c#怎么在后台载入地图，载入数据啊求教

求教啊，要求打开winform之后，地图在后台自动就载入了，不用再像下边的代码一样，打开默认路径，选择文件在载入了。如何修改呀~~~
        private void buttonX2_Click(object sender, EventArgs e)
        {
            slider2.Value = 0;  //进度条清零，初始化
            OpenFileDialog openMXD = new OpenFileDialog();
            openMXD.Title = "打开";
            openMXD.InitialDirectory = Constant.DEFAULT_PATH;//设置默认打开路径
            openMXD.Filter = "Map Documents (*.mxd)|*.mxd";//设定文件类型
            if (openMXD.ShowDialog() == DialogResult.OK)
            {
                String mxdpath = openMXD.FileName;
                axMapControl1.LoadMxFile(mxdpath);
                IMpMap = axMapControl1.Map;
                for (int i = 0; i <= 100; i++)  //载入 假的样式的进度条
                {
                    this.progressBarX1.PerformStep();
                }
                this.initEnabled();  //未载入地图之前，所有的按钮都不能使用，这是载入地图之后对初值的修改
            }