C＃：当链接到两个不同的对象时，如何检测谁是上下文菜单菜单项的调用者？

Question

C#: How to detect who is the caller of a context menu's menu item when linked to two different objects?

I have two labels, lblOn and lblOff. I am linking 'one' contextmenu to both labels to discard having to make two of the same.

How would I go upon finding out which label object called the contextmenu.menuitem? That way the clicked on menuitem knows if it was it it's contextmenu was called by the lblOn label or lblOffline?

Answer 1

检查ContextMenuStrip的SourceControl属性。

Answer 2

Disregard. After googling a bit more, I found a solution + code example.

private void deleteToolStripMenuItem_Click(object sender, EventArgs e)
{
    //Make sure the sender is a ToolStripMenuItem
    ToolStripMenuItem myItem = sender as ToolStripMenuItem;
    if (myItem != null)
    {
        //Get the ContextMenuString (owner of the ToolsStripMenuItem)
        ContextMenuStrip theStrip = myItem.Owner as ContextMenuStrip;
        if (theStrip != null)
        {
            //The SourceControl is the control that opened the contextmenustrip.
            //In my case it could be a linkLabel
            LinkLabel linkLabel = theStrip.SourceControl as LinkLabel;
            if (linkLabel == null)
                MessageBox.Show("Invalid item selected.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            else
            {
                if (MessageBox.Show(string.Format("Are you sure you want to remove BOL {0} from this Job?", linkLabel.Text), "Confirm Delete", MessageBoxButtons.YesNo, MessageBoxIcon.Question) == DialogResult.Yes)
                {
                    linkLabel.Text = Program.NullValue(linkLabel);
                }
            }
        }
    }
}

Source: http://www.tek-tips.com/viewthread.cfm?qid=1441041&page=8

Answer 3

I know this is a question from many moons ago but I havent really been able to find a simple answer with code... I know SLaks kind of pointed it out, but I think others out there need a code sample...

I wanted to know who the called the context menu between either a rich text box or a label. The reason is I wanted only one context menu and wanted the copy button within it to be disabled if the caller was the rich text box with nothing selected.

Heres my code:

    private void contextMenuStrip1_Opened(object sender, EventArgs e)
    {
        //get the context menu (it holds the caller)
        ContextMenuStrip contextMenu = sender as ContextMenuStrip;
        //get the callers name for testing 
        string controlName = contextMenu.SourceControl.Name;

        //test if it is infact me rich text editor making the call.
        if (controlName == "text_rchtxt")
        {
            //if I have nothing selected... I should not be able to copy
            if (text_rchtxt.SelectedText == "")
                copy_shrtct.Enabled = false; 
        }
        else
        {
            //if I do have something selected or if its another control making the call, enable copying
            copy_shrtct.Enabled = true;
        }
    }

Answer 4

用这个：

contextMenuStrip1.SourceControl;