调用AnimateWindow方法，是不是属于调用Windows API？
public partial class Formdonghua : Form { //动画窗体调用,关闭时将向上移出屏幕 [System.Runtime.InteropServices.DllImport("user32")] private static extern bool AnimateWindow(IntPtr hwnd, int dwTime, int dwFlags); const int AW_HOR_POSITIVE = 0x0001; const int AW_HOR_NEGATIVE = 0x0002; const int AW_VER_POSITIVE = 0x0004; const int AW_VER_NEGATIVE = 0x0008; const int AW_CENTER = 0x0010; const int AW_HIDE = 0x10000; const int AW_ACTIVATE = 0x20000; const int AW_SLIDE = 0x40000; const int AW_BLEND = 0x80000; //………………………………………………………… public Formdonghua() { InitializeComponent(); } private void Formdonghua_Load(object sender, EventArgs e) { //动画由小渐大,现在取消 AnimateWindow(this.Handle, 1000, AW_CENTER | AW_ACTIVATE); //主界面渐变设置 this.jianbian.Enabled = true;//让jianbian的timer值有效 this.Opacity = 0; //……………………………………………… } private void jianbian_Tick(object sender, EventArgs e) { //让背景由0变到1 if (this.Opacity < 1) { this.Opacity = this.Opacity + 0.05; } else { this.jianbian.Enabled = false; } } private void Formdonghua_FormClosing(object sender, FormClosingEventArgs e) {//关闭时动画 AnimateWindow(this.Handle, 1000, AW_SLIDE | AW_HIDE | AW_VER_NEGATIVE); } }