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Dynamically created linkbuttons' common event not firing

Whenever DropDownList SelectedIndexChanged, I am adding LinkButtons as ul-li list in codebehind. Each linkbuttons were assigned with IDs and a common Click event. Problem is code in Click event is not executed or maybe event is not triggered. My code below: [Edit] I tried like this as suggested in other posts (dynamically created list of link buttons, link buttons not posting back)
protected void ddl_SelectedIndexChanged(object sender, EventArgs e)
{
populate();
}
protected override void OnInit(EventArgs e)
{
base.OnInit(e);
populate();
}
void populate()
{
HtmlGenericControl ulList = new HtmlGenericControl("ul");
panel.Controls.Add(ulList);
foreach (DataRow dr in drc)
{
HtmlGenericControl liList = new HtmlGenericControl("li");
ulList.Controls.Add(liList);
var lnk = new LinkButton();
lnk.ID = dr["col1"].ToString();
lnk.Text = dr["col1"].ToString();
lnk.Click += Clicked;
liList.Controls.Add(lnk);
}
}
private void Clicked(object sender, EventArgs e)
{
var btn = (LinkButton)sender;
label1.Text = btn.ID.ToString();
}
Im missing something. Any help please.

Here the issue is with the ViewState. When the selected index of the dropdownlist changes there is a postback which takes place and the previous state is lost, so at this point you have to maintain the state of the controls.
Now in your code actually the state of the control is lost and so the click event does not fire. So the solution is to maintain the state of the controls.
The Below is a working example, you can just paste it and try.
This is my page load.
protected void Page_Load(object sender, EventArgs e)
{
for (var i = 0; i < LinkButtonNumber; i++)
AddLinkButton(i);
}
Similarly you have to maintain the state of the previously added control like this.
private int LinkButtonNumber
{
get
{
var number = ViewState["linkButtonNumber"];
return (number == null) ? 0 : (int)number;
}
set
{
ViewState["linkButtonNumber"] = value;
}
}
The below is my SelectedIndexChanged Event for the DropDownList
protected void Example_SelectedIndexChanged(object sender, EventArgs e)
{
AddLinkButton(LinkButtonNumber);
LinkButtonNumber++;
}
I have a function which dynamically creates the controls, which is called on the page load and on SelectedIndexChanged.
private void AddLinkButton(int index)
{
LinkButton linkbutton = new LinkButton { ID = string.Concat("txtDomain", index) };
linkbutton.ClientIDMode = ClientIDMode.Static;
linkbutton.Text = "Link Button ";
linkbutton.Click += linkbutton_Click;
PanelDomain.Controls.Add(linkbutton);
PanelDomain.Controls.Add(new LiteralControl("<br />"));
}
And this is the Click event for the LinkButton
void linkbutton_Click(object sender, EventArgs e)
{
//You logic here
}

I solved it using brute code lol.
Since controls' event were not bound on postback then we recreate them on postback. So in my Page_Load I called the module that re-creates the controls, thus binding them to corresponding event. This works, but...
Re-creating these controls create duplicates (Multiple Controls with same ID were found) and you will get into trouble in instances of finding a control by ID like using panel.FindControl.
To remedy this scenario, I put a check if same control ID already existed before recreating them, and voila! It works.
protected void Page_Load(object sender, EventArgs e)
{
populate();
}
void populate()
{
HtmlGenericControl ulList = new HtmlGenericControl("ul");
panel.Controls.Add(ulList);
foreach (DataRow dr in drc)
{
HtmlGenericControl liList = new HtmlGenericControl("li");
ulList.Controls.Add(liList);
if (liList.FindControl(dr["col1"].ToString()) == null)
{
var lnk = new LinkButton();
lnk.ID = dr["col1"].ToString();
lnk.Text = dr["col1"].ToString();
lnk.Click += Clicked;
liList.Controls.Add(lnk);
}
}
}

UserControl Click event not firing

Hi this is my aspx page loading some values to the user control
protected void Page_Load(object sender, EventArgs e)
{
}
this is the usercontrol where i am loading and sending the values in find click event
protected void BtnFind_Click(object sender, EventArgs e)
{
Usr_BPOP BPOP = (Usr_BPOP)Page.LoadControl("~/Usr_BPOP.ascx");
BPOP.Date = txtDate.Text.Trim();
BPOP.DocNo = txtDocNo.Text.Trim();
BPOP.Code = txtCode.Text.Trim();
BPOP.Name = txtName.Text.Trim();
BPOP.Partcode = txtPartNo.Text.Trim();
if (chkReprint.Checked)
{
BPOP.BtnReprintVisible = true;
BPOP.BtnSaveVisible = false;
}
divControls.Controls.Clear();
PlaceHolder1.Controls.Add(BPOP);
}
this is my Usr_BPOP.ascx:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
btnReprint.Click += new EventHandler(btnReprint_Click);
}
btnReprint.Visible = false;
btnSave.Visible = BtnSaveVisible;
btnReprint.Visible = BtnReprintVisible;
if (btnReprint.Visible == false)
{
btnReprint.Text = "Print";
btnReprint.Visible = true;
}
table = new DataTable();
table.Columns.Add("DocNum", typeof(string));
table.Columns.Add("DocEntry", typeof(string));
table.Columns.Add("LineNum", typeof(string));
table.Columns.Add("PartNo", typeof(string));
table.Columns.Add("ItemDesc", typeof(string));
table.Columns.Add("QTR", typeof(string));
table.Columns.Add("QTP", typeof(string));
table.Columns.Add("Chk", typeof(bool));
table.Columns.Add("BarCode", typeof(string));
Datalayer dl = new Datalayer();
DataTable dttable = new DataTable();
if (!BtnSaveVisible && BtnReprintVisible)
BtnSaveVisible = true;
dttable = dl.GetPOItem(date, docNo, code, name, partcode, BtnReprintVisible, !BtnSaveVisible).Tables[0];
foreach (DataRow dr in dttable.Rows)
{
table.Rows.Add(dr["DocNum"].ToString(), dr["DocEntry"].ToString(), dr["LineNum"].ToString(), dr["PartNo"].ToString(),
dr["ItemDesc"].ToString(), dr["QTR"].ToString(), dr["QTP"].ToString(), Convert.ToBoolean(dr["Chk"]), dr["Barcode"].ToString());
}
if (table != null && table.Rows.Count > 0)
{
grdlistofitems.DataSource = table;
Session["Table"] = table;
grdlistofitems.DataBind();
}
else
{
}
}
this is the reprint button click event when i cilck this event it is not firing:
void btnReprint_Click(object sender, EventArgs e)
{
}

Since you are not setting the ID of the control, it is generated anew every time the control added to the page. The generated ID might not be the same, and therefore the sender of the event cannot be recognized. So first thing you should do is assign an ID explicitly:
Usr_BPOP BPOP = (Usr_BPOP)Page.LoadControl("~/Usr_BPOP.ascx");
BPOP.ID = "SomeID";
Secondly, assignment of the event handler should be done very time the control is created - that is, on every request, does not matter whether this is a postback or not - otherwise ASP.NET will not be able to determine what method should be called when the event is fired:
protected void Page_Load(object sender, EventArgs e)
{
// No check for postback here
btnReprint.Click += new EventHandler(btnReprint_Click);
Update. There is one more reason why this code does not behave as expected. The BPOP control is added to the page only on btnFind click. When the postback is caused by anything else, including btnReprint, on the response page generation BPOP control is not added to the page at all. If there is no control on the page - obviously its methods, including event handlers, cannot be triggered.
Here is quick and dirty fix for this situation. It should be applied to the page code where BPOP control is added:
protected void Page_Load(object sender, EventArgs e)
{
bool? addBPOP = ViewState["AddBPOP"] as bool?;
if (addBPOP.HasValue && addBPOP.Value)
{
AddBPOP();
}
}
protected void BtnFind_Click(object sender, EventArgs e)
{
AddBPOP();
ViewState["AddBPOP"] = true;
}
protected void AddBPOP()
{
Usr_BPOP BPOP = (Usr_BPOP)Page.LoadControl("~/Usr_BPOP.ascx");
BPOP.ID = "BPOPID";
BPOP.Date = txtDate.Text.Trim();
BPOP.DocNo = txtDocNo.Text.Trim();
BPOP.Code = txtCode.Text.Trim();
BPOP.Name = txtName.Text.Trim();
BPOP.Partcode = txtPartNo.Text.Trim();
if (chkReprint.Checked)
{
BPOP.BtnReprintVisible = true;
BPOP.BtnSaveVisible = false;
}
divControls.Controls.Clear();
PlaceHolder1.Controls.Add(BPOP);
}

Change:
void btnReprint_Click(object sender, EventArgs e)
{
}
To
protected void btnReprint_Click(object sender, EventArgs e)
{
}

Create session in gridview cell

i have a gridview with tempaltefield buttons,
i want to create a session with value of a cell in selected button row ,
can anyone help me i tryed this but didnt work:
protected void ImageButton1_Click1(object sender, ImageClickEventArgs e)
{
Session["mysession"] = GridView1.SelectedRow.Cells[1].Text;
}

First of all, if it's just a imagebutton in a templatefield, actually you don't select de row. This line will problably throw an exception because SelectedRow is null.
But if you are using a command to select, that's correct. Maybe your event (ImageButton1_Click1) is not assigned to your image (OnClick).
You can try something like this:
protected void Page_Load(object sender, EventArgs e)
{
try
{
//Add and event RowDataBound
grvGrid.RowDataBound += new GridViewRowEventHandler(grvGrid_RowDataBound);
}
catch
{
//...throw
}
}
protected void grvGrid_RowDataBound(object sender, GridViewRowEventArgs e)
{
try
{
if (e.Row.RowType == DataControlRowType.Header)
{
//...
}
if (e.Row.RowType == DataControlRowType.DataRow)
{
//Add an ImageButton foreach row in GridView
ImageButton ibtImageAlt = new ImageButton();
ibtImageAlt.ImageUrl = "App_Images/y.gif";
//ImageButton's ID will be the index of the row
ibtImageAlt.ID = e.Row.RowIndex.ToString();
ibtImageAlt.ForeColor = System.Drawing.Color.White;
ibtImageAlt.Font.Overline = false;
ibtImageAlt.Click += ibtImageAlt_Click;
}
}
catch
{
//...throw
}
}
protected void ibtImageAlt_Click(object sender, EventArgs e)
{
try
{
//Catch the ImageButton ID and the row in GridView
//An example to catch the value of the row selected by the ImageButton
Int32 intIndexRow = Convert.ToInt32(((ImageButton)sender).ID);
String strTest = grvGrid.Rows[intIndexRow].Cells[0].Text;
}
catch
{
//...throw
}
}

Why won't my SelectedIndexChanged event fire in Button_Click?

protected void Button1_Click(object sender, EventArgs e)
{
TableRow tb = new TableRow();
TableCell tc = new TableCell();
DropDownList db = new DropDownList();
db.Items.Add("Bangalore");
db.Items.Add("Mandya");
db.Items.Add( "Hassan");
tc.Controls.Add(db);
tb.Controls.Add(tc);
Table1.Controls.Add(tb);
db.SelectedIndexChanged += db_SelectedIndexChanged;
db.AutoPostBack = true;
}
private void db_SelectedIndexChanged(object sender, EventArgs e)
{
label.text = "welcome";
}
When this code executes in the Button1_Click event, db_SelectedIndexChanged doesn't execute. However, when I place the same Button1_Click code block in the Page_Load event, db_SelectedIndexChanged executes.
What may be the reason behind this?

Try to put
db.SelectedIndexChanged += db_SelectedIndexChanged;
db.AutoPostBack = true;
In the Page_Load event.
Don't wrap db.SelectedIndexChanged += db_SelectedIndexChanged; in !Page.IsPostBack as the events need to be wired up on each load

You are creating a dynamic control. The event will not fire unless you create the control in the PreInit method of the page.
protected void Page_PreInit(object sender, EventArgs e)
{
DropDownList db = new DropDownList();
db.Items.Add("Bangalore");
db.Items.Add("Mandya");
db.Items.Add( "Hassan");
db.SelectedIndexChanged += db_SelectedIndexChanged;
db.AutoPostBack = true;
tc.Controls.Add(db);
}
Check Page Life cycle for more info.

protected void Button1_Click(object sender, EventArgs e)
{
TableRow tb = new TableRow();
TableCell tc = new TableCell();
DropDownList db = new DropDownList();
db.Items.Add("Bangalore");`
db.Items.Add("Mandya");
db.Items.Add( "Hassan");
tc.Controls.Add(db);
tb.Controls.Add(tc);
Table1.Controls.Add(tb);
db.SelectedIndexChanged += db_SelectedIndexChanged;
db.AutoPostBack = true;
db_SelectedIndexChanged(null,null); // use this line, i hope it will work now.
}
private void db_SelectedIndexChanged(object sender, EventArgs e)
{
label.text = "welcome";
}
You can try this one.

Textbox in apsx.cs file won't update a changed text

I have a web application consisting of an aspx-file.
On page load two textboxes are filled with data (a "username" and a "password"). This works.
On a button click it should save the textboxes' text. But for some reason the text of the textboxes isn't updated if I have changed it manually meanwhile (by typing in some letters with my keyboard).
Why is that? And how can I tell my program to regard my changes?
My code is:
protected void Page_Load(object sender, EventArgs e)
{
CredentialsManager cm = new CredentialsManager();
TextBox_Benutzername.Text = cm.Username;
TextBox_Passwort.Text = cm.Password;
}
protected void Button_Speichern_Click(object sender, EventArgs e)
{
CredentialsManager cm = new CredentialsManager();
cm.setCredentials(TextBox_Benutzername.Text, TextBox_Passwort.Text);
}
EDIT:
It works with this improvement:
protected void Page_Load(object sender, EventArgs e)
{
if(!IsPostBack)
{
CredentialsManager cm = new CredentialsManager();
TextBox_Benutzername.Text = cm.Username;
TextBox_Passwort.Text = cm.Password;
}
}
For further information, see answers below. Thanks everyone!

Try checking for a postback -
private void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
CredentialsManager cm = new CredentialsManager();
TextBox_Benutzername.Text = cm.Username;
TextBox_Passwort.Text = cm.Password;
}
}
Your Page_Load code will currently run after every button click (or postback), and overwrite the values you have manually added.

Try this,
protected void Page_Load(object sender, EventArgs e)
{
if(!IsPostBack){
CredentialsManager cm = new CredentialsManager();
TextBox_Benutzername.Text = cm.Username;
TextBox_Passwort.Text = cm.Password;
}
}

You are assiging the value to the textboxes on every page load instead of firt page load.
Change the Page_Load method to :
protected void Page_Load(object sender, EventArgs e)
{
if(!IsPostBack)
{
CredentialsManager cm = new CredentialsManager();
TextBox_Benutzername.Text = cm.Username;
TextBox_Passwort.Text = cm.Password;
}
}

I think the problem is that you are creating a new CredentialsManager each and every time that the page is loaded (I assume that a new CredentialsManager has an empty Username and Password fields). You should only do that on new page loads, and not when the page is refreshed because of a button click. That is determined with the Page.IsPostBack property, so you moght need to do:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
CredentialsManager cm = new CredentialsManager();
TextBox_Benutzername.Text = cm.Username;
TextBox_Passwort.Text = cm.Password;
}
}