Get Source Control Of DropDownMenu

问题:

I have two click events of menu items in a context menu strip. I can get the source control of the clicked context menu item by doing this code:

Control c = ((sender as ToolStripItem).Owner as ContextMenuStrip).SourceControl;

Screenshot of the context menu item

But when I use this code on a context menu item that is in another level it returns null.

Screenshot of the context menu item in another level

How can I get the sourcecontrol in the click event of the second screenshot's menu item?

回答1:

The ContextMenuStrip SourceControl (the reference of the current Control where the Context Menu is activated) can be retrieved, from a ToolStripMenuItem, inspecting the OwnerItem reference and moving upstream until the OwnerItem reference is null, then inspecting the Owner value, which references the ContextMenuStrip.
(Unfortunately, the SourceControl reference is only available in the ContextMenuStrip control).

A simple alternative method is using a Field that references the Control where the current ContextMenuStrip has been activated (you can have just one active ContextMenuStrip).
This Field reference, set when the ContextMenuStrip is opened - by subscribing to the Opened() event - can then be accessed by any of the ToolStripMenuItem.
The Field reference is then set back to null when then ContextMenuStrip is closed.

An example:
(toolStripMenuItem is a generic name, it must be set to an actual control name).

Control CurrentContextMenuOwner = null;

private void contextMenuStrip1_Opened(object sender, EventArgs e)
{
    CurrentContextMenuOwner = (sender as ContextMenuStrip).SourceControl;
}

private void toolStripMenuItem_Click(object sender, EventArgs e)
{
    CurrentContextMenuOwner.BackColor = Color.Blue;
    //(...)
}

private void contextMenuStrip1_Closed(object sender, ToolStripDropDownClosedEventArgs e)
{
    CurrentContextMenuOwner = null;
}