Autopostback is working only for the first time in ASP.NET?

Question

Here i am using a radio button to calculate the date difference between two textboxes and i am showing it in another textbox.It is working only for the first time when i click the radio button after that it is not working..Here is my code

<asp:RadioButton ID="rdoSpecifiedDates"  runat="server" class="bodycontent"   GroupName="status"/>
<asp:RadioButton ID="rdoDateRange" runat="server" class="bodycontent" 
GroupName="status"  oncheckedchanged="rdoDateRange_CheckedChanged" AutoPostBack="true"
/>

 <asp:UpdatePanel ID="Update" runat="server">
 <ContentTemplate>
 <asp:TextBox ID="txtDays" runat="server" CssClass="bodycontent" MaxLength="6" ReadOnly="true"></asp:TextBox>
 </ContentTemplate>
 <Triggers>
 <asp:AsyncPostBackTrigger ControlID="rdoDateRange" />
 </Triggers>
 </asp:UpdatePanel>

and

protected void rdoDateRange_CheckedChanged(object sender, EventArgs e)
        {
            DateTime startdate=Convert.ToDateTime(txtOStartDate.Text);
            DateTime enddate=Convert.ToDateTime(txtOEndDate.Text);
            var result = (enddate - startdate).TotalDays;
            txtDays.Text =Convert.ToString( result);
        }

Any suggestion?

Is not working means it does not postback at all on CheckedChanged? Have you debugged with a breakpoint in Page_Load and in your CheckedChanged-handler? — Tim Schmelter, Mar 29 '12 at 08:17
When this happens, you usually have an error on post back, maybe you do not populate correct all the controls. Remove the update panel and make the same actions and probably you find it. — Aristos, Mar 29 '12 at 08:24

Tami · Accepted Answer · 2012-03-29T13:22:57.853

its happening because you are forcing only post back on rdoDateRange...and when the other rdoSpecifiedDates is clicked no postback occur so that's why you rdoDateRange dose not reflect any change..

So make the rdoSpecifiedDates AutoPostBack = true.

hmm...either you have to put both rdobuttons in your trigger.. like this

   <asp:RadioButton ID="rdoSpecifiedDates" runat="server" AutoPostBack="true" class="bodycontent" GroupName="status" />
        <asp:RadioButton ID="rdoDateRange" runat="server" class="bodycontent" GroupName="status"
            OnCheckedChanged="rdoDateRange_CheckedChanged" AutoPostBack="true" />
        <asp:UpdatePanel ID="Update" runat="server">
            <ContentTemplate>
                <asp:TextBox ID="txtDays" runat="server" CssClass="bodycontent" MaxLength="6" ReadOnly="true"></asp:TextBox>
            </ContentTemplate>
            <Triggers>
                <asp:AsyncPostBackTrigger ControlID="rdoDateRange" />
                <asp:AsyncPostBackTrigger ControlID="rdoSpecifiedDates" />
            </Triggers>
        </asp:UpdatePanel>

OR

Put both the radio buttons in update pannel like this..

<asp:UpdatePanel ID="Update" runat="server">
            <ContentTemplate>
                <asp:RadioButton ID="rdoSpecifiedDates" runat="server" AutoPostBack="true" class="bodycontent"
                    GroupName="status" />
                <asp:RadioButton ID="rdoDateRange" runat="server" class="bodycontent" GroupName="status"
                    OnCheckedChanged="rdoDateRange_CheckedChanged" AutoPostBack="true" />
                <asp:TextBox ID="txtDays" runat="server" CssClass="bodycontent" MaxLength="6" ReadOnly="true"></asp:TextBox>
            </ContentTemplate>
            <Triggers>
                <asp:AsyncPostBackTrigger ControlID="rdoDateRange" />                
            </Triggers>
        </asp:UpdatePanel>

gave it like that it is not working..Second time when i click that radio button it is not even going to the rdoDateRange_CheckedChanged event. — bala3569, Mar 29 '12 at 11:57

Gabriel Scavassa · Answer 2 · 2012-03-29T12:58:55.120

You Also can do..:

<div>

   <asp:RadioButton ID="rdoSpecifiedDates" runat="server" class="bodycontent" 
    GroupName="status" oncheckedchanged="rdoSpecifiedDates_CheckedChanged" AutoPostBack="true" />
    <asp:RadioButton ID="rdoDateRange" runat="server" class="bodycontent" GroupName="status"
        OnCheckedChanged="rdoDateRange_CheckedChanged" AutoPostBack="true" />

 <asp:ScriptManager ID="ScriptManager1" runat="server" />   
    <asp:UpdatePanel ID="Update1" runat="server" UpdateMode="Conditional" >

            <ContentTemplate>
                <asp:TextBox ID="txtDays" runat="server" CssClass="bodycontent" MaxLength="6" Enable="False"></asp:TextBox>
            </ContentTemplate>
        </asp:UpdatePanel>

    </div>

And

protected void rdoDateRange_CheckedChanged(object sender, EventArgs e)
        {
            DateTime startdate = DateTime.Now.AddHours(2);
            DateTime enddate = DateTime.Now.AddHours(5);
            TimeSpan  result = enddate - startdate;
            txtDays.Text = result.ToString();
            Update1.Update();
        }
 protected void rdoSpecifiedDates_CheckedChanged(object sender, EventArgs e)
        {

        }

@bala3569 When you just click in the second rarioButton it updates. — Gabriel Scavassa, Mar 29 '12 at 12:20
@bala3569 by the way the 'ID="rdoSpecifiedDates"' needs a autopostback too, and maybe a 'OnCheckedChanged="rdoDateRange_CheckedChanged"' even empyt try and let me know!! — Gabriel Scavassa, Mar 29 '12 at 12:57

score 1 · Answer 3 · answered Feb 19 '15 at 06:34

If your radio buttons are outside of the update panel (and need to be so), the selected/checked item will never fire due to not having any JavaScript on its <input> tag, which is logical in the sense that the page thinks the element is already selected so why would it need to fire off back to the server when it is clicked?

But it obviously causes issues in this scenario because, as triggers for an update panel, it never "repaints" itself to reflect that the selected item has changed.

My workaround for this is to "repaint" the radio buttons as well by having them in their own <asp:UpdatePanel> control:

<asp:UpdatePanel ID="RadioButtonUpdate" runat="server">
    <ContentTemplate>
        <asp:RadioButton ID="rdoSpecifiedDates"  runat="server" class="bodycontent"
            GroupName="status" OnCheckedChanged="rdoSpecifiedDates_CheckedChanged" AutoPostBack="true" />
        <asp:RadioButton ID="rdoDateRange" runat="server" class="bodycontent" 
            GroupName="status"  OnCheckedChanged="rdoDateRange_CheckedChanged" AutoPostBack="true" />
    </ContentTemplate>
</asp:UpdatePanel>

<asp:UpdatePanel ID="Update" runat="server">
    <ContentTemplate>
        <asp:TextBox ID="txtDays" runat="server" CssClass="bodycontent" MaxLength="6" ReadOnly="true"></asp:TextBox>
    </ContentTemplate>
    <Triggers>
        <asp:AsyncPostBackTrigger ControlID="rdoDateRange" />
    </Triggers>
</asp:UpdatePanel>

This feels to me like the cleanest solution outside of housing the radio buttons within the update panel you are wanting refreshed.

Autopostback is working only for the first time in ASP.NET?

3 Answers3