WPF：将变量从父 xaml 传递给用户控件

WPF: Passing variables from parent xaml to usercontrol

提问by Franky

I'm trying to pass int variable from MainWindow.xaml to UserControl. When I'm debbuging myGridSize is always equal zero. I would appreciate any help.

我试图将 int 变量从 MainWindow.xaml 传递给 UserControl。当我调试时 myGridSize 总是等于零。我将不胜感激任何帮助。

MainWindow.xaml

主窗口.xaml

x:Name="myWindow">
 <Grid>
        <my:SudokuGrid x:Name="mySudokuGrid" myGridSize="{Binding SudokuSize, ElementName=myWindow}">
        </my:SudokuGrid>
</Grid>

MainWindow code

主窗口代码

    public static readonly DependencyProperty SudokuSizeProperty =
        DependencyProperty.Register("SudokuSize", typeof(int), typeof(MainWindow), new FrameworkPropertyMetadata(null));
    private int SudokuSize
    {
        get { return (int)GetValue(SudokuSizeProperty); }
        set { SetValue(SudokuSizeProperty, value); }
    }

    public MainWindow()
    {
        SudokuSize = 9;
        InitializeComponent();
    }

UserControl.xaml

用户控件.xaml

x:Name="gridCustom">
    <UniformGrid Name="SudokuUniGrid" Style="{StaticResource CustomGridStyle}">
    </UniformGrid>

UserControl code

用户控制代码

    public static readonly DependencyProperty myGridSizeProperty =
        DependencyProperty.Register("myGridSize", typeof(int), typeof(SudokuGrid), new FrameworkPropertyMetadata(null));

    public int myGridSize
    {
        get { return (int)GetValue(myGridSizeProperty); }
        set { SetValue(myGridSizeProperty, value); }
    }


    UniformGrid BuildGrid()
    {
        //myGridSize = 9;           
        UniformGrid theGrid = new UniformGrid();
        for (int i = 0; i < myGridSize * myGridSize; ++i)
        {
            myButton button = new myButton();
            button.cmLen = myGridSize;
            button.Width = 30;
            button.Height = 30;
            button.Tag = i;
            theGrid.Children.Add(button);            
        }
        return theGrid;
    }

    public SudokuGrid()
    {
        InitializeComponent();
        SudokuUniGrid.Children.Add(BuildGrid());
    }

回答by d.moncada

A few issues.

几个问题。

Your dependency propertyneeds to be registered to the user controltype. Also you need to wait for the user controlto be fully loaded before accessing.

您dependency property需要注册到该user control类型。您还需要等待user control完全加载才能访问。

MainWindow.xaml

主窗口.xaml

<Window x:Class="WpfApplication5.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:WpfApplication5"
        mc:Ignorable="d"
        Title="MainWindow" Height="350" Width="525"
        x:Name="myWindow">
    <Grid>
        <local:SudokuUniGrid myGridSize="{Binding SudokuSize, ElementName=myWindow}">
        </local:SudokuUniGrid>
    </Grid>
</Window>

MainWindow.xaml.cs

主窗口.xaml.cs

public partial class MainWindow : Window
{
    public static readonly DependencyProperty SudokuSizeProperty =
        DependencyProperty.Register("SudokuSize", typeof(int), typeof(MainWindow), new FrameworkPropertyMetadata(null));

    private int SudokuSize
    {
        get { return (int)GetValue(SudokuSizeProperty); }
        set { SetValue(SudokuSizeProperty, value); }
    }

    public MainWindow()
    {
        SudokuSize = 9;
        InitializeComponent();
    }
}

SudokiGrid.xaml(user control)

SudokiGrid.xaml（用户控件）

<UserControl x:Class="WpfApplication5.UserControl"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <UniformGrid x:Name="SudokuUniGrid">
    </UniformGrid>
</UserControl>

SudokiGrid.xaml.cs(user control)

SudokiGrid.xaml.cs（用户控件）

public class SudokuUniGrid : UserControl
{
    public static readonly DependencyProperty myGridSizeProperty =
        DependencyProperty.Register("myGridSize", typeof(int), typeof(UserControl), new FrameworkPropertyMetadata(null));

    public int myGridSize
    {
        get { return (int)GetValue(myGridSizeProperty); }
        set { SetValue(myGridSizeProperty, value); }
    }

    public SudokuUniGrid()
    {
        InitializeComponent();

        Loaded += SudokuUniGrid_Loaded;
    }

    private void SudokuUniGrid_Loaded(object sender, RoutedEventArgs e)
    {
        Console.WriteLine(myGridSize);

        // build here
    }
}