Posts

Leetcode - 125. Valid Palindrome

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 Problem statement: A phrase is a   palindrome   if, after converting all uppercase letters into lowercase letters and removing all non-alphanumeric characters, it reads the same forward and backward. Alphanumeric characters include letters and numbers. Given a string  s , return  true   if it is a  palindrome , or  false  otherwise . Solution: Problem says, First convert all  uppercase letters into lowercase letters. Remove all non-alphanumeric characters. For first part, I will use ToLower() method of string class. this method will convert all the  uppercase letters into lowercase letters. For the second part, I will use Regex Replace method to remove all  non-alphanumeric characters.  public bool IsPalindrome(string s)   {         /*here i am checking if string is null or empty if so then it will be always                                           Palindrome so return true*/                if(string.IsNullOrEmpty(s))                return true;     /*in this statement i am first c

Pagination of DataGrid in WPF using MVVM

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In this Post i will explain the pagination using the MVVM pattern. Lets first create the View with DataGrid and pagination control with First, Previous, Next and Last buttons and we will also have the number of record per page to be displayed in DataGrid option which is ComboBox and in this DataGrid i will load data from CSV file. View I will create the view with DataGrid like this And in this DataGrid i will load data from CSV file <Window x:Class="CURD.Views.EmployeeDetails"         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"         xmlns:local="clr-namespace:CURD.Views"         mc:Ignorable="d"         Title="EmployeeDetails"         xmlns:sys="clr-namespace:Syste

Step by step guide to implement the command in wpf

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To create the custom command we need to implement ICommand interface which is having two method called CanExecute and Execute and one EventHandler called CanExecuteChanged. CanExecute method is responsible to tell if commend will execute or not. Execute method perform the action. Step to create custom command: Implement the ICommand write a constructor which will take two parameters of type Action and Func respectively. if you want to trigger CanExecute on property change then add the method which should invoke CanExecuteChanged  EventHandler . Why Action? Action delegate is used for performing the action. As our actual implementation of  this Action will present in our ViewModel and we need to pass ViewModel method as a constructor parameter so that we can assign it in our CustomCommand and can invoke when require. Why Func? Func delegate is used when we want to pass some value and return some value. As our actual implementation of  this Func will present in our ViewModel and we ne

How to implement custom paging on a WPF DataGrid?

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In this post we are going to learn the pagination in the data grid where we will have options to select the number of records to be displayed per page in the data grid. you can select the count from the record per page combobox and based on that you can see the records. I will add the four buttons which is used for show the first page, previous page, next page and last page. Below is DataGrid control code:  <DataGrid Grid.Row="1" ItemsSource="{Binding EmployeeCollection}"                    AutoGenerateColumns="False" CanUserAddRows="False">             <DataGrid.Columns>                 <DataGridTextColumn Header="ID" Binding="{Binding ID}"/>                 <DataGridTextColumn Header="Name" Binding="{Binding Name}"/>                 <DataGridTextColumn Header="Age" Binding="{Binding Age}"/>                 <DataGridTextColumn Header="Gender"

What is IoC Container?

  IoC Container IoC Container is a framework for implementing automatic dependency injection . before I explain IoC Container first lets know what is  dependency injection Dependency Injection It is a design pattern used to implement IoC. It allows the creation of dependent objects outside of a class and provides those objects to a class through different ways.  The Dependency Injection pattern involves three things which are client, service and the injector so, there will be  three  types of classes  involves in this process . Client Class : The client class is a class which depends on the service class. Service Class : The service class is a class that provides service to the client class. Injector Class : The injector class injects the service class object into the client class. The injector class injects dependencies in three ways: through a constructor, or through a property, or through a method. so, there are three types of Dependency Injection which are: Constructor Injection