferId" + enumerator.Current.offerId;
// init button View More for cell
LinkButton buttonViewExpanded = new LinkButton();
buttonViewExpanded.ID = "buttonViewExpandedOfferId" + enumerator.Current.offerId;
buttonViewExpanded.CssClass = "table-actions-button ic-table-edit";
buttonViewExpanded.Click += new EventHandler(buttonViewExpanded_Click);
buttonViewExpanded.ToolTip = "some alt...";
cellActions.Controls.Add(buttonViewExpanded);
/* end of Action Buttons */
...
row.Cells.Add(cellActions);
this.tableMarket.Controls.Add(row);
But there is a fail with the new EventHandler(buttonViewExpanded_Click) method.
Table renders in the ASPX page pretty well and all controls are visible, but a fail occurs when I try to click that LinkButton.
When I've marked a breakpoint and try to catch the execution of my ASP.NET program in the debugger to make some analyse of program work - the page only refreshed and no one breakpoint in the click event handler has been caught.
Why does it occur? And how to make it work?

I cannot test your code; it ties to other classes like InternalApi. However, here is what I found.
You need to figure out the way to load SetTableBodyForSceneMarket in page init.
It basically reload dynamically created controls on post back; otherwise, those controls will be null, and cannot fire events.
protected override void OnInit(EventArgs e)
{
base.OnInit(e);
if(IsPostBack)
{
SetTableBodyForSceneMarket();
}
}
private void SetTableBodyForSceneMarket()
{
...
}

Related

How can I add a new dynamic control on button click?

When I click btnGDynamicCont I want to load the first set of controls, then on each further click of that button, add a new control (textbox) alongside the other ones, so each time it is clicked I am adding a new textbox across state.
Do you know where I should add the creation of the new textbox in order to keep it after each postback?
{
protected void Page_Load(object sender, EventArgs e)
{
if (Convert.ToString(ViewState["Generated"]) == "true")
GenerateDynamicControls();
}
public void GenerateDynamicControls()
{
TextBox txtDynamic = new TextBox();
txtDynamic.ID = "txtDynamic";
txtDynamic.Text = "Dynamic TextBox";
Page.Form.Controls.Add(txtDynamic);
TextBox txtDynamic2 = new TextBox();
txtDynamic2.ID = "txtDynamic2";
txtDynamic2.Text = "Dynamic Textbox";
Page.Form.Controls.Add(txtDynamic2);
}
protected void btnGDynamicCont_Click1(object sender, EventArgs e)
{
if (Convert.ToString(ViewState["Generated"]) != "true")
{
GenerateDynamicControls();
ViewState["Generated"] = "true";
}
else
{
Response.Write("<h2>Controls are already exist in page</h2>");
}
}
}
}
Dynamic controls are usually recreated at the Page_Load method. For more information, please refer to the Dynamically Created Controls in ASP.NET article.
You can refer the below link where a very similar issue is addressed.
unable to add more than one server control dynamically in asp.net
Everytime a postback happens, you should recreate the already existing controls(dynamically added) in your page_load event and the new controls are to be created in the button_click event.
Use some logic to generate ids for the controls for the viewstate to be maintained. VIEWSTATE will be taken care automatically if the ids of the controls generated before and after postback are the same.
One way to keep track of the number of textboxes is to store the count in session.

ListView without items on first pass

I'm building an ASP.NET application. I'm using a ListView to show some Entities however my listview doesn't have items on the first pass. I mean, they show up on the page, but this code only works when I refresh the page:
protected void Page_Load(object sender, EventArgs e)
{
fillFeatures();
}
private void fillFeatures()
{
using (Entities myEntities = new Entities())
{
System.Diagnostics.Debug.Write("Filling features.. \n");
foreach (ListViewItem item in ListView1.Items)
{
System.Diagnostics.Debug.Write("FOR \n");
CheckBox checkbox = (CheckBox)item.FindControl("Checkbox");
TextBox description = (TextBox)item.FindControl("descriptionTextbox");
//Try to get an existing relation
int featureId = Int32.Parse(((Label)item.FindControl("idLabel")).Text);
PlaceHasFeature phf = (from p in myEntities.PlaceHasFeature
where p.place_id == placeId && p.feature_id == featureId
select p).SingleOrDefault();
if (phf != null)
{
System.Diagnostics.Debug.Write("Checking " + phf.Feature.name + "\n");
//Relation exists
checkbox.Checked = true;
description.Text = phf.description;
}
else
{
System.Diagnostics.Debug.Write("Didn't find relation for " + featureId + "\n");
}
}
}
}
Console output:
When I open the link: Filling features...
After refresh: Filling features... FOR FOR FOR (...)
Anyone knows the cause of this?
I suspect the issue is due to the ASP.NET Page Life Cycle, where the page load event occurs before the individual controls load event:
The Page object calls the OnLoad method on the Page object, and then
recursively does the same for each child control until the page and
all controls are loaded. The Load event of individual controls occurs
after the Load event of the page.
I believe you have a couple of options. Move the fillFeatures method to the Page.LoadComplete Event:
The LoadComplete event occurs after all postback data and view-state
data is loaded into the page and after the OnLoad method has been
called for all controls on the page.
Or move the fillFeatures method to the ListBox's DataBound Event. Though I would suspect that the Page.LoadComplete Event is really the better of the two options.

Event for Dynamically created Controls in ASP.Net

I've created an application in which I've created Dynamic Controls on Click Event of a Button. But the dynamically created Control Event will not Fire on Click of it.
Below is the Code I've written.
ImageButton closeImage = new ImageButton();
closeImage.ID = "ID"+ dr["ID"].ToString();
closeImage.AlternateText = "Delete";
closeImage.ImageUrl = "App_Themes/images/CloseButton.png";
closeImage.Attributes.Add("style", "float:right;cursor:pointer;margin: -19px 1px -10px;");
closeImage.EnableViewState = true;
closeImage.CommandName = "Delete";
closeImage.CommandArgument = dr["ID"].ToString();
closeImage.Attributes.Add("runat", "server");
closeImage.OnClientClick = "return confirm('Are you sure you want to remove this');";
closeImage.Click += new ImageClickEventHandler(this.closeImage_click);
protected void closeImage_click(object sender, ImageClickEventArgs e)
{
ImageButton ibDel = (ImageButton)sender;
}
The same code work if its placed on Page_Load(). Is there any other Solution to fire the event.
I would like to suggest that you read up on the following article on MSDN. It's about page lifecycle.The key part is to when controls are created. If the controls are created in the wrong stage, events will not be registered, and thus will not fire.
http://msdn.microsoft.com/en-us/library/ms178472%28v=vs.80%29.aspx

asp:GridView doesn't contain control added in OnRowDataBound

I have problem, I can't get control which I added in DataGrid. I am adding it in OnRowDataBound event like:
protected void RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowState == DataControlRowState.Edit || e.Row.RowState == (DataControlRowState.Alternate | DataControlRowState.Edit))
{
//int cindex = 0;
//for (cindex = 0; cindex < e.Row.Controls.Count; cindex++)
foreach (Control ctl in e.Row.Controls)
{
DataControlFieldCell dcctl = (DataControlFieldCell)ctl;
TableCell tcell = (TableCell)dcctl;
Label lblComment = new Label();
TextBox txtComment = new TextBox();
lblComment.Text = "<br>Comment: ";
dcctl.Controls.Add(lblComment);
dcctl.Controls.Add(txtComment);
//tcell.Controls.Add(lblComment);
//tcell.Controls.Add(txtComment);
//e.Row.Cells[cindex].Controls.Add(lblComment);
//e.Row.Cells[cindex].Controls.Add(txtComment);
What is happening here: there is already exist one TextBox in TableCell by default and I want to add another one TextBox and Label. After the bounding I can see 2 textboxes, I can input data into the both, but when I click Update button, then raises OnRowUpdating event where I can't get my TextBox!
protected void RowUpdating(object sender, GridViewUpdateEventArgs e)
{
grdView.EditIndex = -1;
int counter = 0;
for (counter = 0; counter < grdView.Rows[e.RowIndex].Cells.Count; counter++)
{
foreach (Control ctl in grdView.Rows[e.RowIndex].Cells[counter].Controls)
{
And here I will be getting only default one TextBox (with its value). But my TextBox is disappeared! :(
What could you suggest me here to do?
P.S. I can't use predifined columns, like asp:TemplateField in aspx file, because my table has different amount of rows every time. It is dynamic
The issue is that after you dynamically add a control to a page (or any of the page's child controls such as your datagrid) then you must recreate the controls on the server side on postback. If you don't recreate the controls on the server side, then when the runtime processes the postback it will have no idea where to put the contents of the form post.
So essentially when the page is processing the postback, it sees an HTML field called "gridView1_txtComment" (the actual HTML id is probably something else, I know). But the server side code model only has an instance of gridView1, there isn't an instance of a TextBox named txtComment unless you run the RowDataBound method again to create that control.
I think it has to do with ViewState. Make a templated column out of it, then add the second textbox to the template.
I did it!
Refused of dynamically adding controls in OnRowDataBound, and created dynamical TempalteField columns, which were containing needed to me 2 TextBoxes and Label. (With help of http://www.codeproject.com/KB/aspnet/create_template_columns.aspx)
But after my problem returned back.. On OnRowUpdating event still was not having my added TextBoxes. Finally I've found here notice http://forums.asp.net/p/1537632/3738331.aspx, that it is needed to implement TempalteField-s adding on Page_Load, that helped me to solve the problem!

All of a sudden dynamic created imagebutton's click event wont fire.

I have a page that dynamic create a table of contacts, if the contact got an email I also create an image button with a click event.I have a similar function in the rest of the page that works perfectly. And I used this before without any problems:
protected void CreateContactsList(IQueryable<AA_BranschFinder.Login.vyWebKontaktpersoner> lContacts) // Creates a table in the aspx from an IQueryable List
{
if (1 == 1)
{
htmlTblContactsContent.Rows.Clear();
foreach (var p in lContacts)
{
HtmlTableRow tr = new HtmlTableRow();
HtmlTableCell tdName = new HtmlTableCell();
HtmlTableCell tdCompanyName = new HtmlTableCell();
HtmlTableCell tdEmailAdress = new HtmlTableCell();
tdName.InnerHtml = p.strFnamn + " " + p.strEnamn;
tdCompanyName.InnerHtml = p.strNamn;
//Displays an image if the contacts has an email
if (p.strEpost != null)
{
ImageButton imgEmail = new ImageButton();
imgEmail.CommandArgument = p.intKundID.ToString();
imgEmail.ImageUrl = "images/symbol_letter.gif";
imgEmail.CssClass = "letter";
imgEmail.Click +=new ImageClickEventHandler(imgEmail_Click);
tdEmailAdress.Controls.Add(imgEmail);
}
tr.Cells.Add(tdCompanyName);
tr.Cells.Add(tdEmailAdress);
tr.Cells.Add(tdName);
htmlTblContactsContent.Rows.Add(tr);
}
}
}
void imgEmail_Click(object sender, ImageClickEventArgs e)
{
Breakpoint here
throw new NotImplementedException();
}
The page is living inside a java popup window. But I have paging numbers with similar event creation that works fine. But they are Linkbuttons.
Where are you calling your Create method? You need to do it before the other event handlers run, ideally in the Page.Init. Otherwise, the data posted back to the page are indicated an event firing for a control that doesn't yet exist.
I would also make sure that you give your ImageButton an ID. It will make debugging a lot easier.
imgEmail.ID = String.Format("EmailImageButton_{0}", p.intKundID);
An alternative solution is to look at the __eventtarget and __eventargument parameters in the Request object and see which button was clicked there.
You'll have to create the dynamic controls on EVERY postback. Also check the code in the imgEmail_Click event handler; if you have created the event handler method using .NET IDE's Alt + Shift + F10 method, then there's a chance that you have not removed this line -
throw new Exception("The method or operation is not implemented.");
If I´m not misstaking the imagebutton is a submit kind of button while the linkbutton is an a-tag with javascript. Maybe changing your imagebutton click (ie usesubmitbehaviour set to false) will solve your problem.
Make sure the event handler is added on your postbacks. When adding it just on initial page load, the event won't be handled! (Just encountered and solved this problem myself.)

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