Child ContextMenuStrip

Question

I have a container with a control inside. I have a ContextMenuStrip assigned to both of these. What I want to happen is for the contextmenu of the control to also contain all the items from the container. However, when I try

ToolStripManager.Merge(this.ContextMenuStrip, this.Parent.ContextMenuStrip);

The contextmenu for the whole container is removed

EDIT: OK, I guess I need to clarify. The code I have works to some extent. this.ContextMenuStrip is a property of the control to which I have assigned one menu, and this.Parent.ContextMenuStrip I have assigned a different menu. When I merge them, all of the items of the parent's menu show up in the child's menu, but the parent no longer has a menu.

This is how I set the menus:

this.ContextMenuStrip = contextmenu1;
this.Parent.ContextMenuStrip = contextmenu2;

OK, here's the code

The Form1.Designer.cs:

namespace FailExample
{
    partial class Form1
    {
        /// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows Form Designer generated code

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.components = new System.ComponentModel.Container();
            this.button1 = new System.Windows.Forms.Button();
            this.contextMenuStrip2 = new System.Windows.Forms.ContextMenuStrip(this.components);
            this.item2ToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
            this.contextMenuStrip1 = new System.Windows.Forms.ContextMenuStrip(this.components);
            this.item1ToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
            this.contextMenuStrip2.SuspendLayout();
            this.contextMenuStrip1.SuspendLayout();
            this.SuspendLayout();
            // 
            // button1
            // 
            this.button1.ContextMenuStrip = this.contextMenuStrip2;
            this.button1.Location = new System.Drawing.Point(86, 82);
            this.button1.Name = "button1";
            this.button1.Size = new System.Drawing.Size(75, 23);
            this.button1.TabIndex = 0;
            this.button1.Text = "button1";
            this.button1.UseVisualStyleBackColor = true;
            // 
            // contextMenuStrip2
            // 
            this.contextMenuStrip2.Items.AddRange(new System.Windows.Forms.ToolStripItem[] {
            this.item2ToolStripMenuItem});
            this.contextMenuStrip2.Name = "contextMenuStrip2";
            this.contextMenuStrip2.Size = new System.Drawing.Size(105, 26);
            // 
            // item2ToolStripMenuItem
            // 
            this.item2ToolStripMenuItem.Name = "item2ToolStripMenuItem";
            this.item2ToolStripMenuItem.Size = new System.Drawing.Size(104, 22);
            this.item2ToolStripMenuItem.Text = "Item2";
            // 
            // contextMenuStrip1
            // 
            this.contextMenuStrip1.Items.AddRange(new System.Windows.Forms.ToolStripItem[] {
            this.item1ToolStripMenuItem});
            this.contextMenuStrip1.Name = "contextMenuStrip1";
            this.contextMenuStrip1.Size = new System.Drawing.Size(105, 26);
            // 
            // item1ToolStripMenuItem
            // 
            this.item1ToolStripMenuItem.Name = "item1ToolStripMenuItem";
            this.item1ToolStripMenuItem.Size = new System.Drawing.Size(104, 22);
            this.item1ToolStripMenuItem.Text = "Item1";
            // 
            // Form1
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(284, 261);
            this.ContextMenuStrip = this.contextMenuStrip1;
            this.Controls.Add(this.button1);
            this.Name = "Form1";
            this.Text = "Form1";
            this.Load += new System.EventHandler(this.Form1_Load);
            this.contextMenuStrip2.ResumeLayout(false);
            this.contextMenuStrip1.ResumeLayout(false);
            this.ResumeLayout(false);

        }

        #endregion

        private System.Windows.Forms.Button button1;
        private System.Windows.Forms.ContextMenuStrip contextMenuStrip2;
        private System.Windows.Forms.ToolStripMenuItem item2ToolStripMenuItem;
        private System.Windows.Forms.ContextMenuStrip contextMenuStrip1;
        private System.Windows.Forms.ToolStripMenuItem item1ToolStripMenuItem;
    }
}

And the Form1.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace FailExample
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            ToolStripManager.Merge(button1.Parent.ContextMenuStrip, button1.ContextMenuStrip);
        }
    }
}

Answer 1

I get a NullReferenceException when I try your example. But this works for me:

ToolStripManager.Merge(contextMenuStrip1, contextMenuStrip2);

I think your references to ContextMenuStrips are false or identical.

When I look at the info VS shows on mouse over:

• this.ContextMenuStrip refers to the underlaying form
• this.Parent.ContextMenuStrip refers to the parent of the form (which is null)
• anyway none of the references refer to the context menu of your ToolStripContainer