Getting wrong values from dynamically created check box

Question

I am trying to read from a dynamically created checkbox on button click. The problem is that once the checkbox is checked, further uncheck operation are not read properly on submit click.

EDIT: The checkbox is initially created on the selection of a radiobuttonlist by calling SetSelection as shown.

The code snippet is shown below, Any idea what could be the possible problem?

protected void Page_Load(object sender, EventArgs e)
{    
    if (this.IsPostBack)
    {
    ..
        GenerateDynamicUI();
    }
    ...
}     


private void GenerateDynamicUI(int selectedItem)
{
    ...
    TableCell cellCheckBox = new TableCell();
    CheckBox chkBox = new CheckBox();              
    chkBox.Text = "Consider all";
    chkBox.ID = "chkAll";
    cellCheckBox.Controls.Add(chkBox);

    TableRow chkRow = new TableRow();
    chkRow.Cells.Add(cellCheckBox);
    table.Rows.Add(chkRow);
}

protected void btnSubmit_Click(object sender, EventArgs e)
{
    ...
    bool isChecked = ((CheckBox)table.FindControl("chkAll")).Checked;   

}

private void SetSelection()
{
    int selectedItem = int.Parse(radiobuttonList.SelectedItem.Value);           
    GenerateDynamicUI(selectedItem);
    pnlDynamic.Visible = true;            
}

protected void radiobuttonList_SelectedIndexChanged(object sender, EventArgs e)
{
     SetSelection();
}

Does this CheckBox already present in your webform code or it will just created on Postback? — Fraz Sundal, Jan 15 '12 at 17:04
I cant find any issue in this code its giving me correct value of checkbox each time. Can you elaborate your problematic scenario? — Fraz Sundal, Jan 15 '12 at 17:22
I second that, also is this the entire declaration of the CheckBox and its containing Controls? I'm wondering if the CheckBox is being modified at some stage? — Brissles, Jan 15 '12 at 17:38
Please see edited code. I am having a radiobutton list. Based on the selection, I am creating the checkbox dynamically using `SetSelection` method. SCENARIO: When the checkbox is not checked and when I do a submit, isChecked is giving false and when I check it and do submit, it is returning true (as expected). But when I uncheck it again, still it is returning true. — softwarematter, Jan 15 '12 at 17:47
Are you calling GenerateDynamicUI from Page_Load AND from your RadioButtonList SelectedIndexChanged? — Brissles, Jan 15 '12 at 18:08

Brissles · Answer 1 · 2012-01-16T01:10:29.970

4

I've recreated your example and it works fine. I can only imagine there's something else in your code responsible for the unexpected behaviour.

Try using the Page_PreInit event rather than Page_Load to re-create/manipulate your dynamic controls:

protected void Page_PreInit(object sender, EventArgs e)
{
    // create controls here
    GenerateDynamicUI();
}

More info: http://msdn.microsoft.com/en-us/library/ms178472.aspx

By 'not ready properly' I assume you mean it stays True and never returns False after the first time you've check it?

edited Jan 16 '12 at 01:10

answered Jan 15 '12 at 17:20

Brissles

3,833
23
31

Yes, it stays True and never returns False after the first time I check it. – softwarematter Jan 15 '12 at 17:28
+1 for building dynamic controls in PreInit. That's where they belong – Bryan Crosby Jan 15 '12 at 18:13

score 2 · Answer 2 · answered Jan 15 '12 at 17:00

2

it looks like you declaring

bool isChecked = ((CheckBox)table.FindControl("chkAll")).Checked;

in the btnSubmit if so it would be reset to false every time the method is called. try declaring it out side. IE:

bool isChecked;
protected void btnSubmit_Click(object sender, EventArgs e)
{
    ...
    isChecked = ((CheckBox)table.FindControl("chkAll")).Checked;   

}

answered Jan 15 '12 at 17:00

Dusty

413
6
17

This won't matter, it's a local var. Furthermore it's written to each time. – Brissles Jan 15 '12 at 17:02

Getting wrong values from dynamically created check box

2 Answers2