Showing posts with label c sharp. Show all posts
Showing posts with label c sharp. Show all posts

Saturday 11 September 2021

simple use of Record in c#9 and newer versions

 c# 9 introduces a new keyword Record which makes an object immutable. Properties in the record can be initialised at the time of creation or constructor call only. Record can be written like how we write a class. It has same syntax as class.

For example:

public record Friend


            public Friend()



            public Friend(string name, string surname)


                this.Name = name;

                this.Surname = surname;


            public string Name { get; init; }

            public string Surname { get; init; }


use of Friend record:

var newFriend = new Friend("Tom", "Pandey");

//--Note: we called here using constructor.

var newFriend1 = new Friend{Name="Tom",Surname= "Pandey"};

//Note: this calls the constructor without parameter. constructor without parameter is not required to to call to initiate the record. 

This record is equivalent to below code which don't have a constructor:

public record Friend


            public string Name { get; init; }

            public string Surname { get; init; }


use of Friend Record:

var newFriend = new Friend("Tom", "Pandey");

Note: we called here using constructor, but we don't have constructor defined. so It will throw an error. Instead we create object friend like this:

var newFriend1 = new Friend{Name="Tom",Surname= "Pandey"};

In both the example of Record, we can not modify the property Name or Surname after the object is created. 

The Friend record with constructor can be written as below code in one line:

public record Friend(String Name, String Surname);

use of Friend Record: 

Friend friend = new Friend("John","Pandey" );

Note: since this is constructor type record, we must create record object using constructor.for example below code will throw error:

var newFriend1 = new Friend{Name="Tom",Surname= "Pandey"};

On compilation, this is converted to class with immutable properties.

Monday 7 September 2020

Unit test c#: Create Fake Httpcontext to bypass Null exception for User object

 Microsoft Visual studio Test Framework

Requirement: Nuget package Moq (or later)

Settings in visual studio: Menu->Tools->Options ->Debugging->General
Tick "Use Managed Compatibility Mode"

Code: (copied from stackoverflow)
Step 1: 
Create a new class FakeHttpContext and paste the below code. Change the Returns value to whatever user name you need.

public static class FakeHttpContext
        public static void SetFakeContext(this Controller controller)

            var httpContext = MakeFakeContext();
            ControllerContext context =
            new ControllerContext(
            new RequestContext(httpContext,
            new RouteData()), controller);
            controller.ControllerContext = context;

        private static HttpContextBase MakeFakeContext()
            var context = new Mock<HttpContextBase>();
            var request = new Mock<HttpRequestBase>();
            var response = new Mock<HttpResponseBase>();
            var session = new Mock<HttpSessionStateBase>();
            var server = new Mock<HttpServerUtilityBase>();
            var user = new Mock<IPrincipal>();
            var identity = new Mock<IIdentity>();

            context.Setup(c => c.Request).Returns(request.Object);
            context.Setup(c => c.Response).Returns(response.Object);
            context.Setup(c => c.Session).Returns(session.Object);
            context.Setup(c => c.Server).Returns(server.Object);
            context.Setup(c => c.User).Returns(user.Object);
            user.Setup(c => c.Identity).Returns(identity.Object);
            identity.Setup(i => i.IsAuthenticated).Returns(true);
            identity.Setup(i => i.Name).Returns("sanjeeb");

            return context.Object;

Step 2: 
Initialize the Fakehttpcontext in test initialize function. 


Wednesday 5 August 2020

Read TFS Project name from TFS Project collection using c#

Using Team foundation api.
C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE\ReferenceAssemblies\v2.0\Microsoft.TeamFoundation.dll
C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE\ReferenceAssemblies\v2.0\Microsoft.TeamFoundation.Client.dll
C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE\ReferenceAssemblies\v2.0\Microsoft.TeamFoundation.Common.dll
C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE\ReferenceAssemblies\v2.0\Microsoft.TeamFoundation.WorkItemTracking.Client.dll

using Microsoft.TeamFoundation.Client;
using Microsoft.TeamFoundation.Server;
using System;
using System.Linq;

class Program
{ private static ICommonStructureService _commonStructureService;
static void Main(string[] args)
 public static void ReadProject(String URL)
writeFile("Project Collection: " + URL);
TfsTeamProjectCollection tpc = new TfsTeamProjectCollection(new Uri(URL));
var collection = TfsTeamProjectCollectionFactory.GetTeamProjectCollection(tpc.Uri);
_commonStructureService = collection.GetService<ICommonStructureService>(); var projects = _commonStructureService.ListAllProjects().OrderBy(a => a.Name);
foreach (var project in projects)

} public static void writeFile(String message) {
using (System.IO.StreamWriter file =
new System.IO.StreamWriter(@"C:\temp\tfs.txt"true))

Output is the list of project names in tfs.txt file. 

Entity Framework Core with Existing Database

Entity Framework Core only supports code first database aproach. 
To use existing database, we'll need to reverse Engineer Model from existing Database. 
  • Open Visual studio.
  • Menu > tools >Nuget Package Manager >
  • open PM Console
Note: All the tables in the database must have Primary key defined. else you'll get error like:
Unable to generate entity type for table 'dbo.xOrdersMBS'.
Unable to identify the primary key for table 'dbo.xActivePricesEPB'.
Unable to generate entity type for table 'dbo.xActivePricesEPB'.
Unable to identify the primary key for table 'dbo.xLeadTimePBOM'.
Unable to generate entity type for table 'dbo.xLeadTimePBOM'.

 In the console, run the below power shell commands:

Using Windows Authentication:
Scaffold-DbContext "Server=DatabaseServerAddress;Database=DatabaseName;Trusted_Connection=True;" Microsoft.EntityFrameworkCore.SqlServer -OutputDir Models -f

Using SQL Account:
Scaffold-DbContext "data source=DatabaseServerAddress;initial catalog=DatabaseName;uid=UserName;pwd=Password;" Microsoft.EntityFrameworkCore.SqlServer -OutputDir Models -f

Note: -f force create the files if the file exist in the folder Models.

Thursday 2 July 2020

EntityFramework Insert error due to PrimaryKey

MyProject.Controllers.CurrencyCodesController Unable to update the EntitySet 'CurrencyCodes' because it has a DefiningQuery and no <InsertFunction> element exists in the <ModificationFunctionMapping> element to support the current operation.
System.Data.Entity.Infrastructure.DbUpdateException: Unable to update the EntitySet 'CurrencyCodes' because it has a DefiningQuery and no <InsertFunction> element exists in the <ModificationFunctionMapping> element to support the current operation. ---> System.Data.Entity.Core.UpdateException: Unable to update the EntitySet 'CurrencyCodes' because it has a DefiningQuery and no <InsertFunction> element exists in the <ModificationFunctionMapping> element to support the current operation.

The error occured while trying to insert the currencycodes entity to the database. 
public ActionResult Create([Bind(Include = "cucCurrencyCode,cucDescription,cucMultiplier,cucRate,cucInUse")] CurrencyCode currencyCode)
{ if (ModelState.IsValid)
{ try
{ db.CurrencyCodes.Add(currencyCode);
 catch (Exception ex) {
log.Error(ex.Message, ex);
 return RedirectToAction("Index");
} return View(currencyCode);


1) Check Primary key in .edmx file.  In my case cucInUse was set as Entity key. I removed it.
2) Now Right click the .edmx file and click "Open with...". Select XML (text) Editor
3)  Find the element <EntitySet name = "CurrencyCodes"...>
4) Change store:Schema="dbo" => Schema="dbo"
5) delete element <DefiningQuery>
6) Clean the project. 
7) close Visual studio.
8) Open visual studio. Open the project. 
9) Clean and build the project. 
10) Run the application.

Friday 26 June 2020

Use log4net for all logging in c# application

Exception logging is hugely important within an application, not just to ensure we know when an error has occured but also to help use trace back the thread to help investigate where the error originated.
Our strategy is to use log4net for all our logging needs.
This page helps cover the follow areas
1. Setting up logging across the entire applications
2. Including 2 appenders so we can be notified when they occur and ensure a tracable debug log file is available.
Setting up your Applications for Logging
Reference log4net in your applications
in Global.asax under the start_application method include the following
    void Application_Start(object sender, EventArgs e)
        // link up log4net configuration
On the page where you wish to log information declare a new static variable in the class header
log4net.ILog log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
Whenever you wish to now log an event in this class run one of the follow commands, ensure you include the exception when needed
log.Error("An unhandled exception occured", ex);
To ensure you catch all unhandled exceptions include the following in your Global.asax file. Remember to declare the log variable in the class too.
    void Application_Error(object sender, EventArgs e) 
        // Code that runs when an unhandled error occurs
        // get last exception
        Exception ex = Server.GetLastError().GetBaseException();
        // log it
        log.Error("An unhandled exception occured", ex);
Web.Config Settings
    <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net"/>
    <!-- The DebugFileAppender writes all messages to a log file-->
    <appender name="DebugFileAppender" type="log4net.Appender.RollingFileAppender">
      <file value="L:\[APPNAME]\Log.txt" /> <!-- These should be located on the "L" drive (if available) and stored under a folder named for the specific application -->      <datePattern value="'ApplicationLog.'yyyy-MM-dd'.txt'" />
      <staticLogFileName value="false" />
      <rollingStyle value="Composite" />
      <maxSizeRollBackups value="10" />
      <maximumFileSize value="5MB" />
      <appendToFile value="true" />
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%d [%t] %-5p %c %m%n" />
    </appender>    <!-- The EmailAppender sends an email when something matches the filters-->
    <appender name="EmailAppender" type="log4net.Appender.SmtpAppender">
      <evaluator type="log4net.Core.LevelEvaluator">
        <threshold value="DEBUG"/>
      <!--  The filters are processed in order:
            1) match the Inserted New User message
            2) match any WARN or higher messages
            3) reject everything else -->
      <filter type="log4net.Filter.StringMatchFilter">
        <stringToMatch value="Inserted a new user" />
        <acceptOnMatch value="true" />
      <filter type="log4net.Filter.LevelRangeFilter">
        <levelMin value="WARN" />
        <acceptOnMatch value="true" />
      <filter type="log4net.Filter.DenyAllFilter" />
      <!--  The SmtpAppender authenticates against the mail server, the buffersize of 10 provides 10 lines
            of context when an error happens. -->
      <subject value="[SEVERITY] [ENV] [APPNAME] - [EXCP_MSG]" />
      <to value="" />
      <from value="" />
      <smtpHost value="" />
      <bufferSize value="10" />
      <lossy value="true" />
      <layout type="log4net.Layout.PatternLayout">
        <param name="ConversionPattern" value="%d [%t] %-5p %c %m%n" />
    <appender name="EventLogAppender" type="log4net.Appender.EventLogAppender" >
      <applicationName value="MyApp" />

     <layout type="log4net.Layout.PatternLayout">

        <conversionPattern value="%date [%thread] %-5level %logger [%property{NDC}] - %message%newline" />



      <!-- add other appenders here and the log messages will be sent to every listed appender -->
      <appender-ref ref="DebugFileAppender" />
      <appender-ref ref="EmailAppender" />

Create XML from class or Object in C-Sharp

function to serialize object to xml in c#

public static string SerializeObjectToXML(object item)
                string xmlText;
                Type objectType = item.GetType();
                XmlSerializer xmlSerializer = new XmlSerializer(objectType);
                MemoryStream memoryStream = new MemoryStream();
                using (XmlTextWriter xmlTextWriter =
                    new XmlTextWriter(memoryStream, Encoding.UTF8) { Formatting = Formatting.Indented })
                    xmlSerializer.Serialize(xmlTextWriter, item);
                    memoryStream = (MemoryStream)xmlTextWriter.BaseStream;
                    xmlText = new UTF8Encoding().GetString(memoryStream.ToArray());
                    return xmlText;
            catch (Exception e)
                return null;

How to delete Local_lvm storage and resize local storage to use full disk space?

1) Delete the Local_lvm from othe proxmox interface . "datacenter" > Storage. Select the local_lvm storage and click "Remo...