On Button Click validation in WPF

Question

I am working on the WPF application. In my application there are different forms which save the data. I want to validation the data on button click or while lost focus from control. I want WPF validations work likes ASP.Net validation.

I do not know the form validate after page load. It should only validate when user lost focus from control or while user click on button.

I have done lot of R&D on google. But I did found any proper setup by setup solution.

Please help me out.

Answer 1

In this example I show you two text box with validation...

XAML Coding......

    <TextBlock Text="Throw Exception in Property" Grid.Column="1" Grid.Row="0" VerticalAlignment="Center" FontSize="22" Foreground="Chocolate" />
    <TextBlock Text="Name " Grid.Column="0" Grid.Row="1" VerticalAlignment="Center" HorizontalAlignment="Center" FontSize="15" Foreground="DarkGreen" />
    <TextBlock Text="Age" Grid.Column="0" Grid.Row="2" VerticalAlignment="Center" HorizontalAlignment="Center" FontSize="15" Foreground="DarkGreen" />

    <TextBox Name="txtName" Grid.Row="1" Grid.Column="2" HorizontalAlignment="Left" Width="170" Height="30" Background="Azure" Text="{Binding Path=pName,Mode=TwoWay,ValidatesOnExceptions=True}"/>
    <TextBox Name="txtAge" Grid.Row="2" Grid.Column="2" HorizontalAlignment="Left" Width="170" Height="30" Background="Azure" Text="{Binding Path=pAge,Mode=TwoWay,ValidatesOnExceptions=True}"/>
    <Button Name="btnSubmit" Content="Submit" Grid.Row="4" Height="30" Click="btnSubmit_Click"/>

C# Coding

    private void Page_Loaded(object sender, RoutedEventArgs e)
    {
        Student s = new Student();
        this.DataContext = s;
    }

    public class Student : INotifyPropertyChanged
    {
        string name;
        int age;

        public string pName
        {
            get 
            {
                return name;
            }

            set
            {
                if (string.IsNullOrWhiteSpace(value))
                {
                    throw new ArgumentException("Name field must be enterd.");
                }
                name = value;
                OnPropertyChanged("pName");
            }
        }

        public int pAge
        {
            get
            {
                return age;
            }
            set
            {
                if(!Regex.IsMatch(value.ToString(),"[0-9]"))
                {
                    throw new ArgumentException("Age field must be in number.");
                }

                if(value < 18 || value > 100)
                {
                    throw new ArgumentException("Age field must be 18-100.");
                }

                age = value;
                OnPropertyChanged("pAge");
            }
        }


        public event PropertyChangedEventHandler PropertyChanged;

        public void OnPropertyChanged(string data)
        {
            if (PropertyChanged != null)
            { 
                PropertyChanged(this,new PropertyChangedEventArgs(data));
            }
        }

    }