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Double pass required for TextBox Postback in FormView

This is a follow up to an earlier issue which I provided my own answer to but there is a new wrinkle in the process that I'm looking for an answer.
Scenario:
Have a asp.TextBox embedded inside of a asp.FormView control. Prior issue was that I couldn't populate the TextBox from code behind (C#). This was corrected by adding AutoPostBack = "true" to the TextBox.
Issue:
The postback corrected the population of the Text box but now two passes on the control assignment have to be executed in order to see the textbox populated.
Specific Question
How can correct this so it doesn't require a second click of the button to see the textbox populated.
Code Examples:
/*-- This is the fragment of code in the aspx which is related to the issue: --*/
<asp:FormView runat="server" ID="EditImpStndPreamble" DataSourceID="ImpStndPreambDS" OnItemCommand="EditImpStndPreamble_ItemCommand" DefaultMode="Edit" DataKeyNames="ARS_Index">
<InsertItemTemplate>
<asp:Label runat="server" Font-Size="Small" Font-Bold="true" Width="60" Text="Index #"></asp:Label>
<asp:Label Text='<%# Eval("ARSEL_Index") %>' runat="server" ID="ARSEL_IndexLabel1" Width="74" />
<asp:Label runat="server" Width="60" Font-Size="Small" Font-Bold="true" Text="Control #"></asp:Label>
<asp:TextBox Text='<%# Bind("ARSControlNum") %>' runat="server" ID="ARSControlNumTextBox" Width="74" />
<asp:LinkButton runat="server" Text="Insert" CommandName="Insert" ID="InsertButton" CausesValidation="True" /> <asp:LinkButton runat="server" Text="Cancel" CommandName="Cancel" ID="InsertCancelButton" CausesValidation="False" />
</InsertItemTemplate>
</asp:FormView>
// This is the fragmentof code in the C# code behind related to the issue
// This is where we update the control number
Label ctrnum = (Label)EditElementsFV.Row.FindControl("ARSControlNumLabel");
if (ctrnum != null)
ctrnum.Text = Session["CurrentControl"].ToString();
Any insight here would be welcomed. I've tried several things but haven't come up with a means of making this work like I want it to. I'm thinking if I could trigger a second postback of only the TextBox control here that could resolve it. The problem is every method of doing a postback from code behind seems to reset the page which by default has this FormView invisible.
Regards,
Updated 03/24/17 1:06PM Central US:
I took a bit of a break from this issue to work on another segment of the project. I tried several more thing but the last thing I did was track several variables through the debugger and examine the flow of the code as I stepped through the pertinent sections of code.
To the double tap issue I discovered that the first time you click on the Insert Implementation Standards button that the execution was routed through 'Item Template' of the FormView and then it ran through the 'Insert Template' before coming to rest.
Conversely the second click of the button executed as I would have expected and ONLY executed the 'Insert Template of the FormView.
I also observed all the variables that are used in the DataSource related to the FormView being properly populated prior to the execuation of either the Item Template and/or the Insert Template of the FormView.
So, this is even more baffling that I originally ran into it because at first all that I was dealing with was the lack of visibility of two TextBoxes, now however, we have the curiosity of the code executing the Item Template of the FormView prior to walking through the Insert Template.
Ken...
Updated: 03/27/17 9:55AM Central US
I have been working on this and searching for examples of similar issues that I might be able to leverage from and so have now attempted using a FormView.ItemInserting block (Which is bypassed prior to actual execution of the 'insert') and FormView.DataBound blocks. The DataBound was able to trigger but I had to encompass the block in a conditional 'if (IsPostBack)' to avoid trigging a null reference error. This properly routed through the block however the result on the screen draw was the same wit the fields not being populated as intended. Here is the last block as last attempted:
protected void EditElementsFV_DataBound(object sender, EventArgs e)
{
if (IsPostBack)
{
Label ctrnum = (Label)EditImpStndPreamble.Row.FindControl("ARSControlNumLabel");
if (ctrnum != null)
ctrnum.Text = Session["CurrentControl"].ToString();
Label famlbl = (Label)EditImpStndPreamble.Row.FindControl("ColumnTagLabel");
if (famlbl != null)
famlbl.Text = Session["CurrentFamily"].ToString();
}
}
Pressing on but could really use some other eyes on this.
Update: 03/29/17 7:42AM Central US
I wanted to post this update yesterday but got pulled off on a different project for a bit. My latest attempt to resolve this issue I thought for certain that it would work. But it has also failed to load the values into the insert mode of the forum until the button has been selected the second time.
What this does is from the trigger of 'DataBound' in the FormView it directes the flow to a function FillDefaultValue which assigns default values to the two parameters that are in the FormView that control the TextBox displays.
In my mind this 'should have' resolved the issue as the default value would then be the values contained in the Session variables instead of being blank(null).
public void FillDefaultValueInFormView()
{
if (EditElementsFV.CurrentMode == FormViewMode.Insert)
{
EditElementsDS.SelectParameters["ARSControlNum"].DefaultValue = Session["CurrentControl"].ToString();
EditElementsDS.SelectParameters["ColumnTag"].DefaultValue = Session["CurrentColumn"].ToString();
}
}
protected void EditElementsFV_DataBound(object sender, EventArgs e)
{
if (IsPostBack)
{
FillDefaultValueInFormView();
}
}
So the mystery continues...

I ended up using the function FillDefaultValueInFormView() defined in the question to resolve this.
I watch in debut the flow over and over again and realized what was happening was that when I set the FormView's mode to Insert that it was flushing the value assignments that I was placing on the TextBox.
Then I realized that what I needed to do was assign the default value in the DataSource to be what I desired in the TextBox 'prior' to setting the mode of the FormVeiw to Insert. So, I added the call to the function in the early portion of my Button_click event immediately followed by changing mode of the FormView to Insert.
protected void AddImpStadBTN_Click(object sender, EventArgs e)
{
Session["CurrentColumn"] = "IMP";
FillDefaultValueInFormView();
EditElementsFV.ChangeMode(FormViewMode.Insert);
... More code follows to complete this but left off as it doesn't effect the results...
}
After doing this the change to insert mode on the FormView was successfully prepopulated as I had intended for the user. I'll now change them to ReadOnly so the user can't change them, making them programmatically driven fields within the form.

UpdatePanel.Update() command generates a full Page_load

I have a Update Panel inside a User Control i use on 2 pages in my website
Both pages use the same MasterPage, ScriptManger is declared in the MasterPage.
Both pages call the UC the same way:
<uc:SearchCube runat="server" ID="searchCube" />
in the Update panel i have many RadioButtons that on change generate a server side event that fill dropdown in the update panel and update the panel
protected void SearchCategoryChanged(object sender, EventArgs e)
{
FillDropdowns();
SearchOptions.Update();
}
Update Panel is set like this:
<asp:UpdatePanel ID="SearchOptions" runat="server" UpdateMode="Conditional"
hildrenAsTriggers="true"/>
Each RadioButton is set like this:
<asp:RadioButton ID="RadioButton1" GroupName="SearchCategory" runat="server"
AutoPostBack="true" OnCheckedChanged="SearchCategoryChanged" Text="Text"/>
I also have an AsyncPostBackTrigger on each Radio Button Controller
The problem i have is that on one page when i call the Update() function the panel is updated and Page_Load is triggered which causes the UC to refresh and reload the default settings of the UC
I can see in DEBUG mode that on the working page Update() does not generate Page_Load.
Can anyone explain to me why this is happening?

Everytime a request goes to the server, it executes the Page_Load event.
What you need to do is make sure you have a PostBack validation on all your pages:
protectec void Page_Load(object sender, EventArgs e)
{
if(!Page.IsPostBack)
{
//Not a postBack: Normal page load
//Init your page here
}
else
{
//It's a PostBack (from a command).
//Do nothing or init stuff your all your commands.
}
}
If you put some breakpoints in your Page Load and your SearchCategoryChanged method, you'll be able to see what the pipeline looks like.

Fixed my problem.
the problematic page is an index page that takes a few parameters in.
I have a Response.Redirect() on the page to avoid duplication of pages.
Apparently when the PostBack() is made it calls the page without any parameters and i was forcing it to be redirected into a default view since no parameters were sent to the page.
i found a lead to my problem in a Microsoft help forum that stated:
By calling Response.Write() directly you are bypassing the normal
rendering mechanism of ASP.NET controls. The bits you write are going
straight out to the client without further processing (well,
mostly...). This means that UpdatePanel can't encode the data in its
special format.
Anyway the page was reloading every time which caused it to reload the User Control with it's default values.

Why is ASP.NET submitting the original value of a TextBox control when the contents have been changed?

I have a web form that allows the user to modify data in certain fields (mostly TextBox controls, with a couple of CheckBox, DropDownList, and one RadioButtonList control) with a submit button to save the changes. Pretty standard stuff. The catch is, I need to keep track of which fields they modified. So I'm using ASP.NET HiddenField controls to store the original value and then on submit comparing that to the value of the corresponding TextBox (for example) control to determine which fields have been modified.
However, when I submit the form and do the comparison, the value of the TextBox control in the code behind still reflects the original value, even though I have changed the contents of the TextBox, so it isn't registering the change. Here is an example of a set of TextBox/HiddenField pairings (in this case last, first, middle names) in my ASP.NET form:
<div id="editName" class="editField" style="display: none">
<asp:TextBox ID="tbxLName" runat="server" class="editable"></asp:TextBox>,
<asp:TextBox ID="tbxFName" runat="server" class="editable"></asp:TextBox>
<asp:TextBox ID="tbxMName" runat="server" class="editable"></asp:TextBox>
<asp:HiddenField ID="hdnLName" runat="server" />
<asp:HiddenField ID="hdnFName" runat="server" />
<asp:HiddenField ID="hdnMName" runat="server" />
</div>
I'm setting the original values of all these controls (".Text" for the TextBox controls, ".Value" for the HiddenField controls) on PageLoad in the code behind.
Here's an example of where I'm doing the comparison when I submit the form (I'm adding the field name, old value, and new value to List<string> objects if the values differ):
if (tbxLName.Text != hdnLName.Value)
{
changes.Add("ConsumerLastName");
oldVal.Add(hdnLName.Value);
newVal.Add(tbxLName.Text);
}
But when I enter a new value into the TextBox control and click Submit:
then step through the code in the debugger, it shows me that the value of the control is still the old value:
Why is the comparison happening against the original value of the TextBox even though the new value is there when I click the submit button?
Update: #David gets the credit for this, even though he didn't post it as an answer -- I was forgetting to enclose the method for pre-filling the original values of the controls in a check for IsPostBack; I really should have known better, I've been doing this for quite a while!

Are you checking for IsPostback in Page_Load so you don't overwrite the values sent in the Postback?

Make sure that you are not overwriting your values in the Page_Load method:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
someTextField = "Some Value";
}
}
It took a while for me to get that the Page_Load method works as an "before anything goes" method and not only a method that is being ran when you visit the page with GET.

Make sure you're not overwriting the value for the textbox somewhere in page init or load without checking for the IsPostback flag.

It may happen due to postback. If you code for set textbox not in !isPostBack then put it.
i.e.
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
tbxLName.Text="anything";
}
}

Adding a control to a list of Controls dynamically

I have a web page where users need to enter customer contact information. They could enter from 0 to an infinite number of contacts.
I created this page code on page:
<ajaxToolkit:ToolkitScriptManager runat="Server" EnablePartialRendering="true" ID="ScriptManager1" />
<asp:PlaceHolder ID="phCustomerContacts" runat="server" EnableViewState="true">/asp:PlaceHolder>
<asp:LinkButton ID="btnAddContact" runat="server" OnClick="btnAddContact_Click" CssClass="LinkButton" Text="Add Contact"/>
In my code behind I added this:
public void btnAddContact_Click(object sender, EventArgs e)
{
IList<CustomerContactProfile> customerContacts = new List<CustomerContactProfile>();
if (ViewState["CustomerContactList"] != null)
customerContacts = (List<CustomerContactProfile>)ViewState["CustomerContactList"];
CustomerContactProfile contactProfile = (CustomerContactProfile)LoadControl("~/Controls/Embedded/CustomerContactProfile.ascx");
customerContacts.Add(contactProfile);
foreach (CustomerContactProfile contact in customerContacts)
phCustomerContacts.Controls.Add(contact);
ViewState["CustomerContactList"] = customerContacts;
}
This code doesn't work because the ViewState can't handle storing all of that control data. However, I cannot think of another way to store the controls that were already added.
The viewstate of the asp:PlaceHolder control doesn't save anything and I need the controls to be saved so that if a user puts in some data to the first control that the data isn't lost when they add a second one and so on.

Rather than store the entire control, simply store the underlying data in session, and rebuild the control set from that data every time you reload the page.

I'm not sure it's a best way to add contacts dynamically. Wouldn't it be better to create controls via jquery, and send data for creation to web method ?

It would be better to store the number of controls in viewstate to add instead... And then add them in Page Init or PreInit... ViewState would then be retained for each of the dynamic controls. This would be for postbacks after the button click of course.
HTH.

Store the number of controls the user has entered in the view state. Override the LoadViewState page method and add back the number of controls there. The framework will take care of reloading the posted data into the controls for you. You will not lose information. You just have to make sure you add the controls BEFORE the viewstate is restored.

Store it in the Session instead of Viewstate. It's just as bad but it will work!

I think you should not depend on any temporary storage for this -- Viewstate, Session, or otherwise.
You seem to be using your .ascx like I would normally use a class... User control's going to be bigger, though, I imagine, since it has lots of html in it (?).
Anyway, a generic list of a class would be...smaller, at least.
But otherwise, my favorite approach is just to insert each record into a database when it's done (one-by-one) -- at least for manual input, which that's my impression of what you're working with. For example, using a listview, detailsview, gridview, etc.

UpdatePanel reloads the whole page

I'm building an asp.net cutom control inside which I have two dropdownlists: companyIdSelection and productFamilySelection.I populate the companyIdSelection at Page_Load and in order to populate the productFamilySelection depending on the selected item in companyIdSelection.I'm using UpdatePanels to achieve this, but for some reason every time I update companyIdSelection Page_Load is being called ( which as far as I know should happen only when the entire page is reloaded ), the list is being reloaded again and the item the user selected is lost( the selected item is always the top one ).Here's the code
<asp:UpdatePanel ID="updateFamilies"
runat="server"
UpdateMode="Always">
<ContentTemplate>
Company ID:<br>
<br></br>
<asp:DropDownList ID="companyIdSelection"
runat="server"
AutoPostBack="True"
OnSelectedIndexChanged="companyIdSelection_SelectedIndexChanged">
</asp:DropDownList>
<br></br>
Product Family:
<br></br>
<asp:DropDownList ID="productFamilySelection" runat="server"
AutoPostBack="True"
onselectedindexchanged="productFamilySelection_SelectedIndexChanged">
</asp:DropDownList>
<br>
</ContentTemplate>
</asp:UpdatePanel>
protected void Page_Load(object sender, EventArgs e)
{
this.companyIdSelection.DataSource = companyIds(); //companyIds returns the object containing the initial data items
this.companyIdSelection.DataBind();
}
protected void companyIdSelection_SelectedIndexChanged(object sender, EventArgs e)
{
// Page_Load is called again for some reason before this method is called, so it
// resets the companyIdSelection
EngDbService s = new EngDbService();
productFamilySelection.DataSource = s.getProductFamilies(companyIdSelection.Text);
productFamilySelection.DataBind();
}
Also, I tried setting the UpdateMode of the UpdatePanel to "Conditional" and adding an asyncpostback trigger
but the result was the same.
What am I doing wrong?
PS:
I fixed the updating problem, by using Page.IsPostBack in the Page_Load method, but I would still want to avoid a full postback if possible

I think you misunderstand how UpdatePanels work. They DO actually do a full page postback, it's just that during the rendering stage they capture only a portion of the output and send it back in the AJAX response so the page can be updated. More info here.
So you will still need to check whether it is a postback in your page_load event and only perform your data load if it isn't one.

The update panel call back will go through the page load on every call back. In face, the pull page lifecycle (minus render and prerender) will occur. Update panels give the appearance of ajax, but your client side code still posts back to the same page - which is the problem you are describing. If you can avoid using Update Panels, I suggest you do so. Use something like jQuery instead. If not, then use this in your Page_Load
if (Page.IsCallback) { } //Do callback specific code here
else { } //Do Postback specific code here
Hope this helps. Good Luck.