WPF 数据模板和按钮

WPF Data Templates and Buttons

提问by adondero

Note: I am using Visual Studio 2012

注意：我使用的是 Visual Studio 2012

I have the following DataTemplate (note: there is a TextBlock and Button)

我有以下 DataTemplate（注意：有一个 TextBlock 和 Button）

<DataTemplate DataType="{x:Type ctlDefs:myButton}">
    <StackPanel>
        <TextBlock Text="{Binding LabelText}" Margin="10,0,10,0"/>

        <Button Content="{Binding LabelText}" Margin="0,0,10,0" 
            Width="{Binding ButtonWidth}" 
            Height="35"
            Command="{Binding ButtonCommand}" 
            Visibility="Visible"                    
            />
    </StackPanel>
</DataTemplate>

My screen is dynamically adding controls of myButton to an Items Control

我的屏幕正在将 myButton 的控件动态添加到 Items Control

 <ItemsControl ItemsSource="{Binding CommandButtons, Mode=OneWay}"
               FlowDirection="LeftToRight"
               DockPanel.Dock="Right"
              >

The first time I render the view, the Textblock shows up for each button, but the Button itself does not. If I hide the view and then show it again, the button will appear sometimes (if the CommandButtons list does not change, if it changes, it never shows).

我第一次渲染视图时，每个按钮都会显示 Textblock，但 Button 本身没有。如果我隐藏视图然后再次显示它，按钮有时会出现（如果 CommandButtons 列表没有改变，如果它改变了，它永远不会显示）。

After rendering the view, I looked in the Output window and no binding errors.

渲染视图后，我查看了输出窗口，没有绑定错误。

What am I missing.

我错过了什么。

回答by failedprogramming

I've knocked up a quick application to work with your sample code and didn't seem to have any issues with the view. Below is what it looks like when run.

我已经找到了一个快速应用程序来处理您的示例代码，并且视图似乎没有任何问题。下面是运行时的样子。

I've included my code below in case it helps. Note: I didn't add a real ICommand object for brevity and I accidentally named the MyButton class with capital M instead of small m like your example

我在下面包含了我的代码，以防万一。注意：为简洁起见，我没有添加真正的 ICommand 对象，而且我不小心将 MyButton 类命名为大写 M 而不是像您的示例一样的小 m

ViewModelBase.cs

视图模型库.cs

public abstract class ViewModelBase : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    protected void OnPropertyChanged(string propertyName)
    {
        this.OnPropertyChanged(new PropertyChangedEventArgs(propertyName));
    }

    protected virtual void OnPropertyChanged(PropertyChangedEventArgs e)
    {
        var handler = this.PropertyChanged;
        if (handler != null)
        {
            handler(this, e);
        }
    }
}

public class MainWindowViewModel : ViewModelBase
{
    public MainWindowViewModel()
    {
        this.CommandButtons = new ObservableCollection<MyButton>();
    }
    public ObservableCollection<MyButton> CommandButtons { get; private set; }
}

App.xaml.cs

应用程序.xaml.cs

public partial class App : Application
{
    protected override void OnStartup(StartupEventArgs e)
    {
        base.OnStartup(e);

        var mainvm = new MainWindowViewModel();
        var window = new MainWindow
        {
            DataContext = mainvm
        };
        window.Show();

        mainvm.CommandButtons.Add(new MyButton { ButtonWidth = 50, LabelText = "Button 1" });
        mainvm.CommandButtons.Add(new MyButton { ButtonWidth = 50, LabelText = "Button 2" });
        mainvm.CommandButtons.Add(new MyButton { ButtonWidth = 50, LabelText = "Button 3" });
    }
}

MainWindow.xaml

主窗口.xaml

<Window x:Class="WpfApplication1.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:ctlDefs="clr-namespace:WpfApplication1"
    Title="MainWindow" Height="350" Width="525">
<Window.Resources>
    <DataTemplate DataType="{x:Type ctlDefs:MyButton}">
        <StackPanel>
            <TextBlock Text="{Binding LabelText}" Margin="10,0,10,0"/>

            <Button Content="{Binding LabelText}" Margin="0,0,10,0" 
                    Width="{Binding ButtonWidth}" 
                    Height="35"
                    Command="{Binding ButtonCommand}" 
                    Visibility="Visible"                    
        />
        </StackPanel>
    </DataTemplate>
</Window.Resources>
<Grid>
    <ItemsControl ItemsSource="{Binding CommandButtons, Mode=OneWay}"
           FlowDirection="LeftToRight"
           DockPanel.Dock="Right"
          />
</Grid>

MyButton.cs

MyButton.cs

public class MyButton : ViewModelBase
{
    private string _labelText;

    public string LabelText
    {
        get { return this._labelText; }
        set { this._labelText = value; this.OnPropertyChanged("LabelText"); }
    }

    private double _buttonWidth;

    public double ButtonWidth
    {
        get { return _buttonWidth; }
        set { _buttonWidth = value; this.OnPropertyChanged("ButtonWidth"); }
    }

    private ICommand _buttonCommand;

    public ICommand ButtonCommand
    {
        get { return _buttonCommand; }
        set { _buttonCommand = value; this.OnPropertyChanged("ButtonCommand"); }
    }
}