We Keep Coding

ASP.NET Textbox losing values after postback which were set during editing

There's a gridview in my program whose row's data is to be loaded in textboxes if edit is clicked.
Here is the code where I'm filling the data in textboxes after edit is clicked
protected void GV_Parameters_RowEditing(object sender, GridViewEditEventArgs e)
{
GV_Parameters.EditIndex = e.NewEditIndex;
int index = e.NewEditIndex;
IsEditing = true;
Label lbl_frmdate = (Label)GV_Parameters.Rows[index].FindControl("lbl_frmdate") as Label;
Label lbl_todate = (Label)GV_Parameters.Rows[index].FindControl("lbl_todate") as Label;
EditFromDate = lbl_frmdate.Text.ToUpper();
lbl_frm_edit.Text = EditFromDate;
EditToDate = lbl_todate.Text.ToUpper();
lbl_to_edit.Text = EditToDate;
Label lbl = (Label)GV_Parameters.Rows[index].Cells[3].FindControl("lbl_Is_holiday");
string is_holiday = lbl.Text;
Label lbl_std_intime = (Label)GV_Parameters.Rows[index].FindControl("lbl_std_intime") as Label;
Label lbl_std_outtime = (Label)GV_Parameters.Rows[index].FindControl("lbl_std_outtime") as Label;
string[] arr_std_intime;
string[] arr_std_outtime;
if (is_holiday != "1")//working day
{
r_work_holiday.SelectedIndex = 0;
IsHoliday = false;
if (lbl_std_intime.Text != "")
{
arr_std_intime = lbl_std_intime.Text.Split(':');
txt_std_TimeInHours.Text = arr_std_intime[0].ToString();
txt_std_TimeInMins.Text = arr_std_intime[1].ToString();
}
if (lbl_std_outtime.Text != "")
{
arr_std_outtime = lbl_std_outtime.Text.Split(':');
txt_std_TimeOutHours.Text = arr_std_outtime[0].ToString();
txt_std_TimeOutMins.Text = arr_std_outtime[1].ToString();
}
}
else
{
IsHoliday = true;
//r_workingday.Checked = false;
//r_holiday.Checked = true;
r_work_holiday.SelectedIndex = 1;
Label lbl_remarks = (Label)GV_Parameters.Rows[index].FindControl("lbl_remarks") as Label;
txt_holiday_desc.Text = lbl_remarks.Text;
}
collapse_state = "expand";
}
There is a radiobutton list who shows the edited row is holiday or working day,
if user changes the selection in radioButtonList, PostBack occurs and this is the time when all of the texboxes turn blank.
protected void r_work_holiday_SelectedIndexChanged(object sender, EventArgs e)
{
if(r_work_holiday.SelectedIndex==0)
{
IsHoliday = false;
}
else
{
IsHoliday = true;
}
collapse_state = "expand";
}
There's no any method in page load who is clearing the textboxes.
protected void Page_Load(object sender, EventArgs e)
{
if (IsEditing)
{
collapse_state = "expand";
}
if (!Page.IsPostBack)
{
BindYears();
}
}
Please help
Update ::
lbl_frm_edit and lbl_to_edit are not getting reset after postback.
The variable EditFromDate and EditToDate are being set by Viewstate

It's been sometime I worked in ASP controls but if I remember correctly, the content in textboxes are generally cleared on every post back by ASP .NET. The state of the textboxes are not saved.
Here is an answer I found while researching this issue.
You could store the value of the textboxes in ViewState and assign them back on the PageLoad event. Something like
txt_std_TimeOutHours.Text = arr_std_outtime[0].ToString();
txt_std_TimeOutMins.Text = arr_std_outtime[1].ToString();
ViewState["TimeOutHours"] = arr_std_outtime[0].ToString();
ViewState["TimeOutMins"] = arr_std_outtime[1].ToString();
And on the PageLoad event you can do this to restore the values.
if(Page.IsPostBack)
{
txt_std_TimeOutHours.Text = ViewState["TimeOutHours"].ToString();
txt_std_TimeOutMins.Text = ViewState["TimeOutMins"].ToString();
}
Hope this helps!

Link button to display grid view asp.net dynamically

I have to display n grids, n is variable, then I dont know how many grids I'll have.
My problem is, I have to init this grids with Visible false and when click in a button show the grid specific for that button, then how can I link a button to a gridview?
My code that generate the grids:
foreach (List<DataRow> lst in grids)
{
dt = lst.CopyToDataTable();
GridView grv = new GridView();
grv.AlternatingRowStyle.BackColor = System.Drawing.Color.FromName("#cccccc");
grv.HeaderStyle.BackColor = System.Drawing.Color.Gray;
grv.ID = "grid_view"+i;
grv.Visible = false;
grv.DataSource = dt;
grv.DataBind();
Label lblBlankLines = new Label();
lblBlankLines.Text = "<br /><br />";
Label lblTipo = new Label();
string tipoOcorrencia = lst[0]["DESC_OCORRENCIA"].ToString();
tipoOcorrencia = CultureInfo.CurrentCulture.TextInfo.ToTitleCase(tipoOcorrencia);
int quantidade = lst.Count;
lblTipo.Text = tipoOcorrencia + ": " + quantidade;
LinkButton lkBtn = new LinkButton();
lkBtn.ID = "link_button"+i;
lkBtn.Text = "+";
place_grids.Controls.Add(lblBlankLines);
place_grids.Controls.Add(lkBtn);
place_grids.Controls.Add(lblTipo);
place_grids.Controls.Add(grv);
place_grids.DataBind();
i++;
}
Thanks in advance.

Modify your foreach loop as below.
private void GenerateControls()
{
int i = 0;
foreach (List<DataRow> lst in grids)
{
dt = lst.CopyToDataTable();
GridView grv = new GridView();
grv.AlternatingRowStyle.BackColor = System.Drawing.Color.FromName("#cccccc");
grv.HeaderStyle.BackColor = System.Drawing.Color.Gray;
grv.ID = "grid_view" + i;
//grv.Visible = false;//Commented as the grid needs be generated on client side, in order to make it visible from JavaScript/jQuery
grv.Attributes.Add("style", "display:none;");
grv.DataSource = dt;
grv.DataBind();
//Adding dynamic link button
LinkButton lnkButton = new LinkButton();
lnkButton.Text = "button " + i;
//lnkButton.Click += new EventHandler(lnkButton_Click);
lnkButton.ID = "lnkButton" + i;
lnkButton.OnClientClick = "ShowGrid('" + grv.ClientID + "');";
Label lblTipo = new Label();
lblTipo.Text = "text " + i;
lblTipo.ID = "lbl" + i;
tempPanel.Controls.Add(lblTipo);
tempPanel.Controls.Add(grv);
tempPanel.Controls.Add(lnkButton);
tempPanel.DataBind();
i++;
}
}
Then you will have to add a link button click event as below, if you want server side event to fire. (Un-comment the line where event handler is assigned to link button.)
protected void lnkButton_Click(Object sender, EventArgs e)
{
LinkButton lnkButton = (LinkButton)sender;
String index = lnkButton.ID.Substring(lnkButton.ID.Length - 1);
GridView grv = (GridView)tempPanel.FindControl("grid_view" + index);
grv.Visible = true;
}
You will need to add all dynamically added controls in the Page_Init event for maintaining their state. Refer below links can be useful.
Dynamically Created Controls losing data after postback
ViewState in Dynamic Control
Call method GenerateControls from Page_Init event as below.
protected void Page_Init(object sender, EventArgs e)
{
GenerateControls();
}
EDIT :
JavaScript function...
function ShowGrid(gridID) {
document.getElementById(gridID).style.display = ''
}
I have kept the server side click event as it is. But I have commented the line where the event handler is assigned to the link button.

Gridview Edit/Update is not working?

Here i am updating the gridview value but the value is not updating..TextBox txtID,TextBox txtName,TextBox txtAge retains the older value only and the value is not getting updated..Can anyone tel me like what am i doing wrong here
Here is my code
protected void gvTemp_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
CreateDataSkeletton(Convert.ToInt16(Session["intTabIndex"]));
GridViewRow row = (GridViewRow)gvTemp.Rows[e.RowIndex];
int autoid = Int32.Parse(gvTemp.DataKeys[e.RowIndex].Value.ToString());
int id = Convert.ToInt32(gvTemp.DataKeys[e.RowIndex].Values[0].ToString());
activeTabIndex = Convert.ToInt16(Session["activeTabIndex"]);
TextBox txtID = ((TextBox)gvTemp.Rows[e.RowIndex].FindControl("txtId"));
TextBox txtName = (TextBox)gvTemp.Rows[e.RowIndex].FindControl("txtName");
TextBox txtAge = (TextBox)gvTemp.Rows[e.RowIndex].FindControl("txtAge");
dataSetInSession.Tables["Days" + activeTabIndex.ToString()].Rows[e.RowIndex]["ID"] = txtID.Text;
dataSetInSession.Tables["Days" + activeTabIndex.ToString()].Rows[e.RowIndex]["Name"] = txtName.Text;
dataSetInSession.Tables["Days" + activeTabIndex.ToString()].Rows[e.RowIndex]["Age"] = txtAge.Text;
gvTemp.DataSource = dataSetInSession.Tables["Days" + activeTabIndex.ToString()];
gvTemp.DataBind();
gvTemp.EditIndex = -1;
}
and
private void CreateDataSkeletton(int intTabIndex)
{
dataSetInSession = new DataSet();
Session["intTabIndex"] = intTabIndex;
if (Session["dataSetInSession"] != null)
{
dataSetInSession = (DataSet)Session["dataSetInSession"];
}
if (dataSetInSession.Tables["Days" + intTabIndex].Rows.Count > 0)
{
gvTemp.DataSource = dataSetInSession.Tables["Days" + intTabIndex];
gvTemp.DataBind();
}
else
{
gvTemp.DataSource = dataSetInSession.Tables["Days"];
gvTemp.DataBind();
}
temp.Controls.Add(gvTemp);
}
Any suggestion??
EDIT(1):
protected void Page_Init(object sender, EventArgs e)
{
if (!IsPostBack)
{
AddDataTable();
}
dataSetInSession = new DataSet();
if (Session["dataSetInSession"] != null)
{
dataSetInSession = (DataSet)Session["dataSetInSession"];
}
if (Session["dynamicTabIDs"] != null)
{
//if dynamicTabIDs are in session, recreating the Tabs
//that are associated with the Tab IDs
//and adding them to the TabContainer that will contain
//all of the dynamic tabs.
//retrieving the tab IDs from session:
dynamicTabIDs = (List<string>)Session["dynamicTabIDs"];
if (TabContainerContent.ActiveTabIndex == -1)
{
TabContainerContent.ActiveTabIndex = Convert.ToInt16(Session["intTabIndex"]);
}
CreateDataSkeletton(Convert.ToInt16(Session["intTabIndex"]));
//looping through each TabID in session
//and recreating the TabPanel that is associated with that tabID
foreach (string tabID in dynamicTabIDs)
{
//creating a new TabPanel that is associated with the TabID
AjaxControlToolkit.TabPanel tab = new AjaxControlToolkit.TabPanel();
//TabContainerContent.ActiveTabIndex = tab;
//Setting the ID property of the TabPanel
tab.ID = tabID;
//setting the TabPanel's HeaderText
tab.HeaderText = "Days " + (TabContainerContent.Tabs.Count + 1).ToString();
//creating a Label to add to the TabPanel...at this point you'll have to
//create whatever controls are required for the tab...
Label tabContent = new Label();
//Giving the Label an ID
tabContent.ID = "lbl_tab_" + TabContainerContent.Tabs.Count.ToString();
//Setting the Label's text
tabContent.Text = "Tab " + (TabContainerContent.Tabs.Count + 1).ToString();
//Adding the Label to the TabPanel
tab.Controls.Add(tabContent);
//Adding the TabPanel to the TabContainer that contains the dynamic tabs
TabContainerContent.Tabs.Add(tab);
}
}
else
{ //Creating a new list of dynamicTabIDs because one doesn't exist yet in session.
dynamicTabIDs = new List<string>();
}
}
protected void Page_Load(object sender, EventArgs e)
{
}

Read Page Life Cycle
And you will get, that if you want to bind in code-behind, you should do it in Init Event, other wise there are no events will fire.

It seems to be Page.IsPostback problem.Need to add Page.IsPostback property in your page_load like
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
// Put your code inside that.
}
}
Actually your control is getting new value but when you click for updation then it calls old value from page_load.So try to put Page.IsPostback into your page_load event,Just like i mentioned.
I hope it helps.

Multiview has Views added programmatically disappear when trying to change view

I have this code which adds a x number of views to a Multiview control. The Multiview control exist on the page with only one view. on page init I create x number of views with a GridView control added to each of these views when I come to loop through to find which one I want to show the Multiview control says it has only 1 view.
protected void variantRepeat_ItemCommand(object source, RepeaterCommandEventArgs e)
{
if (e.CommandSource.GetType() == typeof(LinkButton))
{
string theID = ((LinkButton)e.CommandSource).CommandArgument.ToString();
ViewCollection views = prodView.Views; //this has only 1 view the one that has been added on the source view of the .aspx page
foreach (View toDisplay in views)
{
if (toDisplay.ID == theID)
prodView.SetActiveView(toDisplay);
}
}
}
The code above loops to find the view and display it. Why do all the views disappear, I've stepped through and at init and after it has finished processing database queries it has x number of views > the 1 in source view.
Why does this control "lose" the views?
Init code:
protected void Page_Load(object sender, EventArgs e)
{
if (Request.QueryString == null || Request.QueryString.Count < 1)
Response.Redirect(Server.MapPath("~/Packages/"));
if (!Page.IsPostBack)
{
if (Request.QueryString["id"].ToString() == string.Empty)
Response.Redirect(Server.MapPath("~/Packages/"));
var id = Server.HtmlEncode(Request.QueryString["id"].ToString());
Guid packID = Guid.Parse(id);
using (var context = new GaleEntities())
{
var thePackage = context.PackageEnts.First(p => p.packageID == packID);
var theVariants = thePackage.Variants;
var mydatasource = new List<PackageEnt> { thePackage };
var myVariantDataSource = new List<Variant>();
foreach (Variant single in theVariants)
{
myVariantDataSource.Add(single);
}
packageForm.DataSource = mydatasource;
variantRepeat.DataSource = myVariantDataSource;
RenderProductGridviews(theVariants);
prodView.SetActiveView(prodView.Views[0]);
}
packageForm.DataBind();
variantRepeat.DataBind();
Page.DataBind();
}
}
protected void RenderProductGridviews(System.Data.Objects.DataClasses.EntityCollection<Variant> variantCol)
{
foreach (Variant packVar in variantCol)
{
View newView = new View();
GridView prodGrid = new GridView();
var myProdDataSource = new List<vw_VariantProduct>();
using (var context = new GaleEntities())
{
var singleProd1 = context.vw_VariantProduct.Where(vp => vp.variantID == packVar.variantID);
foreach (vw_VariantProduct extProd in singleProd1)
{
myProdDataSource.Add(extProd);
}
}
prodGrid.DataSource = myProdDataSource;
BoundField _column = new BoundField();
_column.DataField = "product_title";
_column.HeaderText = "Product";
prodGrid.Columns.Add(_column);
_column = new BoundField();
_column.DataField = "product_title";
_column.HeaderText = "Product";
prodGrid.Columns.Add(_column);
_column = new BoundField();
_column.DataField = "product_desc";
_column.HeaderText = "Description";
prodGrid.Columns.Add(_column);
_column = new BoundField();
_column.DataField = "product_time";
_column.HeaderText = "Time (mins)";
prodGrid.Columns.Add(_column);
_column = new BoundField();
_column.DataField = "quantity";
_column.HeaderText = "Quantity";
prodGrid.Columns.Add(_column);
prodGrid.DataBind();
newView.ID = packVar.variantID.ToString();
newView.Controls.Add(prodGrid);
prodView.Views.Add(newView);
}
}

Now, as usual almost all questions with the dynamic controls in ASP.Net words share the same common problem...
You need to create the dynamic controls on every post, you are only creating them the first time the page is loaded. Follow this simple rules:
Dynamic controls should be created in the PreInit event when you are not working with a master page, if you are, then create the controls in the Init event
Avoid setting properties that can be changed in each post in these events because when the view state is applied (in a post event) the properties will be overridden
Dynamic controls must be created every time the page is posted, avoid this if(!this.IsPostBack) this.CreatemyDynamicControls();
When you create the controls in the PreInit or Init events, their states will be automatically set in a post event, which means in the LoadComplete event your controls will contain their state back even when you create them again in each post and even when you did not explicitly set their state. Note this behavior is different when you are dealing with controls created at design time, in that case, the event where the state has been set is the Load event
Event subscription should occur before the PageLoadComplete or they will not be raised
I have posted several answers about dynamic controls:
https://stackoverflow.com/a/11127064/1268570
https://stackoverflow.com/a/11167765/1268570
Click events on Array of buttons
Button array disappears after click event
Dynamically create an ImageButton
This piece of code creates dynamic controls on-demand, and each control keeps its state on each post
public partial class DynamicControlsOnDemand : System.Web.UI.Page
{
public int NumberOfControls
{
get
{
if (this.ViewState["d"] == null)
{
return 0;
}
return int.Parse(this.ViewState["d"].ToString());
}
set
{
this.ViewState["d"] = value;
}
}
protected void Page_PreLoad(object sender, EventArgs e)
{
this.CreateDynamicControls();
}
protected void addControl_Click(object sender, EventArgs e)
{
this.NumberOfControls = this.NumberOfControls + 1;
this.myPanel.Controls.Add(this.CreateTextbox(this.NumberOfControls));
}
private void CreateDynamicControls()
{
for (int i = 0; i < this.NumberOfControls; i++)
{
var t = this.CreateTextbox(i + 1);
t.TextChanged += (x, y) => this.lblMessage.Text += "<br/>" + (x as TextBox).ID + " " + (x as TextBox).Text;
this.myPanel.Controls.Add(t);
}
}
private TextBox CreateTextbox(int index)
{
var t = new TextBox { ID = "myTextbox" + index.ToString(), Text = "de" };
return t;
}
}
ASPX
<asp:Panel runat="server" ID="myPanel">
</asp:Panel>
<asp:Button Text="Add Control" runat="server" ID="addControl" OnClick="addControl_Click" />
<asp:Label ID="lblMessage" runat="server" />
Output

You first code block where you are setting the active View is based on an ItemCommand event, so I'm assuming this fires during a PostBack?
Your code which adds the additional views within Page_Load is only running if not a post back. Try removing the conditional if(!Page.IsPostBack) statement. You need to add dynamic controls on every page lifecycle.

Update DataGrid inside AJAX accordion

I have an AJAX accordion from the ajax control toolkit on a page with a datagrid inside on of the panels. I have a custom itemtemplate for the one column to create a multiline textbox when I click edit on the row. When I click update on the row, the original content of the textbox gets rendered into the textbox. It is supposed to update and go back to the literal not the textbox. When I put the DataBind() into a !IsPostBack, it doesnt get rendered when I click on the accordion pane. Any ideas?
Code:
protected void Page_Load(object sender, EventArgs e)
{
announ.HeaderStyle.CssClass = "header";
announ.Width = Unit.Percentage(100);
announ.GridLines = GridLines.None;
announ.AutoGenerateColumns = false;
announ.CellPadding = 10;
announ.CellSpacing = 0;
announ.HorizontalAlign = HorizontalAlign.Center;
announ.HeaderStyle.Font.Bold = true;
announ.EnableViewState = false;
announ.AlternatingItemStyle.BackColor = System.Drawing.Color.GhostWhite;
//announ.DeleteCommand += AnnounDeleteCommand;
announ.EditCommand += announ_EditCommand;
announ.UpdateCommand += announ_UpdateCommand;
announ.CancelCommand += announ_CancelCommand;
announ.DataKeyField = "id";
var tc1 = new TemplateColumn
{
HeaderTemplate = new
DataGridTemplate(ListItemType.Header, "Announcement"),
ItemTemplate = new DataGridTemplate(ListItemType.Item, "announcement_text"),
EditItemTemplate = new
DataGridTemplate(ListItemType.EditItem, "announcement_text")
};
var editColumn = new EditCommandColumn
{
ButtonType = ButtonColumnType.PushButton,
HeaderText = "Edit",
EditText = "Edit",
UpdateText = "Update",
CancelText = "Cancel"
};
var dateColumn = new BoundColumn {HeaderText = "Posted On", DataField = "date", ReadOnly = true};
var expirationColumn = new BoundColumn {HeaderText = "Expiration Date", DataField = "expiration_date"};
announ.Columns.Add(tc1);
announ.Columns.Add(dateColumn);
announ.Columns.Add(expirationColumn);
announ.DataSource = myAnnouncements;
announ.DataBind();
var deptMgtaccord = new Accordion
{
ID = "deptMgtaccord",
HeaderCssClass = "accordion-header",
HeaderSelectedCssClass = "accordion-headerSelected",
AutoSize = AutoSize.None,
SelectedIndex = 0,
FadeTransitions = true,
TransitionDuration = 250,
FramesPerSecond = 40,
RequireOpenedPane = false,
SuppressHeaderPostbacks = true
};
if (IsPostBack)
{
deptMgtaccord.SelectedIndex = selected;
}
var announcementPane = new AccordionPane {ID = "announcementPane"};
announcementPane.HeaderContainer.Attributes.Add("onmouseover", "this.style.backgroundColor='#e3e2e2';");
announcementPane.HeaderContainer.Attributes.Add("onmouseout", "this.style.backgroundColor='#ffffff';");
announcementPane.HeaderContainer.Controls.Add(new LiteralControl("Announcements >>"));
announcementPane.ContentContainer.Controls.Add(announ);
deptMgtaccord.Panes.Add(announcementPane);
var statsPane = new AccordionPane {ID = "statsPane"};
statsPane.HeaderContainer.Attributes.Add("onmouseover", "this.style.backgroundColor='#e3e2e2';");
statsPane.HeaderContainer.Attributes.Add("onmouseout", "this.style.backgroundColor='#ffffff';");
statsPane.HeaderContainer.Controls.Add(new LiteralControl("Statistics >>"));
statsPane.ContentContainer.Controls.Add(new LiteralControl("Stats"));
deptMgtaccord.Panes.Add(statsPane);
ph1.Controls.Add(deptMgtaccord);
}
protected void announ_CancelCommand(object source, DataGridCommandEventArgs e)
{
announ.EditItemIndex = -1;
announ.DataBind();
}
protected void announ_UpdateCommand(object source, DataGridCommandEventArgs e)
{
var dc = new MTCDataDataContext();
var announText = (TextBox) e.Item.Cells[1].Controls[1];
int announId = (int)announ.DataKeys[e.Item.ItemIndex];
var currentAnnoun = (from a in dc.announcements
where a.id == announId
select a).SingleOrDefault();
currentAnnoun.announcement_text = announText.Text;
dc.SubmitChanges();
announ.EditItemIndex = -1;
announ.DataBind();
}
protected void announ_EditCommand(object source, DataGridCommandEventArgs e)
{
announ.EditItemIndex = e.Item.ItemIndex;
announ.DataBind();
}
public class DataGridTemplate : ITemplate
{
ListItemType templateType;
string columnName;
public DataGridTemplate(ListItemType type, string colname)
{
templateType = type;
columnName = colname;
}
public void InstantiateIn(Control container)
{
Literal lc = new Literal();
TextBox tb = new TextBox();
switch (templateType)
{
case ListItemType.Header:
lc.Text = "<B>" + columnName + "</B>";
container.Controls.Add(lc);
break;
case ListItemType.Item:
lc.DataBinding += lc_DataBinding;
container.Controls.Add(lc);
break;
case ListItemType.EditItem:
tb.TextMode = TextBoxMode.MultiLine;
tb.Rows = 6;
tb.Columns = 57;
tb.DataBinding += tb_DataBinding;
container.Controls.Add(tb);
break;
case ListItemType.Footer:
lc.Text = "<I>" + columnName + "</I>";
container.Controls.Add(lc);
break;
}
}
void tb_DataBinding(object sender, EventArgs e)
{
TextBox tb = (TextBox)sender;
DataGridItem row = (DataGridItem)tb.NamingContainer;
tb.ID = "txt_" + row.ItemIndex;
tb.Text = DataBinder.Eval(row.DataItem, columnName).ToString();
}
void lc_DataBinding(object sender, EventArgs e)
{
Literal lc = (Literal)sender;
DataGridItem row = (DataGridItem)lc.NamingContainer;
lc.ID = "txt_" + row.ItemIndex;
lc.Text = DataBinder.Eval(row.DataItem, columnName).ToString();
}
}

You need to add your dynamic controls in PreInit on every request in order for the controls to get back into the ControlTree and raise events.
Page Event:
PreInit
Typical Use:
Raised after the start stage is complete and before the initialization stage begins.
Use this event for the following:
Check the IsPostBack property to determine whether this is the first
time the page is being processed. The
IsCallback and IsCrossPagePostBack
properties have also been set at this
time.
Create or re-create dynamic controls.
Set a master page dynamically.
Set the Theme property dynamically.
Read or set profile property values.
Note: If the request is a postback, the values of the controls have not yet been restored from view state. If you set a control property at this stage, its value might be overwritten in the next event.