C# 数据恢复Kill进程问题

C# code:
try
{
ofd.Filter = @"备份文件(*.bak)|*.bak|所有文件(*.*)|*.*”";
ofd.FilterIndex = 1;
this.textBox1.Text = ofd.FileName.ToString();
if (ofd.ShowDialog() == DialogResult.OK)
{
string DateStr = "Data Source=.;Initial Catalog=enrol;Integrated Security=True";
SqlConnection conn = new SqlConnection(DateStr);
conn.Open();
/*杀掉所有连接数据库的进程 */
string strSQL = "select spid from master..sysprocesses where dbid=db_id('enrol')";
SqlDataAdapter Da = new SqlDataAdapter(strSQL, conn);

DataTable spidTable = new DataTable();
Da.Fill(spidTable);

SqlCommand Cmd = new SqlCommand();
Cmd.CommandType = CommandType.Text;
Cmd.Connection = conn;

for (int iRow = 0; iRow <= spidTable.Rows.Count - 1; iRow++)
{
//MessageBox.Show(spidTable.Rows[iRow][0].ToString());
Cmd.CommandText = "kill " + spidTable.Rows[iRow][0].ToString(); //强行关闭用户进程
Cmd.ExecuteNonQuery();