如何在用户键入文本框时启用按钮

Question

Button在用户输入内容时,WPF中最简单的方法是TextBox什么？

Answer 1

为什么每个人都这么复杂!

    <TextBox x:Name="TB"/>
    <Button IsEnabled="{Binding ElementName=TB,Path=Text.Length}">Test</Button>

没有别的......

Answer 2

使用简单命令

<TextBox Text={Binding Path=TitleText}/>

<Button Command="{Binding Path=ClearTextCommand}" Content="Clear Text"/>

这是视图模型中的示例代码

public class MyViewModel : INotifyPropertyChanged
{
    public ICommand ClearTextCommand { get; private set; }

    private string _titleText; 
    public string TitleText
    {
        get { return _titleText; }
        set
        {
            if (value == _titleText)
                return;

            _titleText = value;
            this.OnPropertyChanged("TitleText");
        }
    }   

    public MyViewModel()
    {
        ClearTextCommand = new SimpleCommand
            {
                ExecuteDelegate = x => TitleText="",
                CanExecuteDelegate = x => TitleText.Length > 0
            };  
    }            

    public event PropertyChangedEventHandler PropertyChanged;

    protected void OnPropertyChanged(string propertyName)
    {
        PropertyChangedEventHandler handler = this.PropertyChanged;
        if (handler != null)
            handler(this, new PropertyChangedEventArgs(propertyName));
    }     
}

有关详细信息，请参阅 Marlon Grechs SimpleCommand

另请查看http://blogs.msdn.com/llobo/archive/2009/05/01/download-mv-vm-project-template-toolkit.aspx中的 MVVM 项目模板/工具包。它使用 DelegateCommand 进行命令，对于任何项目来说它都应该是一个很好的起始模板。