释放内存

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Drawing;
using System.IO;
using System.Runtime.InteropServices;
using System.Windows.Forms;

[DllImport("kernel32.dll")]
private static extern bool SetProcessWorkingSetSize(IntPtr process, int minSize, int maxSize);
//关闭窗体按钮 
private void btnReturn_Click(object sender, EventArgs e)
{
　　this.Close();
　　FlushMemory();
}
//刷新存储器
private static void FlushMemory()
{
　　GC.Collect();
　　GC.WaitForPendingFinalizers();
　　if (Environment.OSVersion.Platform == PlatformID.Win32NT)
　　{
　　　　SetProcessWorkingSetSize(Process.GetCurrentProcess().Handle, -1, -1);
　　}　
}

方法2：
[DllImport("kernel32.dll", EntryPoint = "SetProcessWorkingSetSize")]
        public static extern int SetProcessWorkingSetSize(IntPtr process, int minSize, int maxSize);

        /// <summary>
        /// 释放内存
        /// </summary>
        public static void ClearMemory()
        {
            GC.Collect();
            GC.WaitForPendingFinalizers();
            if (Environment.OSVersion.Platform == PlatformID.Win32NT)
            {
                SetProcessWorkingSetSize(Process.GetCurrentProcess().Handle, -1, -1);
            }
        }