Ping Monitor

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Configuration;
using System.Data.SqlClient;
using Microsoft.VisualBasic;

namespace PingMonitor
{
  public partial class frmConfig : Form
  {
    private DataTable dtHosts = new DataTable();
    private SqlDataAdapter daHosts;

    public frmConfig()
    {
      InitializeComponent();
    }

    private void frmConfig_Load(object sender, EventArgs e)
    {
      string ConnStr = ConfigurationManager.AppSettings["ConnStr"].ToString();
      daHosts = new SqlDataAdapter("SELECT * FROM HostList", ConnStr);
      SqlCommandBuilder cb = new SqlCommandBuilder(daHosts);
      daHosts.InsertCommand = cb.GetInsertCommand();
      daHosts.UpdateCommand = cb.GetUpdateCommand();
      daHosts.DeleteCommand = cb.GetDeleteCommand();

      ReLoadTree();
    }

    private void ReLoadTree()
    {
      dtHosts.Clear();
      daHosts.Fill(dtHosts);

      tvHosts.Nodes.Clear();
      tvHosts.Nodes.Add("All");
      LoadChildNodes("IDparent IS NULL", tvHosts.Nodes[0]);
      tvHosts.SelectedNode = tvHosts.Nodes[0];
    }

    private void LoadChildNodes(string Filter, TreeNode Node)
    {
      DataView dv = new DataView(dtHosts, Filter, "Host", DataViewRowState.Unchanged);
      DataRowView dr;
      for (int i = 0; i <= dv.Count - 1; i++)
      {
        dr = dv[i];
        Node.Nodes.Add(dr["Host"].ToString());
        Node.Nodes[i].Tag = dr;
        if ((!object.ReferenceEquals(dr["IsHost"], DBNull.Value)) && dr["IsHost"].ToString() == "Y")
        {
          Node.Nodes[i].ImageIndex = 1;
          Node.Nodes[i].SelectedImageIndex = 2;
        }
        else
        {
          Node.Nodes[i].ImageIndex = 0;
        }
        LoadChildNodes("IDparent=" + dr["ID"], Node.Nodes[i]);
        Node.Expand();
      }
    }

    private void mniDelete_Click(object sender, System.EventArgs e)
    {
      if (tvHosts.SelectedNode.Tag == null) return; // TODO: might not be correct. Was : Exit Sub

      DataRowView dr = (DataRowView)tvHosts.SelectedNode.Tag;
      if (dtHosts.Select("IDparent=" + dr["ID"]).Length > 0)
      {
        MessageBox.Show("You can only delete leaf nodes!", Application.ProductName, MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
        return; 
      }
      foreach (DataRow r in dtHosts.Rows)
      {
        if (r["ID"] == dr["ID"])
        {
          r.Delete();
          break; 
        }
      }
      daHosts.Update(dtHosts);
      ReLoadTree();
    }

    private void mniAddFolder_Click(object sender, System.EventArgs e)
    {
      object ParentID;
      if (tvHosts.SelectedNode.Tag == null)
      {
        ParentID = DBNull.Value;
      }
      else
      {
        DataRowView dr = (DataRowView)tvHosts.SelectedNode.Tag;
        if ((!object.ReferenceEquals(dr["IsHost"], DBNull.Value)) && dr["IsHost"].ToString() == "Y")
        {
          MessageBox.Show("You can only add children to folder nodes!", Application.ProductName, MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
          return; 
        }
        ParentID = dr["ID"];
      }

      DataRow r = dtHosts.NewRow();
      r["Host"] = "New folder";
      r["IsHost"] = DBNull.Value;
      r["ShowInMonitor"] = DBNull.Value;
      r["DoPing"] = DBNull.Value;
      r["PingFreq"] = DBNull.Value;
      r["IDparent"] = ParentID;
      dtHosts.Rows.Add(r);

      daHosts.Update(dtHosts);
      ReLoadTree();
    }

    private void tvHosts_AfterSelect(object sender, System.Windows.Forms.TreeViewEventArgs e)
    {
      if (tvHosts.SelectedNode.Tag == null)
      {
        // Root node
        pnlDetail.Visible = false;
      }
      else
      {
        pnlDetail.Visible = true;
        DataRowView dr = (DataRowView)tvHosts.SelectedNode.Tag;
        if ((!object.ReferenceEquals(dr["IsHost"], DBNull.Value)) && dr["IsHost"].ToString() == "Y")
        {
          // Host node
          chkDoPing.Visible = true;
          lblPingFreq.Visible = true;
          txtPingFreq.Visible = true;
          chkShowInMonitor.Visible = true;
          txtHost.Text = dr["Host"].ToString();
          if ((!object.ReferenceEquals(dr["DoPing"], DBNull.Value)) && dr["DoPing"].ToString() == "Y")
          {
            chkDoPing.Checked = true;
          }
          else
          {
            chkDoPing.Checked = false;
          }
          txtPingFreq.Text = dr["PingFreq"].ToString();
          if ((!object.ReferenceEquals(dr["ShowInMonitor"], DBNull.Value)) && dr["ShowInMonitor"].ToString() == "Y")
          {
            chkShowInMonitor.Checked = true;
          }
          else
          {
            chkShowInMonitor.Checked = false;
          }
        }
        else
        {
          // Folder node
          chkDoPing.Visible = false;
          lblPingFreq.Visible = false;
          txtPingFreq.Visible = false;
          chkShowInMonitor.Visible = false;
          txtHost.Text = dr["Host"].ToString();
        }
      }
    }

    private void chkDoPing_CheckedChanged(object sender, System.EventArgs e)
    {
      try
      {
        if (tvHosts.SelectedNode.Tag == null) 
          return; 
      }
      catch
      {
        return; 
      }
      txtPingFreq.Enabled = chkDoPing.Checked;
      chkShowInMonitor.Enabled = chkDoPing.Checked;
      DataRowView dr = (DataRowView)tvHosts.SelectedNode.Tag;
      if (chkDoPing.Checked)
      {
        dr["DoPing"] = "Y";
      }
      else
      {
        dr["DoPing"] = DBNull.Value;
      }
      daHosts.Update(dtHosts);
    }

    private void chkShowInMonitor_CheckedChanged(object sender, System.EventArgs e)
    {
      try
      {
        if (tvHosts.SelectedNode.Tag == null) 
          return; 
      }
      catch
      {
        return; 
      }
      DataRowView dr = (DataRowView)tvHosts.SelectedNode.Tag;
      if (chkShowInMonitor.Checked)
      {
        dr["ShowInMonitor"] = "Y";
      }
      else
      {
        dr["ShowInMonitor"] = DBNull.Value;
      }
      daHosts.Update(dtHosts);
    }

    private void txtPingFreq_LostFocus(object sender, System.EventArgs e)
    {
      try
      {
        if (tvHosts.SelectedNode.Tag == null) 
          return; 
      }
      catch
      {
        return; 
      }
      DataRowView dr = (DataRowView)tvHosts.SelectedNode.Tag;
      if (Information.IsNumeric(txtPingFreq.Text))
      {
        dr["PingFreq"] = int.Parse(txtPingFreq.Text);
        daHosts.Update(dtHosts);
      }
    }

    private void txtHost_LostFocus(object sender, System.EventArgs e)
    {
      try
      {
        if (tvHosts.SelectedNode.Tag == null) 
          return; 
      }
      catch
      {
        return; 
      }
      DataRowView dr = (DataRowView)tvHosts.SelectedNode.Tag;
      if (txtHost.Text.Trim() != "")
      {
        tvHosts.SelectedNode.Text = txtHost.Text.Trim();
        dr["Host"] = txtHost.Text.Trim();
        daHosts.Update(dtHosts);
      }
    }

    private void mniAddHost_Click(object sender, System.EventArgs e)
    {
      object ParentID;
      if (tvHosts.SelectedNode.Tag == null)
      {
        ParentID = DBNull.Value;
      }
      else
      {
        DataRowView dr = (DataRowView)tvHosts.SelectedNode.Tag;
        if ((!object.ReferenceEquals(dr["IsHost"], DBNull.Value)) && dr["IsHost"].ToString() == "Y")
        {
          MessageBox.Show("You can only add children to folder nodes!", Application.ProductName, MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
          return; 
        }
        ParentID = (int)dr["ID"];
      }

      DataRow r = dtHosts.NewRow();
      r["Host"] = "New host";
      r["IsHost"] = "Y";
      r["ShowInMonitor"] = "Y";
      r["DoPing"] = "Y";
      r["PingFreq"] = 60;
      r["IDparent"] = ParentID;
      dtHosts.Rows.Add(r);

      daHosts.Update(dtHosts);
      ReLoadTree();
    }

  }
}