绑定C＃和XAML错误

Question

I have the following code which I should put a random number in the content of a button.But rather everytime the content of the button is the same value 0 - This is part of my C# code-

public sealed partial class MainPage : Page
    {
        public MainPage()
        {
            this.InitializeComponent();
            this.DataContext = this;
            this.NavigationCacheMode = NavigationCacheMode.Required;
        }
        public int RandomNumber { get; set; }
        public int GenerateRandomNumber(int min, int max)
        {
            Random random = new Random();
            return random.Next(5,40);
        }

  private void ButtonNo3(object sender, RoutedEventArgs e)
    {
        int ans = 0;
        Button obj = (Button)sender;
        var selectedButton = obj.Content.ToString(); 
        //some more code
    }

This is part of my XAML code in which my button should have a random number in its content-

            <Button 
            x:Name="Button3"
            Content="{Binding Path=RandomNumber}"                           
            Click="ButtonNo3"
            HorizontalAlignment="Left" 
            Margin="0,118,0,0" 
            VerticalAlignment="Top" 
            Height="37" 
            Width="47"/>

SO my question is why is the Content of the Button3 always 0 when it should be random.

Answer 1

您不会在任何地方（至少不在显示的代码中）调用GenerateRandomNumber函数，因此RandomNumber属性将始终具有默认值0。

Answer 2

Following should do the trick

public sealed partial class MainPage : Page,INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;
    private int __RandomNumber;

    public MainPage()
    {
        this.InitializeComponent();
        this.DataContext = this;
        this.NavigationCacheMode = NavigationCacheMode.Required;
    }
    public int RandomNumber 
    { 
        get{return _RandomNumber} 
        set
        {
            if (_RandomNumber != value){
              _RandomNumber = value;
              this.OnPropertyChanged("RandomNumber");//needed for binding
            }
        }; 
    }
    public int GenerateRandomNumber(int min, int max)
    {
        Random random = new Random();
        RandomNumber = random.Next(5,40); //changed this line, do the assign
        return RandomNumber;
    }

    private void ButtonNo3(object sender, RoutedEventArgs e)
    {
        int ans = 0;
        Button obj = (Button)sender;
        var selectedButton = obj.Content.ToString(); 
        //some more code
        GenerateRandomNumber(0,0);  //added : generate a random number
    }

There are multiple issues that i solved with this code. You are never generating a random number, not assigning it either. You are not implementing inotifypropertychanged so even if you were the generate a new number it would not be picked up by the binding. The code above is not tested, it may have still some issues, but it should give you an idea.

Answer 3

As already stated you're not calling the GenerateRandomNumber method any where. You need to set the content property of the button to the value returned by the random number method.

To get a different value every time put this code before you set your selectedButton variable in the click event.

obj.Content = GenerateRandomNumber(5,40);
var selectedButton = obj.Content;

On another note. The parameters for your GenerateRandomNumber method are useless. You're not using them.you should be doing this:

private int GenerateRandonNumber( int min, int max ) {
    Random random = new Random();
    return random.Next( min, max );
}