Update Panel and triggers from a repeater control

Question

Hi I found code similiar to the following online. It's seems really great for getting a button buried in a repeater control to trigger a full cycle back to the server.

<asp:ScriptManager ID="ScriptManager1" runat="server"> 
        </asp:ScriptManager> 

        <asp:UpdatePanel ID="UpdatePanel1" runat="server"> 
            <ContentTemplate> 
                <%=DateTime.Now.ToString() %> 
            </ContentTemplate> 
            <Triggers> 
                <asp:PostBackTrigger ControlID="HiddenButton" /> 
            </Triggers> 
        </asp:UpdatePanel> 

        <!--Make a hidden button to treat as the postback trigger--> 
        <asp:Button ID="HiddenButton" runat="server" Style="display: none" Text="HiddenButton" /> 


        <asp:Repeater ID="Repeater1" runat="server" DataSourceID="SqlDataSource1"> 
            <ItemTemplate> 
                 <!--when cick the button1, it will fire the hiddenButton--> 
                <asp:Button ID="Button1" Text="Trigger" CommandArgument='<%# Eval("Id") %>' OnClientClick="$get('HiddenButton').click();return false;" 
                    runat="server" /> 
            </ItemTemplate> 
        </asp:Repeater>

It uses a hiddenButton to achieve this by hooking the click event of the original button to this one. However my addition to this was the setting of the CommandArgument for the button. I would also need it to be set for the HiddenButton.

Does anyone know a way of going about this?

Answer 1

First I will like to explain the Disadvantage of using the Update Panel using the very same example posted by you.

Below is the Original Code

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Output

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To display the 22 character string you can check how much data is being received and sent to server. Just imagine following

1. If you would consider send each request to Database using Update Panel and your GridView is in Update Panel!!!!!!
2. Suppose you would use ViewState data for each request and with GridView Inside the Update Panel.

Both the above techniques are worst as per my understanding.

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Now I will describe you Page Methods

Page Method over Update panel

Page Methods allow ASP.NET AJAX pages to directly execute a Page’s Static Methods, using JSON (JavaScript Object Notation). Instead of posting back and then receiving HTML markup to completely replace our UpdatePanel’s contents, we can use a Web Method to request only the information that we’re interested.

Sample Code

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Output

Hope this clearly explains the difference of usage.

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Answer to the original Query

You have to register the ItemDataBound event of the below Repeater and use below code for it.

Code Behind

protected void Repeater1_ItemDataBound(object sender, RepeaterItemEventArgs e)
{
    if (e.Item.ItemType == ListItemType.Item || 
                           e.Item.ItemType == ListItemType.AlternatingItem)
    {
        Button btn = (Button)e.Item.FindControl("Button1");
        btn.OnClientClick = string.Format("SubmitButton('{0}');return false;"
                                                        , HiddenButton.ClientID);

    }
}

---

JavaScript

<script type="text/javascript">
     function SubmitButton(btn)
     {
         $("#" + btn).click(); 
     }
</script>

//Alternative

<script type="text/javascript">
     function SubmitButton(btn)
     {
         document.getElementById(btn).click(); 
     }
</script>

---

Reference & Here

Answer 2

Your HiddenButton control is a server control but you are trying to access it in JQuery using it's ASP.Net ID,

<asp:Button ID="Button1" Text="Trigger" CommandArgument='<%# Eval("Id") %>' OnClientClick="$get('**HiddenButton**').click();return false;" 
                runat="server" /> 

A quick way to fix it is to make a separate function,

<script type="text/javascript">
function SubmitButton(btn)
{
     $get("#" . btn).click(); 
}
</script>

and change your button code to ,

<asp:Button ID="Button1" Text="Trigger" CommandArgument='<%# Eval("Id") %>' 
                runat="server" /> 

In code behind, in repeater's ItemDataBound event, find the button and HiddenControl and set Button1's OnClientClick property,

Button1.OnClientClick= string.Format("SubmitButton('{0}');return false;",HiddenButton.ClientID);