SL4.基本数据验证

XAML：

  <StackPanel>
            <Button Name="MyButton" Content="Update"  Click="MyButton_Click"  Width="65" Height="41"></Button>
            <TextBlock Height="23" Name="tbtitle" Text="{Binding Title,Mode=OneTime}" />
            <TextBlock Height="23" Name="tbtitles" Text="{Binding Title,Mode=OneWay}" />
            <TextBox Height="23" Name="tbprice" Text="{Binding Path= Price,Mode=TwoWay,ValidatesOnDataErrors=True}"
                   Width="150"/>
 </StackPanel>

　

Book.CS:

        private decimal _price;
        public decimal Price
        {
            get
            {
                return _price;
            }
            set
            {
                if (_price != value)
                {
                    if (value<0)
                    {
                        _dataErrors["Price"] = "价钱不能小于0";
                    }
                    else
                    {
                        if (_dataErrors.ContainsKey("Price"))
                        {
                            _dataErrors.Remove("Price");
                        }
                    }
                    _price = value;
                    if (PropertyChanged != null)
                    {
                        PropertyChanged(this, new PropertyChangedEventArgs("Price"));
                    }
                }
            }
        }

        private string _dataError = string.Empty;
        public string Error
        {
            get { return _dataError; }
        }

        private Dictionary<string, string> _dataErrors = new Dictionary<string, string>();
        public string this[string columnName]
        {
            get
            {
                if (_dataErrors.ContainsKey(columnName))
                    return _dataErrors[columnName];
                else
                    return null;
            }
        }