c# - 不使用代码隐藏从文本框中删除 'None'

Question

我有一个使用多重绑定(bind)生成的运输标签，如下所示:

<TextBox x:Name="TextBoxShippingLabel" Margin="0,10,-2,2" TextWrapping="Wrap">
    <TextBox.Text>
        <MultiBinding StringFormat="{}{0} {1}&#x0a;{2}&#x0a;{3}&#x0a;{4}&#x0a;{5}&#x0a;{6} {7}">
            <Binding ElementName="dataGridOutstandingOrders" Path="SelectedItem[FirstName]" />
            <Binding ElementName="dataGridOutstandingOrders" Path="SelectedItem[Surname]" />
            <Binding ElementName="dataGridOutstandingOrders" Path="SelectedItem[Department]" />
            <Binding ElementName="dataGridOutstandingOrders" Path="SelectedItem[Organisation]" />
            <Binding ElementName="dataGridOutstandingOrders" Path="SelectedItem[Street]" />
            <Binding ElementName="dataGridOutstandingOrders" Path="SelectedItem[Suburb]" />
            <Binding ElementName="dataGridOutstandingOrders" Path="SelectedItem[State]" />
            <Binding ElementName="dataGridOutstandingOrders" Path="SelectedItem[Postcode]" />
        </MultiBinding>
    </TextBox.Text>
</TextBox>

这很好用，除非组织或部门等数据返回为“无”(这发生在个人下达的订单的情况下)。当发生这种情况时，标签表示如下:

有没有一种方法可以使用 XAML 来识别绑定(bind)何时返回“无”并使用备用 StringFormat？

Answer 1

我遇到了同样的问题，我使用了转换器。简单干净:

  <MultiBinding Converter="{StaticResource TextAlternateConverter}">

public class TextAlternateConverter: IMultiValueConverter
{
    public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {

      StringBuilder myOutputText = new StringBuilder();

        foreach (string param in values)
        {
            if (param == "None")
                myOutputText.Append("Give alternate text");
            else
                myOutputText.Append(param);
        }

        return myOutputText.ToString();
    }

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new System.NotImplementedException();
    }
}