Click here to Skip to main content
15,511,503 members
Please Sign up or sign in to vote.
0.00/5 (No votes)
See more:
hello sir,
i have 5 textbox ....
4 for entering input value and 5th one for storing result.
i used textchange event and those event i implemented in view(.cs file)..
but i want to implement same in view_model file...
how to to do the same using wpf and mvvm technique..

What I have tried:

<UserControl x:Class="task2.Views.calc"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:local="clr-namespace:task2.Views"
             mc:Ignorable="d" 
             d:DesignHeight="300" d:DesignWidth="300">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="auto"/>
            <RowDefinition Height="auto"/>
            <RowDefinition Height="auto"/>

        </Grid.RowDefinitions>
        <Grid>
            <Grid.RowDefinitions>
                <RowDefinition Height="auto"></RowDefinition>
                <RowDefinition Height="auto"></RowDefinition>
                <RowDefinition Height="auto"></RowDefinition>
                <RowDefinition Height="auto"></RowDefinition>
                <RowDefinition Height="auto"></RowDefinition>
                <RowDefinition Height="auto"></RowDefinition>
                <RowDefinition Height="auto"></RowDefinition>
                <RowDefinition Height="auto"></RowDefinition>
            </Grid.RowDefinitions>
            <Grid.ColumnDefinitions>
                <ColumnDefinition  Width="100"></ColumnDefinition>
                <ColumnDefinition  Width="150"></ColumnDefinition>
                <ColumnDefinition  Width="100"></ColumnDefinition>
                <ColumnDefinition  Width="150"></ColumnDefinition>

            </Grid.ColumnDefinitions>
            <Label x:Name="lblItem" Content="Materials" Grid.Row="0" Grid.Column="0" VerticalAlignment="Top"></Label>
            <Label x:Name="lblPrice" Content="Price" Grid.Row="0" Grid.Column="1" VerticalAlignment="Top"></Label>


            <Label x:Name="lblOil" Content="Oil" Grid.Row="1" Grid.Column="0" VerticalAlignment="Top"></Label>
            <TextBox x:Name="txtOil" Grid.Row="1" Grid.Column="1" VerticalAlignment="Top" TextChanged="txt1_TextChanged"  >
            </TextBox>

            <Label x:Name="lblRice" Content="Rice" Grid.Row="2" Grid.Column="0" VerticalAlignment="Top"></Label>
            <TextBox x:Name="txtRice" Grid.Row="2" Grid.Column="1" VerticalAlignment="Top" TextChanged="txt2_TextChanged">
            </TextBox>

            <Label x:Name="lblCoconut" Content="Cocunut" Grid.Row="3" Grid.Column="0" VerticalAlignment="Top"></Label>
            <TextBox x:Name="txtCoconut" Grid.Row="3" Grid.Column="1" VerticalAlignment="Top" TextChanged="txt3_TextChanged" >
            </TextBox>

            <Label x:Name="lblDal" Content="Dal" Grid.Row="4" Grid.Column="0" VerticalAlignment="Top"></Label>
            <TextBox x:Name="txtDal" Grid.Row="4" Grid.Column="1" VerticalAlignment="Top" TextChanged="txt4_TextChanged">
            </TextBox>

            <Label x:Name="lblTotal" Content="Total" Grid.Row="5" Grid.Column="0" VerticalAlignment="Top"></Label>
            <TextBox x:Name="txtTotal" Grid.Row="5" Grid.Column="1" VerticalAlignment="Top" >
            </TextBox>

            <Label x:Name="lbltax" Content="Tax" Grid.Row="6" Grid.Column="0" VerticalAlignment="Top"></Label>
            <TextBox x:Name="txttax" Grid.Row="6" Grid.Column="1" VerticalAlignment="Top" >
            </TextBox>

            <Label x:Name="lblvat" Content="gst" Grid.Row="7" Grid.Column="0" VerticalAlignment="Top"></Label>
            <TextBox x:Name="txtvat" Grid.Row="7" Grid.Column="1" VerticalAlignment="Top" >
            </TextBox>
        </Grid>
        <!--<Button x:Name="btnUpdate" Width="100" Height="20" HorizontalAlignment="Center" Grid.Row="1" Content="Update"
                Command="{Binding Path=UpdateCommand}" ></Button>
        <ListView x:Name="lstPerson" Grid.Row="2" ItemsSource="{Binding Persons}">
            <ListView.View>
                <GridView>
                    <GridViewColumn Header="Materials" DisplayMemberBinding="{Binding Name}" />
                    <GridViewColumn Header="Price" Width="200" DisplayMemberBinding="{Binding Address}"/>
                </GridView>
            </ListView.View>
        </ListView>-->

    </Grid>
</UserControl>

C#
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace task2.Views
{
    /// <summary>
    /// Interaction logic for calc.xaml
    /// 
    public partial class calc : UserControl
    {
        public calc()
        {
            InitializeComponent();
        }

        protected void txt1_TextChanged(object sender, EventArgs e)
        {
            if ((!string.IsNullOrEmpty(txtOil.Text)) && (!string.IsNullOrEmpty(txtRice.Text)) && (!string.IsNullOrEmpty(txtCoconut.Text)) && (!string.IsNullOrEmpty(txtDal.Text)))
            {
                txtTotal.Text = (Convert.ToInt32(txtOil.Text) + Convert.ToInt32(txtRice.Text) + Convert.ToInt32(txtCoconut.Text) + Convert.ToInt32(txtDal.Text)).ToString();
            }
            CalculateTax();
        }
        protected void txt2_TextChanged(object sender, EventArgs e)
        {
            if ((!string.IsNullOrEmpty(txtOil.Text)) && (!string.IsNullOrEmpty(txtRice.Text)&& (!string.IsNullOrEmpty(txtCoconut.Text))&& (!string.IsNullOrEmpty(txtDal.Text))))
            {
                txtTotal.Text = (Convert.ToInt32(txtOil.Text) + Convert.ToInt32(txtRice.Text) + Convert.ToInt32(txtCoconut.Text) + Convert.ToInt32(txtDal.Text)).ToString();
            }
            CalculateTax();
        }
        protected void txt3_TextChanged(object sender, EventArgs e)
        {
            if ((!string.IsNullOrEmpty(txtOil.Text)) && (!string.IsNullOrEmpty(txtRice.Text)) && (!string.IsNullOrEmpty(txtCoconut.Text)) && (!string.IsNullOrEmpty(txtDal.Text)))
            {
                txtTotal.Text = (Convert.ToInt32(txtOil.Text) + Convert.ToInt32(txtRice.Text) + Convert.ToInt32(txtCoconut.Text) + Convert.ToInt32(txtDal.Text)).ToString();
            }
            CalculateTax();
        }
        protected void txt4_TextChanged(object sender, EventArgs e)
        {
            if ((!string.IsNullOrEmpty(txtOil.Text)) && (!string.IsNullOrEmpty(txtRice.Text)) && (!string.IsNullOrEmpty(txtCoconut.Text)) && (!string.IsNullOrEmpty(txtDal.Text)))
            {
                txtTotal.Text = (Convert.ToInt32(txtOil.Text) + Convert.ToInt32(txtRice.Text) + Convert.ToInt32(txtCoconut.Text) + Convert.ToInt32(txtDal.Text)).ToString();
            }
            CalculateTax();
        }

        public void CalculateTax()
        {
            if ((!string.IsNullOrEmpty(txtTotal.Text)))
                {
                int Amount = Convert.ToInt32(txtTotal.Text);
                txtvat.Text = (((Amount * 12) / 100) + Amount).ToString();

                if (Amount > 2000)
                {
                    txttax.Text = "20";
                }
                else if (Amount > 1000)
                {
                    txttax.Text = "10";
                }
                else
                {
                    txttax.Text = "5";
                }
            }
        }

        public bool IsValid()
        {
            int Amount = Convert.ToInt32(txtTotal.Text);
            if (Amount == 0)
            {
                return false;
            }
            else
            {
                return true;
            }
        }
    }
}
Posted
Updated 4-Oct-21 3:09am
v3

1 solution

Here is an example of how...
XML
<Window x:Class="WpfCalc.MainWindow"
        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:WpfCalc"
        mc:Ignorable="d"
        Title="MainWindow" Height="350" Width="525">

    <Window.DataContext>
        <local:CalcViewModel/>
    </Window.DataContext>
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="auto"/>
            <RowDefinition Height="auto"/>
            <RowDefinition Height="auto"/>
            <RowDefinition Height="auto"/>
            <RowDefinition Height="auto"/>
            <RowDefinition Height="auto"/>
            <RowDefinition Height="auto"/>
            <RowDefinition Height="auto"/>
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition  Width="100"/>
            <ColumnDefinition  Width="150"/>
            <ColumnDefinition  Width="100"/>
            <ColumnDefinition  Width="150"/>

        </Grid.ColumnDefinitions>
        <Label x:Name="lblItem" Content="Materials" Grid.Row="0" Grid.Column="0" VerticalAlignment="Top"></Label>
        <Label x:Name="lblPrice" Content="Price" Grid.Row="0" Grid.Column="1" VerticalAlignment="Top"></Label>


        <Label x:Name="lblOil" Content="Oil" Grid.Row="1" Grid.Column="0" VerticalAlignment="Top"></Label>
        <TextBox x:Name="txtOil" Grid.Row="1" Grid.Column="1" VerticalAlignment="Top"
                    Text="{Binding Oil, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />

        <Label x:Name="lblRice" Content="Rice" Grid.Row="2" Grid.Column="0" VerticalAlignment="Top"></Label>
        <TextBox x:Name="txtRice" Grid.Row="2" Grid.Column="1" VerticalAlignment="Top"
                    Text="{Binding Rice, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />

        <Label x:Name="lblCoconut" Content="Cocunut" Grid.Row="3" Grid.Column="0" VerticalAlignment="Top"></Label>
        <TextBox x:Name="txtCoconut" Grid.Row="3" Grid.Column="1" VerticalAlignment="Top" 
                    Text="{Binding Coconut, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />

    </Grid>

</Window>

and the ViewModel:
C#
using System.ComponentModel;

namespace WpfCalc
{
    public class CalcViewModel : INotifyPropertyChanged
    {
        public CalcViewModel()
        {
            Oil = 123.456F;
            Rice = 222.222F;
            Coconut = 333.333F;
        }

        private float oil;
        public float Oil
        {
            get { return oil; }
            set
            {
                if (oil != value)
                {
                    oil = value;
                    NotifyPropertyChanged(nameof(Oil));

                }
            }
        }

        private float rice;
        public float Rice
        {
            get { return rice; }
            set
            {
                if (rice != value)
                {
                    rice = value;
                    NotifyPropertyChanged(nameof(Rice));

                }
            }
        }

        private float coconut;
        public float Coconut
        {
            get { return coconut; }
            set
            {
                if (coconut != value)
                {
                    coconut = value;
                    NotifyPropertyChanged(nameof(Coconut));

                }
            }
        }

        #region INotifyPropertyChanged

        public event PropertyChangedEventHandler PropertyChanged;

        public void NotifyPropertyChanged(string propertyName)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }

        #endregion
    }
}


Also, check out MVVM Light Toolkit - Nuget[^]
 
Share this answer
 

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)



CodeProject, 20 Bay Street, 11th Floor Toronto, Ontario, Canada M5J 2N8 +1 (416) 849-8900