How to Display Line Numbers in Visual Studio

Show Line Numbers in Visual Studio

It is always better to have Line numbers displayed in Visual Studio when you debug your VB or C# Project. It is not turned on by default. you can turn it on as shown below

Cint Function in VB.NET / Convert String to Integer in VB.NET

Following snippet provides a hint for Converting an Integer to String

        Dim i1 As Integer

        Integer.TryParse("13", i1)

        MessageBox.Show(i1.ToString())

Abstract Classes in VB.NET

Abstract classes are base classes that has to be inherited.  A class can be made as an abstract with MustInherit modifier

Abstract classes can contain abstract methods also. Abstract methods are the ones where only signature is available in the base class and their implementation is taken care in derived classes.

Following is an example of abstract class:

Public MustInherit Class ClassAbs



    Public Sub ExampleMethod()

        MessageBox.Show("This is sample")

    End Sub

    Public MustOverride Sub ExampleMethod_ShouldBeInherited()



    Public Overridable Sub ExampleMethod_CanBeCalledFromBase()

        MessageBox.Show("This is sample")

    End Sub

End Class

the class contains one Abstract method

The class can be inherited as shown below:

Public Class ClassDerivedFromAbstract
    Inherits ClassAbs

    Public Sub ExampleAbstract()

        MyBase.ExampleMethod_CanBeCalledFromBase()


    End Sub

    Public Overrides Sub ExampleMethod_ShouldBeInherited()


    End Sub

    Public Overrides Sub ExampleMethod_CanBeCalledFromBase()

        MessageBox.Show("This is sample from Derived")

    End Sub

End Class

The class can be used as shown below:

Dim CAb As New ClassDerivedFromAbstract

        CAb.ExampleMethod_CanBeCalledFromBase()
        CAb.ExampleMethod_ShouldBeInherited()

the first call uses the method from the base class and the second one uses the Method we had overriden in the derived class

How to make Windows Form fit FullScreen using VB.NET

We have already seen How to Get Width and Height of Desktop Screen using C#/VB.NET in previous post. The following VB.NET snippet provides a method to make the Windows Form fir the Desktop screen

Dim iWidth As Integer = Screen.PrimaryScreen.Bounds.Width
        Dim iHeight As Integer = Screen.PrimaryScreen.Bounds.Height

        Me.Width = iWidth
        Me.Height = iHeight

        Me.Location = New System.Drawing.Point(0, 0)

You can add this snippet in Form_Load sub

Video Tutorial - Add a new button on Office backstage using C#

How to add a new button to Office (Excel) Backstage from Addin using VSTO (C#)

The following XML adds a new button on Backstage. The button will be added at the end as we didn't specify a location.

What is a Backstage view and How to customize it?

Backstage view in Office 2010 - An Introduction

Backstage was introducted in Office 2010 to hold commands and menus which are do some work 'on the document', for example, Printing, Publishing to SharePoint etc.

Backstage view is part of Office Fluent UI and very much customizable. The following video shows the elements of Backstage view.

Office 2010 BackStage View - An Introduction to customizable elements

How to Get Width and Height of Desktop Screen using C#/VB.NET

How to resize Windows form to fit Windows screen using C#/VB.NET

The following code resizes the Form Window to fit the entire screen .

int iWindowWidth = Screen.PrimaryScreen.Bounds.Width;
            int iWindowHeight = Screen.PrimaryScreen.Bounds.Height;
            this.Size = new Size(iWindowWidth, iWindowHeight ) ;

How to Enable a Disabled VSTO Addin

VSTO Addin is not getting Executed / VSTO Addin Stopped working

If your VSTO addin stopped working suddenly, it might because the Application would have taken precautionary measure by disabling your Addin.

The disabled addins can be checked from Excel/Word options from Backstage View as shown below:

Select the Addin you want to enable and select Enable:

How to Add Images to Project Resources in C#/.NET

How to add/deploy Images in C#/.NET (Visual Studio)

You can add images as resources to the project. The images will be stored as part of your solution and get deployed when you deploy your solution. To add an image to the project, select Resources Tab from Project Properties and click on Add Resources; Select an appropriate file

Resources Tab in Visual Studio

Once the image is added it will be displayed as shown below:

Image added as Resource to C#/VB.NET Project

The resource file is part of your project as shown below:

Accessing Resource through C#/VB.NET Code

To access the image from code use the following

public System.Drawing.Bitmap GetButtonImage(Office.IRibbonControl control)
        {
            switch(control.Id)
            {
                case "btnmoscow":
                    return Properties.Resources.moscow;
.
.
,
                default:
                    return null;

            }           

        }

C#/VB.NET Excel Autofilter - Specify Multiple Criteria using Array

C#/VB.NET Excel Autofilter - Only Last Value is Displayed

Here is a simple example of Filtering ListObjects using Excel AutoFilter function. This example uses the following spreadsheet

The following C# code will filter 'Apple' and 'Orange' using an Array

private void ExcelFilterExample()
        {
            String[] FilterList = {"Apple","Orange"};
            Excel.Workbook oWB = Globals.ThisAddIn.Application.Workbooks.Open(@"C:\Users\comp\Documents\FreshFruitsnVegetables.xls");
            Excel.Worksheet oWS = oWB.Worksheets[1];
            oWS.ListObjects.AddEx (Excel.XlListObjectSourceType.xlSrcRange, oWS.UsedRange, System.Type.Missing  ,Excel.XlYesNoGuess.xlYes).Name = "FruitList"; 
            oWS.ListObjects["FruitList"].Range.AutoFilter(2, FilterList, Excel.XlAutoFilterOperator.xlFilterValues   );
        }

VB.NET Excel Offset Function / C# Excel Offset Function

How to Offset Excel Ranges using VB.NET / C#

The following code gives you a better insight into offsetting a range using C#. The code uses get_Offset method to Offset the range

private void MathTableExample()
        {
            Microsoft.Office.Interop.Excel.Range oRng;
            oRng = Globals.ThisAddIn.Application.get_Range("A1");

            for (int i = 1; i <= 10; i++)
            {
                // Uses Offset Method of Excel     
                oRng.get_Offset(i, 0).Value2 = "9 x " + i.ToString() + " = " + (i * 9).ToString();
            }


        }

How to disable/suppress Addin Errors in Excel/ Word

Disable/suppress Addin Errors while loading in Excel/ Word (VSTO/.NET)

If you don't want to show your users the following kind of embarrassing errors:

Use the following option from Excel/Word Options --> Advanced

Disable Errors while Loading

NOT Operator in C# (.NET)

What is the equivalent for VB NOT operator in C#

VB Programmers use NOT operator often. For example,


If Not Range is nothing


or


FlagDone = Not Failed



You can do the same in C# as shown below:

Microsoft.Office.Interop.Excel.Range oRng;

            oRng = null;
            if (object.ReferenceEquals(oRng,null)) 
            {
                oRng = null;
            }

and also in the following context to toggle the Button and TaskPane

Globals.Ribbons.RibbonFB.button1.Enabled  =(!CusPane.Visible);

How to make .NET application compatible to all platforms 32 bit and 64 bit

How to convert a 32 bit .NET application to 64 bit

If you have developed application for 32 bit and want to make the application work in all platforms, change the Platform target to all from Project properties

Platform Compatibility (32 bit, 64 bit) for .NET application

How to Display WebPage Title on Windows Form using C#/.NET

Change Windows Form Caption dynamically using C#/VB.NET to display WebPage Title

It is good to display Webpage title on the userform  or any other control that hosts Webbrowser. This ressembles the functionaliy of Internet Explorer. The following code does the same:

private void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
        {

            this.Text = webBrowser1.Document.Title;
        }

Webpage On UserForm - Title

The code uses DocumentCompleted event to update the WinForm's caption.

How to Browse WebPages using WinForm

How to use WebControl in Windows Forms

WebBrowser control can be used to display Webpages on userform. Add a webbrowser control to the userform

WebBrowser Control and Userform

Default page can be set used the URL property. Here I have set URL property to bing.com


WebBrowser Control and Userform

The same can be set through code using:

webBrowser1.Navigate("http://www.bing.com");

C# Color Code and RGB Values / VB.NET Color Code and RGB Values

Color Name	RGB Value
RGB Value of  AliceBlue	#F0F8FF
RGB Value of  AntiqueWhite	#FAEBD7
RGB Value of  Aqua	#00FFFF
RGB Value of  Aquamarine	#7FFFD4
RGB Value of  Azure	#F0FFFF
RGB Value of  Beige	#F5F5DC
RGB Value of  Bisque	#FFE4C4
RGB Value of  Black	#000000
RGB Value of  BlanchedAlmond	#FFEBCD
RGB Value of  Blue	#0000FF
RGB Value of  BlueViolet	#8A2BE2
RGB Value of  Brown	#A52A2A
RGB Value of  BurlyWood	#DEB887
RGB Value of  CadetBlue	#5F9EA0
RGB Value of  Chartreuse	#7FFF00
RGB Value of  Chocolate	#D2691E
RGB Value of  Coral	#FF7F50
RGB Value of  CornflowerBlue	#6495ED
RGB Value of  Cornsilk	#FFF8DC
RGB Value of  Crimson	#DC143C
RGB Value of  Cyan	#00FFFF
RGB Value of  DarkBlue	#00008B
RGB Value of  DarkCyan	#008B8B
RGB Value of  DarkGoldenrod	#B8860B
RGB Value of  DarkGray / DarkGrey†	#A9A9A9
RGB Value of  DarkGreen	#006400
RGB Value of  DarkKhaki	#BDB76B
RGB Value of  DarkMagenta	#8B008B
RGB Value of  DarkOliveGreen	#556B2F
RGB Value of  DarkOrange	#FF8C00
RGB Value of  DarkOrchid	#9932CC
RGB Value of  DarkRed	#8B0000
RGB Value of  DarkSalmon	#E9967A
RGB Value of  DarkSeaGreen	#8FBC8F
RGB Value of  DarkSlateBlue	#483D8B
RGB Value of  DarkSlateGray / DarkSlateGrey†	#2F4F4F
RGB Value of  DarkTurquoise	#00CED1
RGB Value of  DarkViolet	#9400D3
RGB Value of  DeepPink	#FF1493
RGB Value of  DeepSkyBlue	#00BFFF
RGB Value of  DimGray / DimGrey†	#696969
RGB Value of  DodgerBlue	#1E90FF
RGB Value of  FireBrick	#B22222
RGB Value of  FloralWhite	#FFFAF0
RGB Value of  ForestGreen	#228B22
RGB Value of  Fuchsia	#FF00FF
RGB Value of  Gainsboro	#DCDCDC
RGB Value of  GhostWhite	#F8F8FF
RGB Value of  Gold	#FFD700
RGB Value of  Goldenrod	#DAA520
RGB Value of  Gray / Grey†	#808080
RGB Value of  Green	#008000
RGB Value of  GreenYellow	#ADFF2F
RGB Value of  Honeydew	#F0FFF0
RGB Value of  HotPink	#FF69B4
RGB Value of  IndianRed	#CD5C5C
RGB Value of  Indigo	#4B0082
RGB Value of  Ivory	#FFFFF0
RGB Value of  Khaki	#F0E68C
RGB Value of  Lavender	#E6E6FA
RGB Value of  LavenderBlush	#FFF0F5
RGB Value of  LawnGreen	#7CFC00
RGB Value of  LemonChiffon	#FFFACD
RGB Value of  LightBlue	#ADD8E6
RGB Value of  LightCoral	#F08080
RGB Value of  LightCyan	#E0FFFF
RGB Value of  LightGoldenrodYellow	#FAFAD2
RGB Value of  LightGreen	#90EE90
RGB Value of  LightGray† / LightGrey	#D3D3D3
RGB Value of  LightPink	#FFB6C1
RGB Value of  LightSalmon	#FFA07A
RGB Value of  LightSeaGreen	#20B2AA
RGB Value of  LightSkyBlue	#87CEFA
RGB Value of  LightSlateGray / LightSlateGrey†	#778899
RGB Value of  LightSteelBlue	#B0C4DE
RGB Value of  LightYellow	#FFFFE0
RGB Value of  Lime	#00FF00
RGB Value of  LimeGreen	#32CD32
RGB Value of  Linen	#FAF0E6
RGB Value of  Magenta	#FF00FF
RGB Value of  Maroon	#800000
RGB Value of  MediumAquamarine	#66CDAA
RGB Value of  MediumBlue	#0000CD
RGB Value of  MediumOrchid	#BA55D3
RGB Value of  MediumPurple	#9370DB
RGB Value of  MediumSeaGreen	#3CB371
RGB Value of  MediumSlateBlue	#7B68EE
RGB Value of  MediumSpringGreen	#00FA9A
RGB Value of  MediumTurquoise	#48D1CC
RGB Value of  MediumVioletRed	#C71585
RGB Value of  MidnightBlue	#191970
RGB Value of  MintCream	#F5FFFA
RGB Value of  MistyRose	#FFE4E1
RGB Value of  Moccasin	#FFE4B5
RGB Value of  NavajoWhite	#FFDEAD
RGB Value of  Navy	#000080
RGB Value of  OldLace	#FDF5E6
RGB Value of  Olive	#808000
RGB Value of  OliveDrab	#6B8E23
RGB Value of  Orange	#FFA500
RGB Value of  OrangeRed	#FF4500
RGB Value of  Orchid	#DA70D6
RGB Value of  PaleGoldenrod	#EEE8AA
RGB Value of  PaleGreen	#98FB98
RGB Value of  PaleTurquoise	#AFEEEE
RGB Value of  PaleVioletRed	#DB7093
RGB Value of  PapayaWhip	#FFEFD5
RGB Value of  PeachPuff	#FFDAB9
RGB Value of  Peru	#CD853F
RGB Value of  Pink	#FFC0CB
RGB Value of  Plum	#DDA0DD
RGB Value of  PowderBlue	#B0E0E6
RGB Value of  Purple	#800080
RGB Value of  Red	#FF0000
RGB Value of  RosyBrown	#BC8F8F
RGB Value of  RoyalBlue	#4169E1
RGB Value of  SaddleBrown	#8B4513
RGB Value of  Salmon	#FA8072
RGB Value of  SandyBrown	#F4A460
RGB Value of  SeaGreen	#2E8B57
RGB Value of  Seashell	#FFF5EE
RGB Value of  Sienna	#A0522D
RGB Value of  Silver	#C0C0C0
RGB Value of  SkyBlue	#87CEEB
RGB Value of  SlateBlue	#6A5ACD
RGB Value of  SlateGray / SlateGrey†	#708090
RGB Value of  Snow	#FFFAFA
RGB Value of  SpringGreen	#00FF7F
RGB Value of  SteelBlue	#4682B4
RGB Value of  Tan	#D2B48C
RGB Value of  Teal	#008080
RGB Value of  Thistle	#D8BFD8
RGB Value of  Tomato	#FF6347
RGB Value of  Turquoise	#40E0D0
RGB Value of  Violet	#EE82EE
RGB Value of  Wheat	#F5DEB3
RGB Value of  White	#FFFFFF
RGB Value of  WhiteSmoke	#F5F5F5
RGB Value of  Yellow	#FFFF00
RGB Value of  YellowGreen	#9ACD32

Event Handler to Handle Multiple Events (C#/.NET)

Event handlers are of great use especially in WinForms programming. There might be a case where you will be having multiple Objects (Buttons for example), which requires to fire events of same type

The following snippet shows how to declare an eventhandler and assign it to multiple events

private void btn_Click(object sender, EventArgs e)
        {
            Button b1;
            b1 =  (System.Windows.Forms.Button)sender;
            MessageBox.Show("Button Clicked := " + b1.Name.ToString());
            b1.ForeColor = Color.Red;
        }

The above event handler is a generic one. It contains two arguments the sender, which contains the object that fired the event and Arguments.

Statement
b1 = (System.Windows.Forms.Button)sender;

Assigns (or casts) the object to button object. If casting is not done Cannot implicitly convert type 'object' to 'System.Windows.Forms.Button'. An explicit conversion exists (are you missing a cast?) is thrown

The snippet below assigns the sub - btn_Click with click events of both buttons

button1.Click += new EventHandler(btn_Click); 
           button2.Click += new EventHandler(btn_Click);

Could not find type 'WindowsFormsControlLibrary1.UserControl1

Could not find type 'WindowsFormsControlLibrary1.UserControl1'. Please make sure that the assembly that contains this type is referenced. If this type is a part of your development project, make sure that the project has been successfully built using settings for your current platform or Any CPU.

What is solution for - "Visual Studio has encountered an exception. This may be caused by an extension."

---------------------------
Microsoft Visual Studio
---------------------------
Visual Studio has encountered an exception. This may be caused by an extension.



You can get more information by running the application together with the /log parameter on the command line, and then examining the file 'C:\Users\comp\AppData\Roaming\Microsoft\VisualStudio\10.0\ActivityLog.xml'.

User Controls not showing up in the toolbox / New usercontrol not appearing in toolbox

User Control Will Not Appear In Toolbox / User Control not listed in toolbox


Here is a method to add UserControl manually to the toolbox:

Step 1: Right Click on ToolBox and select Choose Items

Step 2: Choose the ToolBox items you want to display. If your Usercontrol is not listed in Toolbox then Browse for the DLL and enable the checkbox

How to make ActiveX control to interact with COM Object

How to make ActiveX control to expose COM Object

The Register for COM interop Checkbox indicates that your managed application will expose a COM object (a COM callable wrapper) that allows a COM object to interact with your managed application.

The Output type property in the Application page of the Project Designer for this application must be set to Class Library in order for the Register for COM interop property to be available.

How to format Currency (Pound/Dollar/Euro etc) using C#/VB.NET/Csharp Writeline function

Formatting Currency in C#/VB.NET/Csharp Writeline function

You can use .NET's Composite Formatting to format the currency as shown below

    Double Incentive = 234.45;
            Console.WriteLine("The agreed incentive in local currency is {0:C} ", Incentive);
        

If you want to convert it into dollars/pounds etc you need to change the culture info :

            Thread.CurrentThread.CurrentCulture = new CultureInfo("en-US", false);
            Console.WriteLine("The agreed incentive in USD is {0:C} ", Incentive);


            Thread.CurrentThread.CurrentCulture = new CultureInfo("en-GB", false);
            Console.WriteLine("The agreed incentive in GBP is {0:C} ", Incentive);

The above code needs the following directives

using System.Threading;
using System.Globalization;

en-UK is an invalid culture identifier - VB.NET/C#/Csharp

Culture is not supported. Parameter name: name en-UK is an invalid culture identifier.

en-UK is an invalid culture identifier - VB.NET/C#/Csharp

We are used to en-UK as culture. but for some reasons MS doesn't support en-UK (UK is used for Ukraine)

Hence replace

Thread.CurrentThread.CurrentCulture = new CultureInfo("en-UK", false);
            

with

Thread.CurrentThread.CurrentCulture = new CultureInfo("en-GB", false);
            

How to pass an argument by reference in Csharp/C#/VB.NET

Pass by Reference/Pass by Value in VB.NET/C-Sharp/C#

Here is an example of passing an argument to a function by Value:

private static void PassByValueExample(double Salary)//
        {
            Salary = Salary * 1.2;
        }

Here is how it is passed as reference

private static void PassByRefExample(ref double Salary)//
        {
            Salary = Salary * 1.2;
        }

The following code shows the difference between the two

Console.WriteLine("Salary before hike is {0:F}", Sal);
            PassByValueExample( Sal);
            Console.WriteLine("Salary after hike is {0:F}", Sal);

            Console.WriteLine("Salary before hike is {0:F}", Sal);
            PassByRefExample(ref Sal);
            Console.WriteLine("Salary after hike is {0:F}", Sal);

See also:

Output Parameters in C# (.NET)

How to get the return value from C# program (console application)

Object Arrays in C# using Indexers

 

 

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Input string was not in a correct format. - Csharp/VB.NET WriteLine Function

If you are using VB.NET/C# Writeline function and facing the following error, it has to do with formatting

Input string was not in a correct format. - Csharp/VB.NET

Wrong :

double Sal = 1250.45;
        Console.WriteLine("Salary before hike is {0:D}", Sal); //Decimal instead of double
        Console.WriteLine("Salary before hike is {F}", Sal); //Index is missing
            

Correct:

double Sal = 1250.45;
        
Console.WriteLine("Salary before hike is {0:F}", Sal);

USe appropriate composite format string - decimal , double

How to pass Database Field Name to SQLDataReader GetString Function

How to retrieve data from SQLDataReader using FieldNames in C# (.NET)

It is always better practice to use Field names instead of Index. You can decide which of the following is clear

string sPlayerName =  rdr[1].ToString();
             sPlayerName = rdr["PlayerFirstName"].ToString();

The best overloaded method match for 'System.Data.Common.DbDataReader.GetString(int)' has some invalid arguments

Parametrized Query in C# / .NET

How to pass parameters in SQL Queries in .NET (C#)

Parametrized queries are more secure (avoids SQL Injection etc) and easy to handle. The following example shows an simple example.

Parametized Query - Sample Table

The above table has details of Players like name, contact details etc.

Let us try to get the details of players whose first name is 'Sachin'. First make a connection to database :

string sConString = GetConnectionString("TeamDBConnectionString");
            SqlConnection Con = new SqlConnection(sConString);
            SqlCommand Cmd = new SqlCommand();
            Cmd.Connection = Con;

            Con.Open();

Then set the CommandText property of SQLCommand and pass the parameters

String sSQLCmdText = "Select * from PlayerDetails where PlayerFirstName  = @FirstName";
            Cmd.CommandText = sSQLCmdText;
            Cmd.Parameters.AddWithValue("@FirstName", "Sachin");

Once this done, declare a SQLDataReader and get the rows into it

SqlDataReader rdr = Cmd.ExecuteReader();

            while (rdr.Read() == true)
            {
              string sPlayerName =  rdr.GetString(1);
            }
            
            Con.Close();

You can also pass the FieldName as parameter to query

SQLDataReader - Invalid attempt to read when no data is present

The error occurs when there no data is returned / the data has not been read.

The first case can be checked using HasRows flag

If the data is not read it can be done as follows:

SqlDataReader rdr = Cmd.ExecuteReader();

            while (rdr.Read() == true)
            {
              string sName =  rdr.GetString(1);
            }
      

SQLDataReader - Invalid attempt to read when no data is present

How to Add Generic List Items to ListBox in C# / VB.NET

We have already seen How to Add an ArrayList to ListBox. The following code shows how to add a C# Generic List to ListBox

        public void Load_LB_GenericList()
        {
            List Team = new List();
            ClassTeam CT = new ClassTeam(ClassTeam.playerType.Contract, "Sachin", 23, "33420242");
            Team.Add(CT);
            CT = new ClassTeam(ClassTeam.playerType.Contract, "Sourav", 23, "33420242");
            Team.Add(CT);
            CT = new ClassTeam(ClassTeam.playerType.Contract, "Dravid", 23, "33420242");

            Team.Add(CT);
            listBox1.DataSource = Team;
            listBox1.DisplayMember = "Name";
            listBox1.ValueMember = "Phone";

        }

How to assign an ArrayList to ListBox in .NET (C#)

How to add ArrayList items to ListBox (VB.NET/C#) / How to Add Objects to ListBox using C# (.NET)

Let us consider an userform with a listbox. We now need to assign the Arraylist to the Listbox.

We go back to our Teamexample. We have a class called ClassTeam with following properties

     class ClassTeam
    {
        #region declarations
        public enum playerType { ClassA, ClassB, ClassC, Contract }
        private playerType _PlayerType;
        string _Name;
        int _Age;
        string _Phone;


        #endregion

        #region properties
        public playerType PlayerType
        {
            //accessor
            get { return _PlayerType; }

            //mutator
            set
            {
                _PlayerType = value;
            }

        }

        public string Name
        {
            get { return _Name; }

            set
            {
                _Name = value;
            }
        }

        public string Phone
        {
            get { return _Phone; }

            set
            {
                _Phone = value;
            }
        }

        public int Age
        {
            get { return _Age; }

            set
            {
                _Age = value;
            }
        }
        #endregion

        #region public methods
        public string SetPlayer()
        {

            return null;
        }
        #endregion

        #region ClassTeam Construct
        public ClassTeam(playerType PT, string sName, int iAge, string sPhone )
        {
            PlayerType = PT;
            _Name= sName;
            _Age = iAge;
            _Phone = sPhone;
        }

    #endregion

    }

Now we create objects of the above class and add it to an Arraylist

            ArrayList Team = new ArrayList();
            ClassTeam CT = new ClassTeam(ClassTeam.playerType.Contract, "Sachin", 23, "33420242");
            Team.Add(CT);
            CT = new ClassTeam(ClassTeam.playerType.Contract, "Sourav", 23, "33420242");
            Team.Add(CT);
            CT = new ClassTeam(ClassTeam.playerType.Contract, "Dravid", 23, "33420242");

            Team.Add(CT);
 

The arraylist 'Team' will nowcontain three ClassTeam objects.

Assign the ArrayList as datasource to the listbox and set the displaymember and valuemember

            listBox1.DataSource = Team;
            listBox1.DisplayMember = "Name";
            listBox1.ValueMember = "Phone";

Some methods of ListBox will not be available when use DataSource.

Items collection cannot be modified when the DataSource property is set.

Sorted property of ListBox Throws error

{"Items collection cannot be modified when the DataSource property is set."}

The error occurs when you are trying to do something that is not allowed. For example, Sorting is not allowed in Listbox when it is linked to DataSource. If you need to sort, then sort the DataSet before linking it to Listbox

How to iterate MultiSelect ListBox using C# (.NET)

C# - Get Selected Values from MultiSelect ListBox

Here is a way of retrieving the selected values of Multiselect listbox

for (int i1 = 0; i1 < listBox1.SelectedItems.Count; i1++)
            {
                DataRowView D1 = listBox1.SelectedItems[i1] as DataRowView;

                MessageBox.Show(D1[1].ToString());
            }

The above code uses SelectedItems collection to retrieve information

How to Create MultiSelect Listbox in .NET (C#)

Enable MultiSelect in ListBox (C#/.NET)

Modifying the SelectionMode property of the listbox allows Multiple Items to be selected

MultiSelect Listbox in .NET (C#)

How to get the selected value of listbox using C# code

The following code retrieves the value of listbox and the accompanying text

private void listBox1_SelectedValueChanged(object sender, EventArgs e)
        {
            MessageBox.Show(listBox1.Text);
            MessageBox.Show(listBox1.SelectedValue.ToString());
        }

The above method retrieves the displaytext (DisplayMember) and the selected value (DisplayValue) from the selected item of listbox

How to Bind DataSet to ListBox using C#

How to add items from database to Listbox control using C#

The following code binds the PlayerDetails table with the listbox

string sConString = GetConnectionString("TeamDBConnectionString");
            SqlConnection Con = new SqlConnection(sConString);
            Con.Open();

            //Command Text
            String sSQLCmdText = "Select * from PlayerDetails";
            
            //Create a new SQL Data Adapter
            SqlDataAdapter DA = new SqlDataAdapter(sSQLCmdText , Con);
            
            DataSet DS = new DataSet("PlayerDS"); //DataSet

            DS.Clear();
            DA.Fill(DS, "Player");

            listBox1.DisplayMember = "PlayerName";
            listBox1.ValueMember = "PlayerID";
            listBox1.DataSource = DS.Tables["Player"];

            Con.Close();

How to retrieve specific connection string from App.Config file using C# (.NET)

Get specific connection string from App.Config file using C# (.NET)

The connection string can be retrieved from the App.Config file using ConnectionStrings method of ConfigurationManager. You need to add the following directive in the code:

using System.Configuration;

The ConnectionStrings method without any arguments will return a collection of Connection strings in the App.Config file. If you want to retrieve specific ones you can either pass an index or string to it

private static string retsettings(String sConnName)
        {
            try
            {
                ConnectionStringSettings sConnection = ConfigurationManager.ConnectionStrings[sConnName];
                return sConnection.ConnectionString;
            }
            catch (Exception ex1)
            {
                return null;
            }
            finally
            { }

            
        }

How to validate password using C# (.NET)

How to check password using C# Regular Expressions / How to enforce strong password using C# .NET

One of the common methods to check and validate password is through regular expressions. The criteria for strong password is :

1. Password should be minimum eight characters in length
2. Password should contain atleast a digit and an alphabet
3. Password should contain a non-alphanumeric character

The code uses Regular Expressions and hence the following directive is used:

using System.Text.RegularExpressions; 

The code below checks for the length:

if (sPassword.Length < 8 )
                {
                    throw new Exception("Password should contain mimimum 8 chars");   
                }

the code below checks for presence of atleast one number

sPattern = "\\d";
                oReg = new Regex(sPattern, RegexOptions.IgnoreCase);
                if (oReg.IsMatch(sPassword) == false)
                {
                    throw new Exception("Password should contain mimimum one numeric character");
                }

the code below checks for presence of atleast one alphabet

sPattern = "\\w";
                oReg = new Regex(sPattern, RegexOptions.IgnoreCase);
                if (oReg.IsMatch(sPassword) == false)
                {
                    throw new Exception("Password should contain mimimum one alphabet character");
                }

the code below checks for presence of atleast one non-alphanumeric character

string sPattern;
                sPattern = "[^a-zA-Z0-9\n\r\t ]";
                Regex oReg = new Regex(sPattern, RegexOptions.IgnoreCase);
                if (oReg.IsMatch(sPassword) == false)
                {
                    throw new Exception("Password should contain mimimum one non-alphanumeric character");   
                }

Exceptions are raised and handled if the criteria is not matching

How to Raise Exceptions in C# / .NET

Raise Error in C# (.NET) / Throw Error/Exception in C# (.NET)

The following code generates an exception if the supplied text (password) is less than eight characters.

try {
                if (sPassword.Length < 8 )
                {
                    throw new Exception("Password should contain mimimum 8 chars");   
                }
            }
                            catch(Exception ex1)
            {
                sMessage= ex1.Message.ToString();
                return false;
                            }
     

This way of raising user-defined exception helps in efficient way of handling exceptions

How to Add an Array to List using C# /.NET

Add Range to List using C# / .NET

Let us take our own IPL example. The current IPL has eight teams that are part of the list

            List lstIPLTeams = new List();

            lstIPLTeams.Add("Mumbai Indians");
            lstIPLTeams.Add("Chennai SuperKings");
            lstIPLTeams.Add("Kolkatta KnightRiders");
            lstIPLTeams.Add("Deccan Chargers");
            lstIPLTeams.Add("Rajastan Royals");
            lstIPLTeams.Add("Delhi DareDevils");
            lstIPLTeams.Add("KingsXI Punjab");
            lstIPLTeams.Add("RC Bangalore");

From next year two new teams- Pune and Kochi - will be part of IPL

Hence we are adding those two teams to an Array and adding the array using AddRange method

            string[] NewIPLTeams = { "Pune", "Kochi" };
            lstIPLTeams.AddRange(NewIPLTeams);

            Console.WriteLine("\nList After Add Range");
            Console.WriteLine("=======================");
            foreach (string IPL in lstIPLTeams)
            {
                Console.WriteLine(IPL.ToString());
            }

This will add Pune and Kochi to end of the list

How to Add and Sort Items in a list using C#

Adding and Sorting List Items using .NET (C#)

The following example creates a Generic list of IPL teams and sorts them


The following code does it:

List lstIPLTeams = new List();

            lstIPLTeams.Add("Mumbai Indians");
            lstIPLTeams.Add("Chennai SuperKings");
            lstIPLTeams.Add("Kolkatta KnightRiders");
            lstIPLTeams.Add("Deccan Chargers");
            lstIPLTeams.Add("Rajastan Royals");
            lstIPLTeams.Add("Delhi DareDevils");
            lstIPLTeams.Add("KingsXI Punjab");
            lstIPLTeams.Add("RC Bangalore");


            Console.WriteLine("List Before Sorting");
            Console.WriteLine("=======================");
            foreach (string IPL in lstIPLTeams)
            {
                Console.WriteLine(IPL.ToString());
            }

            //Sort the Items
            lstIPLTeams.Sort();

            Console.WriteLine("\nList After Sorting");
            Console.WriteLine("=======================");
            foreach (string IPL in lstIPLTeams)
            {
                Console.WriteLine(IPL.ToString());
            }

Here is the output

Private Constructors in C# / VB.NET

Use of Private Constructors in C# (.NET)

Here is an example of a Private Constructor

public class WicketCounter
    {
        //Private Constructor
        private WicketCounter() { }

        // No of Wickets
        public static int Wickets;
        // Public Method to Return the No of Wickets
        public static int WicketCount()
        {
            return ++Wickets;
        }

     
    }

The Class has a private constructor, a public static method and a static variable. The Method increments the Wicketcount (and hence the class itself is called wicketcounter) and the value is returned through Wickets var

WicketCounter.WicketCount();
            
            MessageBox.Show(WicketCounter.Wickets.ToString());

The declaration of private constructor prevents the creation of default constructor. Hence the class cannot be instantiated and doesn;t contain any instance fields or methods

How to Download File from Website using C# (.NET)

 How to Download File from Internet using C# (.NET)

private bool download_file_from_Net()

        {
            try
            {
                WebClient WC = new WebClient();
                String sWebLocation = "http://logic.stanford.edu/talks/Web2.0/microsoft-logo.jpg";
                String sLocalPath = "C:\\Temp\\New folder (2)\\microsoft-logo.jpg";
                WC.DownloadFile(sWebLocation, sLocalPath);
                return true;
            }

           catch (Exception ex1)
            {
                return false;
            }
        }
  

Following errors might occur if you do not use the Destination File Name

For example

                String sLocalPath = "C:\\Temp\\New folder (2)";

throws the following error
 InnerException = {"Access to the path 'C:\\Temp\\New folder (2)' is denied."}

and

                String sLocalPath = "C:\\Temp\\New folder (2)\\";

 throws the following one


System.Net.WebException was caught
  Message=An exception occurred during a WebClient request.
  InnerException: System.IO.DirectoryNotFoundException

       Message=Could not find a part of the path 'C:\Temp\New folder (2)\'.

How to Bind a Lisbox to Database in C# (.NET)

Bind Listbox to Dataset using Visual Studio

Following steps would help you in connected a database/dataset to the list box

Step1: Add a List Box control to the form and select the DataSource from quick edit

Step 2: Select appropriate data source type (We are going to connect to an SQL Server DB)


Step 3: Select Appropriate Database Model


Step 4: Add a connection to database and select appropriate DB

Step 5: Select appropriate field you want to show in listbox


A dataset will be created and will be used for it. You can write necessary code in listbox selectionchange events depending upon the business logic

Switching Application Types using Visual Studio

Converting Application Types using Visual Studio

Visual Studio helps you to change Console Application to Windows Forms Application as shown below. This will help if you want to have your output on Console; then you can change the type from WinForms to console and view the o/p.

Debug.Print and Debug.Assert in C#

VB Programmers would have used Debug.Print and Debug.Assert at will while debugging the code. These two statements come handy for efficient debugging of the code.

This can be done in C# using System.Diagnostics

using System.Diagnostics;

missing the above directive will cause 'The name 'Debug' does not exist in the current context" error

            int i1 = 0;
            while (i1 < 10)
            {
                Debug.Assert(i1 != 3);
                ++i1;
            }

System.IO.FileNotFoundException was unhandled

The error occurs when an attempt is made to open a file that is not available

The following statement

stream = File.Open("data.xml", FileMode.Open);

will throw an error if data.xml is not available

Program '..Sample.exe' has more than one entry point defined: '..Program.Main()'. Compile with /main to specify the type that contains the entry poin

Program '..Sample.exe' has more than one entry point defined: '..Program.Main()'. Compile with /main to specify the type that contains the entry point.

This error occurs when there are two Sub Main() functions in a solution

The type or namespace name 'SoapFormatter' could not be found (are you missing a using directive or an assembly reference?)

The type or namespace name 'Soap' does not exist in the namespace 'System.Runtime.Serialization.Formatters' (are you missing an assembly reference?)



The type or namespace name 'SoapFormatter' could not be found (are you missing a using directive or an assembly reference?)

Add the following reference to the project to solve the error

Accessors and mutators in C#

Accessors and mutators do the job of retrieving and storing the data to a class member. The class member will be usually private and hence cannot be accessed directly by the object.

The following code provides a hint of the same

       public enum playerType { ClassA, ClassB, ClassC, Contract }
       private playerType _PlayerType;
       string Name;
       string Age;
       string Phone;


       #endregion

       #region properties
       public playerType PlayerType
       {
           //accessor
           get { return _PlayerType; }

           //mutator
           set
           {
               _PlayerType = value;
           }

       }

Here _PlayerType is declared as private. This can be however accessed in the main program as shown below:

           ClassTeam CT = new ClassTeam();
           CT.PlayerType = ClassTeam.playerType.Contract; //Calls the Mutator
           MessageBox.Show(CT.PlayerType.ToString()); // Calls the Accessor

The statement CT.PlayerType = ClassTeam.playerType.Contract; Calls the Mutator (set property) and sets the value and CT.PlayerType.ToString() uses Get property and retrieves the value