DataTypes - C#.NET

Primary Data Types:
   1. Integer Number 
     a. byte,sbyte
     b. short, ushort
     c. int ,uint
     d. long, ulong

   2. Real Number/Floating point 
      a. float
      b. double
      c. decimal

   3. String/Text
   4. Boolean
   5. Character

Custom Data Type: 
  a. class
  b. struct
  ...

Mohammad Towhidul Islam

03-Aug-22 05:19:18 pm

virtual and override keyword in C# for implementing Polymorphism

The virtual keyword is used to modify a method, property, indexer, or event declaration and allow for it to be overridden in a derived class. For example, this method can be overridden by any class that inherits it:
 
class TestClass
{
    public class Shape
    {
        public const double PI =...

Mohammad Towhidul Islam

14-Mar-22 04:51:07 pm

How to calculate sum of a DataTable's Column in LINQ?

If untyped (replace int with the correct data type):
 
var sum = table.AsEnumerable().Sum(x=>x.Field<int>(3));
 
or
 
var sum = table.AsEnumerable().Sum(x=>x.Field<int>("SomeProperty"));
 
If typed:
 
 var sum = table.Sum(x=>x.SomeProperty);
 ...

Mohammad Towhidul Islam

28-Aug-21 08:38:59 pm

Anonymous Types in C#

Anonymous type: 
 
  var v = new { Amount = 108, Message = "Hello" };
 Console.WriteLine(v.Amount + v.Message);
 
 Array of anonymous type: 
 
var anonArray = new[] { new { name = "apple", diam = 4 }, new { name = "grape", diam = 1 }};
 
 Nested anonymous type: 
 ...

Mohammad Towhidul Islam

20-Nov-20 02:03:10 am

Stringify json in C# ASP.net core

Method 1

using System.Web.Script.Serialization;
 
  var json = new JavaScriptSerializer().Serialize(new {name='jahid',age=24});
 
Method 2

using Newtonsoft.Json;
 
var json=JsonConvert.SerializeObject(new {name='jahid',age=24});
 ...

Mohammad Towhidul Islam

09-Oct-16 01:23:57 pm

DataView RowFilter Syntax [C#]

This example describes syntax of DataView.RowFil­ter expression. It shows how to correctly build expression string (without „SQL injection“) using methods to escape values.

 Column names 
If a column name contains any of these special characters ~ ( ) #  / = > < + - * % & | ^ ' "...

Mohammad Towhidul Islam

02-Sep-16 11:09:10 am

Parameters to Queries by SqlCommand

using System;
using System.Data;
using System.Data.SqlClient;

class ParamDemo
{
	static void Main()
	{
		// conn and reader declared outside try
		// block for visibility in finally block
		SqlConnection conn   = null;
		SqlDataReader reader = null;

		string inputCity = "Londo...

Mohammad Towhidul Islam

21-Aug-16 06:54:43 pm

DataTable and LINQ

Example 1
 
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace DataTableLinq
{
    public partial class Form1 : Form
    {
        public Form1()
        {
...

Mohammad Towhidul Islam

07-Jul-15 12:22:32 pm

Consume WCF calculator service by winform

using CalClient.CalService;
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 CalClient
{
    public partial...

Mohammad Towhidul Islam

07-Jul-15 11:54:09 am

DisplayMember and ValueMember Attribute in ComboBox

DataTable table = new DataTable();
table.Columns.Add("operator", typeof(string));
table.Columns.Add("name", typeof(string));
        
// Here we add five DataRows.
table.Rows.Add("+", "Sum");
table.Rows.Add("-", "Subtract");
tabl...

First Prev 1 2 3 Next Last

1 of 3 pages