另一个SqlParamenterCollection已包含SqlParamenter
protected void btnUpdate_Click(object sender, EventArgs e)
  {
  string sql = " update [UserInfo] set UserName =@UserName ,Sex=@Sex,Age=@Age,Descripition=@Descripition,Position=@Position";
  if (GetMD5(txtPassword.Text.Trim()).Length > 0)
  {
  sql += ",Pwd=@Pwd";
  }
  sql += " where [ID]=@ID";

  SqlParameter[] parameters = new SqlParameter[8];

  SqlParameter name = new SqlParameter("@UserName", SqlDbType.VarChar);
  name.Value = this.txtName.Text;
  parameters[0] = name;

   
  SqlParameter sex = new SqlParameter("@Sex", SqlDbType.Int);
  sex.Value = int.Parse(this.rdlSex.SelectedValue);
  parameters[1] = sex;

  SqlParameter age = new SqlParameter("@Age", SqlDbType.Int);
  sex.Value = int.Parse(this.txtAge.Text.Trim());
  parameters[2] = sex;

  SqlParameter description = new SqlParameter("@Descripition", SqlDbType.VarChar);
  description.Value = this.ddlDes.Text;
  parameters[3] = description;

  SqlParameter position = new SqlParameter("@Position", SqlDbType.VarChar);
  description.Value = this.ddlDes.Text;
  parameters[4] = description;

  SqlParameter password = new SqlParameter("@Pwd", SqlDbType.VarChar);
  password.Value = GetMD5(this.txtPassword.Text.Trim());
  parameters[5] = password;

  SqlParameter id = new SqlParameter("ID", SqlDbType.VarChar);
  id.Value =this.hfdUserID.Value;
  parameters[6] = id;


  try
  {
  bool result = dbHelper.ExecuteNonQuery(sql, parameters);
  Response.Write("<script type='text/javascript'> alert('更新成功');</script>");

  }
  catch (Exception ex)
  {
  Response.Write("<script type='text/javascript'> alert('更新失败，失败原因：" + ex.Message + "');</script>");

  }

  }


  private DataRow GetUser(string id) 
  {
  string sql = "select * from [UserInfo] where ID=@ID";
  SqlParameter paramID = new SqlParameter("@ID", SqlDbType.VarChar);
  paramID.Value = this.hfdUserID.Value;

  DataTable dtData;
  try
  {
  dtData = dbHelper.Select(sql, new SqlParameter[] { paramID });

  }
  catch (Exception ex)
  {
  throw ex;
  }

  if (dtData.Rows.Count > 0)
  {
  return dtData.Rows[0];
  }
  else
  {
  return null;
  }
  }

各位大神求教。

------解决方案--------------------
太粗心啦

protected void btnUpdate_Click(object sender, EventArgs e)
{
string sql = " update [UserInfo] set UserName =@UserName ,Sex=@Sex,Age=@Age,Descripition=@Descripition,Position=@Position";
if (GetMD5(txtPassword.Text.Trim()).Length > 0)
{
sql += ",Pwd=@Pwd";
}
sql += " where [ID]=@ID";

SqlParameter[] parameters = new Sql