Memory leak caused by C UserControl

Test Engineering csdn Download address :https://download.csdn.net/download/wojiuguowei/85195072

Concept
out of memory ： The common understanding is that there is not enough memory , There is unrecoverable memory in the system or the memory used for program operation is greater than the maximum memory available , As a result “Out of memory” Or something like that , Make the program not work properly .

Memory leak ： Memory leak refers to the situation that the program cannot release or timely release the memory that is no longer used due to negligence or error , After the application allocates a certain section of memory , Because of a design mistake , Lost control of this segment of memory , As a result, the memory cannot be recycled and cannot be recycled in time , Finally, problems that may cause the program to run slowly or crash .

Possible causes of memory leaks ：
1、 Your object is still referenced but not actually used . Because they are quoted , therefore GC They will not be collected , In this way, they will be permanently saved and occupy memory .
2、 When you allocate unmanaged memory in some way （ There is no recycling ） And don't release them .

Derived classes inherit from UserControl, This control class contains picture、button Other controls
The example I tested , It is reflection that generates objects of this type , Use the default function Dispose Free memory , The test code is as follows

            while(true)
            {
				string tmp = string.Format("WindowsFormsApp10.UserControl1");
                Type type = Type.GetType(/*"LocalPLC.Base.PlcType"*/ tmp);


                if (type == null)
                {
                    return;
                }

                //object obj = type.Assembly.CreateInstance(type);
                UserControl1 user1 = (UserControl)Activator.CreateInstance(type) as UserControl1;

                user1.Dispose();

                GC.Collect();
                GC.WaitForPendingFinalizers();
                GC.Collect();
			}
               	

Above code , I thought I would recycle memory , But memory growth

Just started memory

Run for a period of time, memory

Memory does not increase , It has also dropped a lot , explain dipose You can delete the child controls in the control , If you are not at ease , You can add a... In the derived class clear function , Then traverse the child controls , Each child control is then dispose

        public  void Clear()
        {
            foreach (Control control in this.Controls)
            {
                {
                    control.Dispose();
                }
            }
        }

Reference link :
https://blog.csdn.net/qq_43360872/article/details/110846779
https://stackoverflow.com/questions/44371471/c-sharp-usercontrols-memory-leak
https://www.coder.work/article/6324862