鼠标滚轮放大缩小方向修改

AE开发程序，鼠标滚轮放大缩小方向修改问题：
/// <summary>
/// 滚动鼠标中键，往前地图放大，往后缩小 /// </summary>
void ReverseMouseWheel()
{
try
{
RegistryKey setKey;
//打开 HKEY_CURRENT_USER\Software\ESRI\ArcMap\Settings
setKey = Registry.CurrentUser.OpenSubKey("Software\\ \\ESRI\\\\ArcMap\\\\Settings", true);
if (setKey != null)
{
if (setKey.GetValue("ReverseMouseWheel") == null)
{
setKey.SetValue("ReverseMouseWheel", "0",RegistryValueKind.DWord);
}
else if (setKey.GetValue("ReverseMouseWheel").ToString() != "0")
{
setKey.SetValue("ReverseMouseWheel", "0");
}
}

}
catch { }
}