怎么正确关闭屏幕键盘？直接用CloseMainWindow();会报错
以下代码， 当我在保存文件前用鼠标点屏幕键盘的红叉时，会报错。如果不关闭键盘，就不会有问题。
问题是， 我怎么来判断这个屏幕键盘（进程）是否已经在其它地方被关闭了呢？
谢谢

C# code

           System.Diagnostics.Process prKeyBoard = System.Diagnostics.Process.Start("osk.exe");            if (saveFile.ShowDialog() == DialogResult.OK)            {                //  ...                // 关闭屏幕键盘                if (prKeyBoard != null)                {                    prKeyBoard.CloseMainWindow();                    /// prKeyBoard.Close();                }            }

[解决办法]
参考以下代码，稍作修改就可以
[code=C#]
/// <summary>
/// 打开窗体
/// </summary>
/// <param name="mdiChildTypeString"></param>
/// <returns></returns>
private void ShowWindow(string mdiChildTypeString)
{
Form currentMdiChild = null;

if (!IsMDIChildFormExist(mdiChildTypeString))
{
Assembly assembly = Assembly.GetExecutingAssembly();
Type typForm = assembly.GetType(mdiChildTypeString);

Object mdiChild = typForm.InvokeMember(
null,
BindingFlags.DeclaredOnly | BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.CreateInstance,
null,
null,
null);

if (mdiChild != null)
{
currentMdiChild = mdiChild as Form;
currentMdiChild.MdiParent = this;
//currentMdiChild.WindowState = FormWindowState.Maximized;
currentMdiChild.Show();
currentMdiChild.Focus();
}
}
}
[code]
[解决办法]

C# code

/// <summary>        /// 检查MDI子窗体是否存在        /// </summary>        /// <param name="mdiChildTypeString"></param>        /// <returns></returns>                private bool IsMDIChildFormExist(string mdiChildTypeString)        {            Form currentMDIChild = null;            foreach (Form mdiChildFrm in this.MdiChildren)            {                if (mdiChildFrm.GetType().ToString() == mdiChildTypeString)                {                    currentMDIChild = mdiChildFrm;                    break;                }            }            if (currentMDIChild != null)            {                if (currentMDIChild.WindowState == FormWindowState.Minimized)                {                    currentMDIChild.WindowState = FormWindowState.Normal;                }                currentMDIChild.TopMost = true;                currentMDIChild.Activate();                currentMDIChild.Focus();                return true;            }            else            {                return false;            }        }