Suppose we have Data in the Table named Category as follows

Now to bind this to the tree,we will use a recursive function.Also for better performance,we will bind the database results into a global DataTable first and then apply filtering.

Here is the Code to bind to the DataTable.

 private void bindDataTable()
    {
       
        string strConn = ConfigurationManager.ConnectionStrings["yourConnectionName"].ConnectionString;
        SqlConnection conn = new SqlConnection(strConn);
        SqlCommand cmd = new SqlCommand("Select * from Category", conn);
        cmd.CommandType = CommandType.Text;
       
        SqlDataAdapter sqlDa = new SqlDataAdapter();
        sqlDa.SelectCommand = cmd;
        sqlDa.Fill(dt);
        conn.Close();

    }

Now we will add a recursive method that will make use of this DataTable to build the TreeView.

private void buildNodes(TreeNode n, int? categoryId)
    {
        DataRow[] drCategories;
        if (categoryId == null)
            drCategories = dt.Select("NodeLevel=0"); // This will get the Root Node
        else
            drCategories = dt.Select("ParentIdFK='" + categoryId + "'");

        foreach (DataRow dr in drCategories)
        {
            TreeNode t = new TreeNode();
            t.Text = dr["CategoryName"].ToString();
            t.Value = dr["CategoryId"].ToString();    
           
            buildNodes(t, Convert.ToInt32(dr["CategoryId"].ToString()));// Calling the function resursively
            if (n == null)// If it is Root Node
                TreeView1.Nodes.Add(t);
            else
                n.ChildNodes.Add(t);

        }

Above we are using int? so that int type can accept null values.

So now all we have to do is call these methods.

  protected void Page_Load(object sender, EventArgs e)
     {
         if (!IsPostBack)
         {
              bindDataTable();
              buildNodes(null, null);//CategoryId=null is passed which is the ParentId of the Root Node
         }
     }

Now you can add some formatting and Css as you may please to get a better looking Treeview.Happy Coding Folks!!!

Here is the code to  convert a string in CSV format ot an integer array.

 
public int[] StringToArray(string input)
        {
            string[] stringList = input.Split(",".ToCharArray(),
                                              StringSplitOptions.RemoveEmptyEntries);
           
            int[] ids = new int[stringList.Length];

            for (int i = 0; i < stringList.Length; i++)
            {
                ids[i] = (int)Convert.ChangeType(stringList[i], typeof(int));
            }

            return ids;  
        }

 
Here instead of the “,” delimiter you can make use of the delimiter used in your format

Public Class Product()
{
public product(){ }
public string productName;
public float productPrice;
}

Now to create an XML representation of the object of class Product,we can make use of the XmlSerializer class in .Net.Here is the C# code for implementing serialization.

Product p=new Product();
p.productName="product1";
p.productPrice=12.00;
XmlSerializer serializer=new XmlSerializer(typeOf(Product));
StringWriter sw=new StringWriter();
serializer.Serialize(sw,p);
sw.Close(); 

 
Here is another example.In the below code,i have an object of class Product,which contains Product Information.when i run the webservice,i have to pass the ProductId(second line) to get the information and the webservice will automatically generate an XML file containing the details.Now what do we do if we have to save this information to another XML file so that we have the information even after the web service is stopped or in more technical terms we want the data to be persistent.

Namespace used: System.Xml.Serialization;      

Product productXml = new Product();
productXml = application.getProducts().getProductInfo(id);//build the product object
XmlSerializer serialize = new XmlSerializer(typeof(Product));
TextWriter tw = new StreamWriter(Server.MapPath("Products.xml"));
serialize.Serialize(tw, productXml);
tw.Close();

Dont forget to include System.IO,else you wont be able to use TextWriter and StreamWriter.

using system.net;

string strHostName = string.Empty;

cmbIPAddress.Items.Clear();//combo box to hold the ip address

strHostName = Dns.GetHostName();//get name of the local machine

IPHostEntry ipEntry = Dns.GetHostByName(strHostName);
IPAddress[] iparrAddr = ipEntry.AddressList
if (iparrAddr.Length > 0)
{
for (int intLoop = 0; intLoop < iparrAddr.Length; intLoop++)
cmbIPAddress.Items.Add(iparrAddr[intLoop].ToString());
}

Getting the ip addresses of machines connected through LAN


First Get the names of the machines

using System.Net;
using System.Diagnostics;
using System.IO;

Process netUtility = new Process();

netUtility.StartInfo.FileName = "net.exe";
netUtility.StartInfo.CreateNoWindow = true;
netUtility.StartInfo.Arguments = "view";
netUtility.StartInfo.RedirectStandardOutput = true;
netUtility.StartInfo.UseShellExecute = false;
netUtility.StartInfo.RedirectStandardError = true;
netUtility.Start();

StreamReader streamReader = new StreamReader(netUtility.StandardOutput.BaseStream, netUtility.StandardOutput.CurrentEncoding);

string line = "";
while ((line = streamReader.ReadLine()) != null)
{
if (line.StartsWith("\\"))
{
cmbnetworkcomputers.Items.Add(line.Substring(2).Substring(0, line.Substring(2).IndexOf(" ")).ToUpper());//cmbnetworkcomputers is a combobox

}

}
streamReader.Close();
netUtility.WaitForExit(1000);

Now to get the ip addrresses,use these names

for (int i = 0; i < cmbnetworkcomputers.Items.Count; i++)
{
string st;
st = cmbnetworkcomputers.Items[i].ToString();
IPHostEntry ipEntry = Dns.GetHostByName(st);
IPAddress[] iparrAddr = ipEntry.AddressList;
if (iparrAddr.Length > 0)
{
for (int intLoop = 0; intLoop < iparrAddr.Length; intLoop++)
cmbIPAddress.Items.Add(iparrAddr[intLoop].ToString());//combobox to hold Ip Address
}
}

System.Diagnostics namespace contains a class Process which provides the functionality to monitor processes connected across a network as well as the local machine

Running another exe file

System.Diagnostics.Process.Start("pathofexefile");
System.Diagnostics.Process.Start("notepad.exe");

Killing a currently running process

Process[] processes = Process.GetProcessesByName("googletalk");
foreach (Process p in processes)
{
Process.GetProcessById(p.Id).Kill();
}