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RadContextMenu

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Ajax

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13 Answers, 1 is accepted

answered on 21 Sep 2010, 08:09 PM

Items to be added to context menu....

<telerik:RadContextMenu ID="rcmContextMenu" iscontext="True" runat="server" Skin="Outlook"

OnItemClick="rcmContextMenu_ItemClick" contextmenuelementid="none">

<Items>

<telerik:RadMenuItem Text="Edit" />

<telerik:RadMenuItem Text="Delete" />

</Items>

</telerik:RadContextMenu>

I am modifying existing code to add a context menu and am trying to minimize the scope of changes. This is the only place where a context menu is required so I would prefer to keep this grid consistent with the other grids (all utilizing the asp:GridView control) in the application.

answered on 22 Sep 2010, 08:01 PM

For a RadGrid with the following settings;

</ClientSettings>

And a RadContextMenu is configured as shown;

telerik:RadContextMenu ID="rcmContextMenu" iscontext="True" runat="server" Skin="Outlook"

OnItemClick="rcmContextMenu_ItemClick" contextmenuelementid="none">

<Items>

<telerik:RadMenuItem Text="Edit" />

<telerik:RadMenuItem Text="Delete" />
</

Items>

telerik:RadContextMenu>

The following occurs when a RadContextMenu is used on the RadGrid;

1) Right click on selected grid row.
2) Context menu appears as expected
3) An item is selected off of the context menu
4) RadGrid_SelectedIndexChanged event is fired
5) RadContextMenu_ItemClick event is fired

How is it possible to use a RadContextMenu when RadGrid_SelectedIndexChanged fires when an item is selected off of the context menu before RadContextMenu_ItemClick fires?

answered on 28 Sep 2010, 01:32 PM

Hello Zeke,

We already answered to your colleague Creigh about the ContextMenu for RadGrid. I am forwarding the message from Veli Pehlivanov:

"You are getting RadGrid's server-side SelectedIndexChanged event fire, because a right click on a grid row selects the row. So, you are showing the context menu on right click, but the item you are showing the context menu for is also selected. When the page postbacks, any changes to the selected items that have been made on the client cause RadGrid to fire the SelectedIndexChanged event.

If you need to prevent item selection on right click, you can use 2 RadGrid client events:

1. Use OnRowClick to raise a flag indicating a row can be successfully selected. The OnRowClick client event is fired for left mouse button clicks only.

2. Use OnRowSelecting to cancel the selection of the current clicked item if no flag has been raised.

The combination of the above 2 events ensures that a right mouse button click does not select a grid item, it only shows the context menu. Attaching the modified test page."

All the best,
Veronica Milcheva
the Telerik team

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answered on 28 Sep 2010, 01:53 PM

As delivered, the sample code does not work. The rowSelecting event fires before RowClick, so _canSelect is set to true after the check has been made in rowSelecting. This causes the row selection to be denied. It never allows a row to be selected with either mouse click.

Additionally, the Context menu is designed to be driven off of the data in the grid, for a given row.

Here’s the issue: why doesn’t the RadGrid_SelectedIndexChanged event fire when the row is selected, not when the context menu item is clicked? To quote your response…’ You are getting RadGrid's server-side SelectedIndexChanged event fire, because a right click on a grid row selects the row.’ This does not appear to be true. The event is firing when the context menu item is clicked, not the grid row.

answered on 29 Sep 2010, 09:46 AM

Hello Zeke,

You cannot, actually. RadGrid cannot, by default, discern between left and right mouse clicks. The fact is, the MS AJAX framework does not fire click events for right mouse clicks. To verify, you can use the following test page:

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

</asp:ScriptManager>

<div id="div1" style="width:100px; height:100px; border:1px solid green">

</div>

<script type="text/javascript">

function pageLoad(sender, args)

{

var div1 = $get("div1");

$addHandler(div1, "click", function ()

{

alert("click1!");

});

}

</script>

Clicking on div1 with the left mouse button alerts "click!", but clicking with the right mouse button does not! Thus, RadGrid's RowClick event fires for left mouse clicks only. But item selection is triggered on mousedown, meaning you get item selection for both left and right mouse clicks. In effect, you do not have information about the clicked mouse button on item selection. Neither on the client nor on the server.

To work around this limitation, we need to use 2 different approaches:

1. For non-IE browsers, we need to raise a flag in OnRowClick, indicating a left mouse button click. Then we use OnRowSelecting to check this flag. This is how we know if left or right mouse button is clicked.

2. Approach 1 cannot be used in IE, because OnRowClick fires after OnRowSelecting. For IE, we need to check window.event.type. Its value is "click" for left mouse button click and "contextmenu" for right mouse button click. So, to disable item selection on right click, you have the following script:

function rowSelecting(sender, args)

{

if (!sender._canSelect &&

(!window.event ||

(window.event && window.event.type === "contextmenu"))) {

//alert('rowSelecting');

sender._canSelect = false;

args.set_cancel(true);

}

function rowClick(sender, args) {

//alert('rowClick');

sender._canSelect = true;

}

rowSelecting and rowClick are attached to the client grid events:

<ClientSettings>

<ClientEvents OnRowClick="rowClick" OnRowSelecting="rowSelecting" />

</ClientSettings>

Greetings,
Veli
the Telerik team