重载ProcessCmdKey实现回车转换焦点(转于网络)

protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
        {
            if (keyData == Keys.Enter)
            {
                System.Windows.Forms.SendKeys.Send("{tab}");
                return true;
            }

            return base.ProcessCmdKey(ref msg, keyData);
        }

重载ProcessCmdKey实现将“回车”命令转换“tab”命令，从而实现转换焦点。

if(m.Msg == WM_KEYDOWN&& keyCode == Keys.Enter )
{
m.WParam=(IntPtr)Keys.Tab
}
return base.ProcessKeyPreview(ref m);