Solomon » C#

DateTimePicker – reset focus

Solomon — Fri, 05 Mar 2010 03:54:18 +0000

Code Snippet – C#

        private void dateTimePicker1_Enter(object sender, EventArgs e)
        {
            DateTimePickerFormat fmt = dateTimePicker1.Format;

            dateTimePicker1.Format = DateTimePickerFormat.Long;
            dateTimePicker1.Format = DateTimePickerFormat.Custom;
            dateTimePicker1.Format = fmt;
        }

Code Snippet - VB.NET


    Private Sub DateTimePicker1_Enter(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles DateTimePicker1.Enter
        Dim fmt As DateTimePickerFormat = DateTimePicker1.Format

        DateTimePicker1.Format = DateTimePickerFormat.Long
        DateTimePicker1.Format = DateTimePickerFormat.Custom
        DateTimePicker1.Format = fmt
    End Sub

Inherit DataGridView in Windows Forms

Solomon — Fri, 04 Sep 2009 17:58:16 +0000

Create a user control class DataGridViewEx and paste the code snippet given. You can use this control where you want an inherited DataGridView.

Download source code & sample:

7z file – DataGridViewInheritance.7z

Zip file – DataGridViewInheritance.zip


using System;
using System.ComponentModel;
using System.Design;
using System.Drawing;
using System.Windows.Forms;

namespace DataGridViewInheritance
{

    [Designer(typeof(System.Windows.Forms.Design.ControlDesigner))]
    public partial class DataGridViewEx : DataGridView
    {
        public DataGridViewEx()
        {
            InitializeComponent();
        }
    }
}

Decimal to Byte array (vice versa)

Solomon — Thu, 26 Feb 2009 04:13:44 +0000


        /// 
        /// Decimal to Bye array
        /// 
        /// decimal
        /// byte array
        public static byte[] DecimalToBytes(Decimal dec)
        {
            using (MemoryStream stream = new MemoryStream())
            {
                using (BinaryWriter writer = new BinaryWriter(stream))
                {
                    writer.Write(dec);

                    return stream.ToArray();
                }
            }
        }

        /// 
        /// Byte array to Decimal
        /// 
        /// byte array
        /// decimal
        public static Decimal BytesToDecimal(byte[] src)
        {
            if (src.Length == 1)
            {
                return Decimal.Parse(((char)src[0]).ToString());
            }

           using (MemoryStream stream = new MemoryStream(src))
           {
               using (BinaryReader reader = new BinaryReader(stream))
               {
                   return reader.ReadDecimal();
               }

           }
        }

Byte array to String (vice versa)

Solomon — Thu, 26 Feb 2009 04:03:16 +0000


        /// 
        /// Byte arrary to String
        /// 
        /// byte array
        /// string
        public static string BytesToString(byte[] bytes)
        {
            ASCIIEncoding enc = new System.Text.ASCIIEncoding();

            return enc.GetString(bytes);
        }

        /// 
        /// String to Byte array
        /// 
        /// string
        /// byte array
        public static byte[] StringToBytes(string str)
        {
            ASCIIEncoding enc = new System.Text.ASCIIEncoding();

            return enc.GetBytes(str);
        }

Byte array to Integer (vice versa)

Solomon — Thu, 26 Feb 2009 03:59:18 +0000


        /// 
        /// Byte array to Integer
        /// 
        /// byte array
        /// int
        public static int BytesToInt(byte[] bytes)
        {
            return int.Parse(BytesToString(bytes).Trim());
        }

        /// 
        /// Byte array to String
        /// 
        /// byte array
        /// string
        public static string BytesToString(byte[] bytes)
        {
            ASCIIEncoding enc = new System.Text.ASCIIEncoding();

            return enc.GetString(bytes);
        }

        /// 
        /// Integer to Byte array
        /// 
        /// int
        /// byte array
        public static byte[] IntToBytes(int value)
        {
            ASCIIEncoding enc = new System.Text.ASCIIEncoding();

            return enc.GetBytes(value.ToString());
        }

        /// 
        /// Bytes to Integer
        /// 
        /// 
        /// 
        public static int BytesToInt(byte[] src)
        {
             if (src.Length == 1)
                 return (int)src[0];
             else if (src.Length <= 2)
                 return BitConverter.ToInt16(src, 0);

             return BitConverter.ToInt32(src, 0);
         }

Hexadecimal to Integer (vice versa)

Solomon — Thu, 26 Feb 2009 03:54:36 +0000


        /// 
        /// Hexa decimal to String
        /// 
        /// hexa decimal string
        /// int
        public static int HexToInteger(string HexString)
        {
            return int.Parse(HexString, System.Globalization.NumberStyles.HexNumber);
        }

        /// 
        /// Integer to Hexa decimal string
        /// 
        /// int
        /// hexa decimal string
        public static string IntegerToHex(int IntValue)
        {
            return IntValue.ToString("X");
        }

Hexadecimal string to Bytes array

Solomon — Thu, 26 Feb 2009 03:51:01 +0000


        /// 
        /// Hexa decimal to Byte array
        /// 
        /// Hexa decimal string
        /// byte array
        public static byte[] HexToBytes(String hexString)
        {
            byte[] byteArray = null;
            int byteCount = 0;

            if (hexString != null && hexString.Length > 0)
            {
                // make sure we have an even number of characters
                if (hexString.Length % 2 != 0)
                    hexString = "0" + hexString;

                byteCount = hexString.Length / 2;
                byteArray = new byte[byteCount];
                string sTemp;

                for (int i = 0; i < byteCount; i++)
                {
                    sTemp = hexString.Substring(i * 2, 2);
                    byteArray[i] = Convert.ToByte(sTemp, 16);
                }
            }

            return byteArray;
        }

Bytes array to Hexadecimal string

Solomon — Thu, 26 Feb 2009 03:47:15 +0000


        /// 
        /// Byte array to Hexa decimal string
        /// 
        /// byte array
        /// hexa decimal string
        public static string BytesToHex(byte[] bytes)
        {
            string hex = BitConverter.ToString(bytes);

            return hex.Replace("-", "");
        }

        /// 
        /// Byte array to Hexa decimal string
        /// 
        /// byte array
        /// bool include hyphen
        /// hexa decimal string
        public static string BytesToHex(byte[] bytes, bool includeHyphen)
        {
            string hex = BitConverter.ToString(bytes);

            return hex;
        }

Auto Complete ComboBox – C# Windows Forms

Solomon — Tue, 24 Feb 2009 04:38:37 +0000

Introduction

This is a simple code snippet which is used to make an Auto Complete ComboBox.

Using the code

Usage: Call the function AutoComplete from within the ComboBox’s KeyPress event handler.


AutoComplete(ComboBox cb, System.Windows.Forms.KeyPressEventArgs e, bool blnLimitToList)

Code


        /// 
        /// AutoComplete
        /// 
        /// ComboBox
        /// KeyPressEventArgs
        /// Limit to List
		public void AutoComplete(ComboBox cb, System.Windows.Forms.KeyPressEventArgs e, bool blnLimitToList)
		{
			string strFindStr = "";

			if (e.KeyChar == (char)8)
			{
				if (cb.SelectionStart <= 1)
				{
					cb.Text = "";
					return;
				}

				if (cb.SelectionLength == 0)
					strFindStr = cb.Text.Substring(0, cb.Text.Length - 1);
						else
					strFindStr = cb.Text.Substring(0, cb.SelectionStart - 1);
					}
			else
			{
				if (cb.SelectionLength == 0)
					strFindStr = cb.Text + e.KeyChar;
				else
					strFindStr = cb.Text.Substring(0, cb.SelectionStart) + e.KeyChar;
			}

			int intIdx = -1;

			// Search the string in the ComboBox list.

			intIdx = cb.FindString(strFindStr);

			if (intIdx != -1)
			{
				cb.SelectedText = "";
				cb.SelectedIndex = intIdx;
				cb.SelectionStart = strFindStr.Length;
				cb.SelectionLength = cb.Text.Length;
				e.Handled = true;
			}
			else
			{
				e.Handled = blnLimitToList;
			}
		}

History

Released on November 8th 2006.

DataGrid Paging using DataReader – C# Windows Forms

Solomon — Tue, 24 Feb 2009 04:36:48 +0000

Introduction

This is an example of Windows Forms DataGrid paging using c#. I have used Microsoft SQL Server 2000 database.

Using the code

Create a table:


create table tblEmp
    (
      E_ID int primary key ,
      E_Name varchar(60) ,
      E_Salary money ,
      E_DOJ datetime
    )
go

Public variables:


		/// 
		/// Required designer variable.
		/// 

		// Protected Connection.
		protected SqlConnection mcnSample;

		// Page
		private int mintTotalRecords = 0;
		private int mintPageSize = 0;
		private int mintPageCount = 0;
		private int mintCurrentPage = 1;

		// Connection String
		protected const string CONNECTION_STRING = "Server=localhost;UID=sa;PWD=;Database=Sample";

fillGrid() method:


		private void fillGrid()
		{
			// For Page view.
			this.mintPageSize = int.Parse(this.tbPageSize.Text);
			this.mintTotalRecords = getCount();
			this.mintPageCount = this.mintTotalRecords / this.mintPageSize;

			// Adjust page count if the last page contains partial page.
			if (this.mintTotalRecords % this.mintPageSize > 0)
				this.mintPageCount++;

			this.mintCurrentPage = 0;

			loadPage();
		}

getCount() method: This method gets the record count much faster than SELECT COUNT(*) statement.


		private int getCount()
		{
			// This select statement is very fast compare to SELECT COUNT(*)
			string strSql = "SELECT Rows FROM SYSINDEXES WHERE Id = OBJECT_ID('tblEmp') AND IndId < 2";
			int intCount = 0;

			SqlCommand cmd = this.mcnSample.CreateCommand();
			cmd.CommandText = strSql;

			intCount = (int) cmd.ExecuteScalar();
			cmd.Dispose();

			return intCount;
		}

loadPage() method:


		private void loadPage()
		{
			string strSql = "";
			int intSkip = 0, i = 0;
			SqlDataReader dr;
			DataSet ds;
			DataTable dt;

			intSkip = (this.mintCurrentPage * this.mintPageSize);

			strSql = "SELECT * FROM tblEmp";

			SqlCommand cmd = this.mcnSample.CreateCommand();
			cmd.CommandText = strSql;

			dr = cmd.ExecuteReader();
			ds = new DataSet();

			dt = ds.Tables.Add("tblEmp");

			// Add the table columns.
			for (i = 0; i < dr.FieldCount; i++)
				dt.Columns.Add(dr.GetName(i), dr.GetFieldType(i)); 

			int intIdx = 0;
			while (dr.Read())
			{
				if (intIdx >= intSkip)
				{
					DataRow r = dt.NewRow();

					// Assign DataReader values to DataRow.
					for (i = 0; i < dr.FieldCount; i++)
						r[i] = dr[i];

					dt.Rows.Add(r);
				}

				if ((intIdx - intSkip) >= (this.mintPageSize - 1))
					break;

				intIdx++;
			}

			dr.Close();

			// Populate Data Grid
			this.dgEmp.DataSource = ds.Tables["tblEmp"].DefaultView;

			// Show Status
			this.lblStatus.Text = (this.mintCurrentPage + 1).ToString() + " / " + this.mintPageCount.ToString();

			cmd.Dispose();
			ds.Dispose();
		}

For page navigation:


		private void goFirst()
		{
			this.mintCurrentPage = 0;

			loadPage();
		}

		private void goPrevious()
		{
			if (this.mintCurrentPage == this.mintPageCount)
				this.mintCurrentPage = this.mintPageCount - 1;

			this.mintCurrentPage--;

			if (this.mintCurrentPage < 1)
				this.mintCurrentPage = 0;

			loadPage();
		}

		private void goNext()
		{
			this.mintCurrentPage++;

			if (this.mintCurrentPage > (this.mintPageCount - 1))
				this.mintCurrentPage = this.mintPageCount - 1;

			loadPage();
		}

		private void goLast()
		{
			this.mintCurrentPage = this.mintPageCount - 1;

			loadPage();
		}

History

Released on November 9th 2006.