Question

I have a problem with a webform.

My Goal: Intially when a page is loading, it has to load every textbox empty. After filling the info and click submit, it has to get submitted(UpdatePaymentInfo())

Problem: Here, When the user fills the info and clicks Submit,it calls onload function even before the submit button and makes all text box empty.

Here is the code:

protected override void OnLoad(EventArgs e)
{
    base.OnLoad(e);

    string QueryStringupdatecreditcard1 = Request.QueryString.ToString();

    if (String.Equals(QueryStringupdatecreditcard1, "tabID=B"))
    {
        divTitle.Visible = false;
        trmain.Visible = false;
        tdOrderSummary.Visible = false;
        trCCandBilling.Visible = true;
        trtest2.Visible = false;
        divUpdatecreditcard.Visible = true;
        trusecompaddress.Visible = false;

        txtFirstName.Text = "";
        txtLastName.Text = "";
        txtAddress1.Text = "";
        txtAddress2.Text = "";
        txtCity.Text = "";
        txtZip.Text = "";
        txtCardNo.Text = "";
        txtVccNumber.Text = "";
        trAmountCharged.Visible = false;
    }
}

protected void imgbtnSubmit_Click(object sender, ImageClickEventArgs e)
{
    try
    {
        UpdatePaymentInfo();
    }
}

Answer 1

Wrap the current contents of your OnLoad method in:

if (!Page.IsPostBack)
{
    // Code in here will only be executed when the page is *not* being loaded by a postback
}

This is because, as per the ASP.NET Page Life Cyle, the things that you care about in this instance happen in this order:

Load – During load, if the current request is a postback, control
properties are loaded with information
recovered from view state and control
state.

Postback event handling – If the request is a postback, control event
handlers are called. After that, the
Validate method of all validator
controls is called, which sets the
IsValid property of individual
validator controls and of the page.

So what happens is (somewhat simplified):

1. You click the image button, triggering the postback.
2. The data from your form is loaded into your controls.
3. Your OnLoad method overwrites the values in the controls to clear them.
4. Your click handler is run, but because of step 3 it sees empty values.

As others have sort-of mentioned, it wouldn’t necessarily be a bad thing to refactor your OnLoad method whilst you’re doing this. At the moment you seem to have it doing two distinct things:

• Clearing the text fields
• Setting the visibility of fields

It might be worth separating this into one or two (depending on if the visibility setting and field clearing will be done independently) separate methods and adjusting your OnLoad method so it looks like this:

protected override void OnLoad(EventArgs e)
{
    base.OnLoad(e);

    if (!Page.IsInPostBack)
    {
        SetFieldVisibility();
        ClearFields();
    }
}