C#

.NET

Consider using System.IO.Path.Combine() instead of string concatenation

0
9 months ago
by Solomon in

http://dotnettipoftheday.org/tips/SystemIOPathCombine.aspx

Let’s review the following code for creating a file path:

    public string GetFullPath(string fileName)
    {
        string folder = ConfigurationManager.AppSettings["MyFolder"];
        return folder + fileName;
    }

This code is prone to error. For example, when you set the folder setting, you have to remember to make sure it ends with a slash. To avoid such problems use Path.Combine() method which will ensure that the folder has ending slash:

    public string GetFullPath(string filename)
    {
        string folder = ConfigurationManager.AppSettings["MyFolder"];
        return Path.Combine(folder, filename);
    }
.NET

?? operator (C#)

0
9 months ago
by Solomon in

http://dotnettipoftheday.org/tips/double_question_mark_operator_cs.aspx

 

The ?? operator returns the left-hand operand if it is not null, or else it returns the right operand. For example:

int? x = null;

...

// y = x, unless x is null, in which case y = -1.

int y = x ?? -1;

The ?? operator also works with reference types:

//message = param, unless param is null
//in which case message = "No message"
string message = param ?? "No message";
.NET

Correct event invocation

0
9 months ago
by Solomon in

http://dotnettipoftheday.org/tips/correct-event-invocation.aspx

Be aware that if there are no subscribers a .NET event will be null. Therefore when raising the event from C# test it for null first.


    public event EventHandler SelectedNodeChanged;

    protected virtual void OnSelectedNodeChanged(object sender, EventArgs e)
    {
        //Event will be null if there are no subscribers
        if (SelectedNodeChanged != null)
        {
            SelectedNodeChanged(this, e);
        }
    }

However in multithreaded application the last subscriber can unsubscribe immediately after the null check and before the event is raised. To avoid a null reference exception make a More >

.NET

C# Tips & Tricks

0
9 months ago
by Solomon in

 

.NET

DateTimePicker – reset focus

1
1 year ago
by Solomon in ,

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
.NET

Inherit DataGridView in Windows Forms

8
2 years ago
by Solomon in

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:


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();
        }
    }
}
.NET

Decimal to Byte array (vice versa)

14
2 years ago
by Solomon in 

        /// <summary>
        /// Decimal to Bye array
        /// </summary>
        /// <param name="dec">decimal</param>
        /// <returns>byte array</returns>
        public static byte[] DecimalToBytes(Decimal dec)
        {
            using (MemoryStream stream = new MemoryStream())
            {
                using (BinaryWriter writer = new BinaryWriter(stream))
                {
                    writer.Write(dec);

                    return stream.ToArray();
                }
            }
        }

        /// <summary>
        /// Byte array to Decimal
        /// </summary>
        /// <param name="src">byte array</param>
        /// <returns>decimal</returns>
        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();
               }

           }
        }
.NET

Byte array to String (vice versa)

0
2 years ago
by Solomon in 

        /// <summary>
        /// Byte arrary to String
        /// </summary>
        /// <param name="bytes">byte array</param>
        /// <returns>string</returns>
        public static string BytesToString(byte[] bytes)
        {
            ASCIIEncoding enc = new System.Text.ASCIIEncoding();

            return enc.GetString(bytes);
        }

        /// <summary>
        /// String to Byte array
        /// </summary>
        /// <param name="str">string</param>
        /// <returns>byte array</returns>
        public static byte[] StringToBytes(string str)
        {
            ASCIIEncoding enc = new System.Text.ASCIIEncoding();

            return enc.GetBytes(str);
        }
.NET

Byte array to Integer (vice versa)

0
2 years ago
by Solomon in 

        /// <summary>
        /// Byte array to Integer
        /// </summary>
        /// <param name="bytes">byte array</param>
        /// <returns>int</returns>
        public static int BytesToInt(byte[] bytes)
        {
            return int.Parse(BytesToString(bytes).Trim());
        }

        /// <summary>
        /// Byte array to String
        /// </summary>
        /// <param name="bytes">byte array</param>
        /// <returns>string</returns>
        public static string BytesToString(byte[] bytes)
        {
            ASCIIEncoding enc = new System.Text.ASCIIEncoding();

            return enc.GetString(bytes);
        }

        /// <summary>
        /// Integer to Byte array
        /// </summary>
        /// <param name="value">int</param>
        /// <returns>byte array</returns>
        public static byte[] IntToBytes(int value)
        {
            ASCIIEncoding enc = new System.Text.ASCIIEncoding();

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

More >

.NET

Hexadecimal to Integer (vice versa)

0
2 years ago
by Solomon in 

        /// <summary>
        /// Hexa decimal to String
        /// </summary>
        /// <param name="HexString">hexa decimal string</param>
        /// <returns>int</returns>
        public static int HexToInteger(string HexString)
        {
            return int.Parse(HexString, System.Globalization.NumberStyles.HexNumber);
        }

        /// <summary>
        /// Integer to Hexa decimal string
        /// </summary>
        /// <param name="IntValue">int</param>
        /// <returns>hexa decimal string</returns>
        public static string IntegerToHex(int IntValue)
        {
            return IntValue.ToString("X");
        }
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