How to send Some Value in Button to Textbox in c sharp? [closed]

Hi just add simple code to your buttons, Concern about validations and things.

    private void plusButton_Click(object sender, EventArgs e)
    {
        if (string.IsNullOrEmpty(textBox2.Text))
        {
            int count = 0;
            textBox2.Text = count.ToString();
        }
        else
        {
            int count = Convert.ToInt16(textBox2.Text);
            ++count;
            textBox2.Text = count.ToString();
        }
    }

    private void minusButton_Click(object sender, EventArgs e)
    {
        if (textBox2.Text == "0" || string.IsNullOrEmpty(textBox2.Text))
        {
            //do nothing
        }
        else
        {
            int count = Convert.ToInt16(textBox2.Text);
            --count;
            textBox2.Text = count.ToString();
        }
    }

The simplest version I can imagine would be this one:

.xaml

<StackPanel>
    <TextBox x:Name="SomeTextBox" Text="Old Text"/>
    <Button Content="Sender" Click="Button_Click" />
</StackPanel>

.xaml.cs

private void Button_Click(object sender, RoutedEventArgs e)
{
    SomeTextBox.Text = "NewText";
}

Seeing that you are building a shop you may want to dive a bit deeper into WPF.

Consider making you Product a Model in the MVVM sense of the word and create a View to display it and connect them using a viewmodel.

Make a CartItem as a Model,… make a cart as a model,…

Here is a more complex example that points you into that direction.
.xaml

<StackPanel>
    <Button Content="+" Command="{Binding ProductInc}" CommandParameter="{Binding Cola}"  />
    <TextBlock Text="{Binding Cola.Count, Mode=OneWay}"/>
    <Button Content="-" Command="{Binding ProductDec}" CommandParameter="{Binding Cola}"  />
</StackPanel>

.xaml.cs

public class Product : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;
    private int count = 0;
    public int Count
    {
        get { return count; }
        set
        {
            if (value == count) return;
            count = value;
            if (null == PropertyChanged) return;
            PropertyChanged(this, new PropertyChangedEventArgs("Count"));
        }
    }
}

class SimpleCommand<T> : ICommand
{
    public event EventHandler CanExecuteChanged;
    public bool CanExecute(object parameter) { return true; }
    private Action<T> execute;
    public SimpleCommand(Action<T> execute) { this.execute = execute; }
    public void Execute(object parameter) { execute((T)parameter); }
}


public partial class MainWindow : Window
{
    public Product Cola { get; set; }
    public ICommand ProductInc { get { return new SimpleCommand<Product>(OnProductInc); } }
    public ICommand ProductDec { get { return new SimpleCommand<Product>(OnProductDec); } }
    private void OnProductInc(Product product) { ++product.Count; }
    private void OnProductDec(Product product) { --product.Count; }
    public MainWindow()
    {
        Cola = new Product { Count = 0 };
        this.DataContext = this;
        InitializeComponent();
    }
}