Search This Blog

Friday, March 28, 2014

ASP.NET System Web UI HtmlControls

ASP.NET > System.Web.UI.HtmlControls

Contains classes that allow you to create HTML server controls on a Web Forms page, so it allows you to programmatically control the HTML elements on a Web Forms page.





Create dynamic table runtime ASP.NET

ASP.NET > System.Web.UI.HtmlControls > HtmlTable 

HtmlTable allows programmatic access on the server to the HTML
element.


Example: Create dynamic table runtime ASP.NET

HTML:

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="WebApplication2.WebForm1" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
   
        <asp:Panel ID="Panel1" runat="server">
        </asp:Panel>
   
    </div>
    </form>
</body>
</html>






Code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;

namespace WebApplication2
{
    public partial class WebForm1 : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            HtmlTable dTable = new HtmlTable();
            dTable.Border = 1;
            int tRow; 
            int tCell; 
            for (tRow = 0; tRow < 10; tRow++) 
            { 
                HtmlTableRow dTRow = new HtmlTableRow(); 
                for (tCell = 0; tCell < 5; tCell++) 
                { 
                    HtmlTableCell dTCell = new HtmlTableCell(); 
                    dTCell.InnerText = "Row: " + Convert.ToString(tRow + 1) + " Col: " + Convert.ToString(tCell + 1); 
                    dTRow.Controls.Add(dTCell); 
                } 
                dTable.Controls.Add(dTRow); 
            } 
            Panel1.Controls.Add(dTable); 

        }
    }
}




C# Keywords

C# > Keywords

Keywords are reserved identifiers used by compiler. 


  • cannot be used as identifiers in your program unless they include @ as a prefix (@then is a valid identifier)
  • contextual keywords have special meaning only in a limited program context and can be used as identifiers outside that context
Literal keywords
    Access keywords
      Access modifiers
      Operator
        Method
        Contextual









        Null keyword C#

        C# > Keywords > Null

        Null represent reference that does not refer to any object.
        • default value of reference type variables
        • ordinary value types cannot be null

        Example

        using System;
        using System.Collections.Generic;
        using System.ComponentModel;
        using System.Data;
        using System.Drawing;
        using System.Linq;
        using System.Text;
        using System.Threading.Tasks;
        using System.Windows.Forms;

        namespace WindowsFormsApplication2
        {
            public class TestClass
            {
                public void TestMethod() { }
            }

            public partial class Form1 : Form
            {
                public Form1()
                {
                    InitializeComponent();
                }

                private void Form1_Load(object sender, EventArgs e)
                {
                   
                    TestClass tc=null;

                    tc = new TestClass();
                    tc.TestMethod();   // You can call TestMethod method.

                    tc = null; // set tc to null => the object is no longer accessible and can now be garbage collected
                   
                    string s1 = null;

                    //int k = null; // Error Cannot convert null to 'int' because it is a non-nullable value type  

                    int? k = null; // use a nullable value type instead OK

                }
            }
        }










        Tuesday, March 25, 2014

        Filter with LINQ DataTable C#

        C# > System.Data   > DataTable > Filter with LINQ

        Example:


        DataTable dt = new DataTable("table");
        dt.Columns.Add("id", Type.GetType("System.Int32"));
        dt.Columns.Add("name", Type.GetType("System.String"));

        DataRow dr = dt.NewRow();
        dr["id"] = 1;
        dr["name"] = "john";
        dt.Rows.Add(dr);

        dr = dt.NewRow();
        dr["id"] = 2;
        dr["name"] = "dan";
        dt.Rows.Add(dr);

        DataTable tbl = (from DataRow dr1 in dt.Rows
                             where dr1["id"].ToString() == "1"
                             select dr).CopyToDataTable();





        Friday, March 21, 2014

        DateValue Visual Basic Example

        VB.NET Functions > DateValue 

        Returns a date value containing the date information represented by a string.

        Example

        Dim dt As Date
        dt = DateValue("March 21, 2014")

        MessageBox.Show(dt)






        Oracle Sequence Example

        OracleSequence

        Sequences are database objects from which multiple users can generate unique integers. The sequence generator generates sequential numbers, which can help to generate unique primary keys automatically, and to coordinate keys across multiple rows or tables.


        Example:

        CREATE SEQUENCE order_sequence
              INCREMENT BY 1
              START WITH 1
              NOMAXVALUE
              NOCYCLE
              CACHE 10;

        INSERT INTO orders (order_no)
        VALUES (order_sequence.NEXTVAL);





        Wednesday, March 19, 2014

        Var C# Example

        C#Types > Var

        Var is implicitly typed.

        An implicitly typed local variable is strongly typed, but 

        the compiler determines the type. 


        Example


        // var is required because the select clause specifies an anonymous type 

        var query = from prod in products
                    where prod.Category == "shoes"
                    select new { prod.Name, prod.Price };

        // var is required because item is an anonymous type
        foreach (var item in query)
        {
                       

        }




        C# Void Type Example

        C# > Types > Void

        Void specifies that the method doesn't return a value.

        Example


        private void Log(string msg)
        {
           // log method

        }






        SQL Server Drop

        SQL Server > DDL > Drop

        DROP statements removes existing entities.




        DateDiff Visual Basic Example

        VB.NET Functions > DateDiff

        Returns a value specifying the number of time intervals 
        between two dates.

        Example:


        Dim dt1 As Date = #3/1/2014#
        Dim dt2 As Date = #4/1/2014#

        MessageBox.Show("Day diff: " & DateDiff(DateInterval.Day, dt1, dt2) & " Week diff: " & DateDiff(DateInterval.Weekday, dt1, dt2))