. NET trap three "correct" use controls can also cause memory leaks

In our code, there are times when you add a reference to a data object in a control. For example, use the Tag property of the tree node to save the object so that it can be easily accessed in the interface operation. Because the data is not referenced elsewhere, we expect the garbage collection mechanism to reclaim the appropriate memory when the control is destroyed. But when the software runs for a while, memory usage becomes very large. The following is a simplified sample code:

Using System;   
        
 Using System.Windows.Forms;   
         Namespace Memoryleak {public class Mainform:form {private Button Holderbutton;   
         Private Button Controlbutton;   
         Private FlowLayoutPanel panel;   
        
         Private Object CHECKGC;   
             Public MainForm () {dumpmemoryusage ("before allocate checkgc.");   
             CHECKGC = Makelargeobject ();   
        
             Dumpmemoryusage ("After allocate checkgc.");   
             Holderbutton = new Button ();   
             holderbutton.enabled = false;   
             Holderbutton.autosize = true;   
             Holderbutton.text = "The button holds large object."   
             Dumpmemoryusage ("Before allocate Holderbutton.tag.");   
             Holderbutton.tag = Makelargeobject ();   
        
             Dumpmemoryusage ("After allocate Holderbutton.tag.");   
             Controlbutton = new Button (); ContrOlbutton.autosize = true;   
             Controlbutton.text = "the button controls Holderbutton."  Controlbutton.click + = (sender, E) => {dumpmemoryusage ("before release CHECKGC and   
                 Holderbutton.tag. "); Panel.   
                 Controls.remove (Holderbutton);   
                 Holderbutton.dispose ();   
        
                 Holderbutton = null;   
                 CHECKGC = null;   
             Dumpmemoryusage ("After release CHECKGC and Holderbutton.tag.");   
        
             };   
             panel = new FlowLayoutPanel (); Panel.   
             AutoSize = true; Panel.   
             FlowDirection = Flowdirection.topdown; Panel.   
             Controls.Add (Controlbutton); Panel.   
        
             Controls.Add (Holderbutton);   
         Controls.Add (panel); private void Dumpmemoryusage (String msg) {GC.   
             Collect (); Console.   
             WriteLine (msg); Console.WriteLine (GC.   
         Gettotalmemory (true));   
             Private Object Makelargeobject () {var largeobject = new object[100]; for (int i = 0; i < largeobject.length ++i) {var array = new Int[1   
                 00][];   
                 Largeobject[i] = array; for (int j = 0; J < array.) Length;   
                 ++J) {Array[j] = new INT[100];   
         } return largeobject; } static class Program {static void Main () {A Pplication.   
         Run (New MainForm ()); }   
     }   
 }

The CHECKGC variable in the code is to confirm that the garbage collection has already been made in the output. The following are the output results:

Before allocate CHECKGC.   
 281576 after   
 allocate CHECKGC.   
 4605632   
 before allocate holderbutton.tag.   
 4606384 after   
 allocate holderbutton.tag.   
 8930480   
 before release CHECKGC and Holderbutton.tag.   
 8940016 after release   
 CHECKGC and Holderbutton.tag.   
 4616824