(C#) ASP.NET DropDownlist & DataBinding

<%@ Import Namespace="System.Data"%>
<%@ Import Namespace="System.Data.OleDb"%>
<%@ Page Language="C#" Debug="true" %>
<script runat="server">

    void Page_Load(object sender, EventArgs e)
	{
		if(!Page.IsPostBack)
		{
			DropDownListDataTable();
			DropDownListDataTableRows();
			DropDownListSortedList();
			DropDownListAddInsertItem();
		}
    }

	//*** DropDownList & DataTable ***//
	void DropDownListDataTable()
	{
		OleDbConnection objConn;
		OleDbDataAdapter dtAdapter;
		DataTable dt = new DataTable();
			  
	   String strConnString;
	   strConnString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source="+
	   Server.MapPath("database/mydatabase.mdb")+"";
	   objConn = new OleDbConnection(strConnString);
	   objConn.Open();

		String strSQL;	
		strSQL = "SELECT * FROM country";

		dtAdapter = new OleDbDataAdapter(strSQL, objConn);
		dtAdapter.Fill(dt);

		dtAdapter = null;
		objConn.Close();
		objConn = null;

		//*** DropDownList ***//
		this.myDDL1.DataSource = dt;
		this.myDDL1.DataTextField = "CountryName";
		this.myDDL1.DataValueField = "CountryCode";
		this.myDDL1.DataBind();		
		
		//*** Default Value ***//
		myDDL1.SelectedIndex = myDDL1.Items.IndexOf(myDDL1.Items.FindByValue("TH"));  //*** By DataValueField ***//
		//myDDL1.SelectedIndex = myDDL1.Items.IndexOf(myDDL1.Items.FindByText("Thailand"));  //*** By DataTextField ***//

	}

	//*** DropDownList & TableRows ***//
	void DropDownListDataTableRows()
	{
        DataTable dt = new DataTable();
        DataRow dr;
		
		//*** Column ***//
        dt.Columns.Add("Sex");
        dt.Columns.Add("SexDesc");
		
		//*** Rows ***//
		dr = dt.NewRow();
        dr["Sex"] = "M";
        dr["SexDesc"] = "Man";
        dt.Rows.Add(dr);

		//*** Rows ***//
		dr = dt.NewRow();
        dr["Sex"] = "W";
        dr["SexDesc"] = "Woman";
        dt.Rows.Add(dr);

		//*** DropDownList ***//
		this.myDDL2.DataSource = dt;
		this.myDDL2.DataTextField = "SexDesc";
		this.myDDL2.DataValueField = "Sex";
		this.myDDL2.DataBind();

		//*** Default Value ***//
		myDDL2.SelectedIndex = myDDL2.Items.IndexOf(myDDL2.Items.FindByValue("W"));  //*** By DataValueField ***//
		//myDDL2.SelectedIndex = myDDL2.Items.IndexOf(myDDL2.Items.FindByText("Woman"));  //*** By DataTextField ***//

	}

	//*** DropDownList & SortedList ***//
	void DropDownListSortedList()
	{
        SortedList mySortedList = new SortedList();
		
		mySortedList.Add("M","Man");
		mySortedList.Add("W","Woman");

		//*** DropDownList ***//
		this.myDDL3.DataSource = mySortedList;
		this.myDDL3.DataTextField = "Value";
		this.myDDL3.DataValueField = "Key";
		this.myDDL3.DataBind();

	
		//*** Default Value ***//
		myDDL3.SelectedIndex = myDDL3.Items.IndexOf(myDDL3.Items.FindByValue("W"));  //*** By DataValueField ***//
		//myDDL3.SelectedIndex = myDDL3.Items.IndexOf(myDDL3.Items.FindByText("Woman"));  //*** By DataTextField ***//
	}


	//*** Add/Insert Items ***//
	void DropDownListAddInsertItem()
	{
        SortedList mySortedList = new SortedList();
		
		mySortedList.Add("M","Man");
		mySortedList.Add("W","Woman");

		//*** DropDownList ***//
		this.myDDL4.DataSource = mySortedList;
		this.myDDL4.DataTextField = "Value";
		this.myDDL4.DataValueField = "Key";
		this.myDDL4.DataBind();		


		//*** Add & Insert New Item ***//
		String strText,strValue;

		//*** Insert Item ***//
		strText = "";
		strValue = "";
		ListItem InsertItem = new ListItem(strText, strValue);
		myDDL4.Items.Insert(0, InsertItem);

		//*** Add Items ***//		
		strText = "Guy";
		strValue = "G";
		ListItem AddItem = new ListItem(strText, strValue);
		myDDL4.Items.Add(AddItem);	

		//*** Default Value ***//
		myDDL4.SelectedIndex = myDDL4.Items.IndexOf(myDDL4.Items.FindByValue(""));  //*** By DataValueField ***//
		//myDDL4.SelectedIndex = myDDL4.Items.IndexOf(myDDL4.Items.FindByText(""));  //*** By DataTextField ***//
	}

    void Button1_OnClick(object sender, EventArgs e)
	{
        this.lblText1.Text = this.myDDL1.SelectedItem.Value;  //*** Or this.myDDL1.SelectedItem.Text ***//
		this.lblText2.Text = this.myDDL2.SelectedItem.Value;  //*** Or this.myDDL2.SelectedItem.Text ***//
		this.lblText3.Text = this.myDDL3.SelectedItem.Value;  //*** Or this.myDDL3.SelectedItem.Text ***//
		this.lblText4.Text = this.myDDL4.SelectedItem.Value;  //*** Or this.myDDL4.SelectedItem.Text ***//
    }

</script>
<html>
<head>
<title>ThaiCreate.Com ASP.NET - DropDownList & DataBind</title>
</head>
<body>
	<form id="form1" runat="server">
		<asp:DropDownList id="myDDL1" runat="server"></asp:DropDownList> 
		<asp:DropDownList id="myDDL2" runat="server"></asp:DropDownList>
		<asp:DropDownList id="myDDL3" runat="server"></asp:DropDownList>
		<asp:DropDownList id="myDDL4" runat="server"></asp:DropDownList>
		<asp:Button id="Button1" onclick="Button1_OnClick" runat="server" Text="Button"></asp:Button>
		<hr />
		<asp:Label id="lblText1" runat="server"></asp:Label><br />
		<asp:Label id="lblText2" runat="server"></asp:Label><br />
		<asp:Label id="lblText3" runat="server"></asp:Label><br />
		<asp:Label id="lblText4" runat="server"></asp:Label><br />
	</form>
</body>
</html>