Question

我希望复制一个绑定，这样我就可以在其上设置不同的源属性而不会影响原始绑定。这只是将新绑定的所有属性设置为与旧的相同的情况吗？

Answer 1

以下是我解决问题的方法：

public static BindingBase CloneBinding(BindingBase bindingBase, object source)
{
    var binding = bindingBase as Binding;
    if (binding != null)
    {
        var result = new Binding
                         {
                             Source = source,
                             AsyncState = binding.AsyncState,
                             BindingGroupName = binding.BindingGroupName,
                             BindsDirectlyToSource = binding.BindsDirectlyToSource,
                             Converter = binding.Converter,
                             ConverterCulture = binding.ConverterCulture,
                             ConverterParameter = binding.ConverterParameter,
                             //ElementName = binding.ElementName,
                             FallbackValue = binding.FallbackValue,
                             IsAsync = binding.IsAsync,
                             Mode = binding.Mode,
                             NotifyOnSourceUpdated = binding.NotifyOnSourceUpdated,
                             NotifyOnTargetUpdated = binding.NotifyOnTargetUpdated,
                             NotifyOnValidationError = binding.NotifyOnValidationError,
                             Path = binding.Path,
                             //RelativeSource = binding.RelativeSource,
                             StringFormat = binding.StringFormat,
                             TargetNullValue = binding.TargetNullValue,
                             UpdateSourceExceptionFilter = binding.UpdateSourceExceptionFilter,
                             UpdateSourceTrigger = binding.UpdateSourceTrigger,
                             ValidatesOnDataErrors = binding.ValidatesOnDataErrors,
                             ValidatesOnExceptions = binding.ValidatesOnExceptions,
                             XPath = binding.XPath,
                         };

        foreach (var validationRule in binding.ValidationRules)
        {
            result.ValidationRules.Add(validationRule);
        }

        return result;
    }

    var multiBinding = bindingBase as MultiBinding;
    if (multiBinding != null)
    {
        var result = new MultiBinding
                         {
                             BindingGroupName = multiBinding.BindingGroupName,
                             Converter = multiBinding.Converter,
                             ConverterCulture = multiBinding.ConverterCulture,
                             ConverterParameter = multiBinding.ConverterParameter,
                             FallbackValue = multiBinding.FallbackValue,
                             Mode = multiBinding.Mode,
                             NotifyOnSourceUpdated = multiBinding.NotifyOnSourceUpdated,
                             NotifyOnTargetUpdated = multiBinding.NotifyOnTargetUpdated,
                             NotifyOnValidationError = multiBinding.NotifyOnValidationError,
                             StringFormat = multiBinding.StringFormat,
                             TargetNullValue = multiBinding.TargetNullValue,
                             UpdateSourceExceptionFilter = multiBinding.UpdateSourceExceptionFilter,
                             UpdateSourceTrigger = multiBinding.UpdateSourceTrigger,
                             ValidatesOnDataErrors = multiBinding.ValidatesOnDataErrors,
                             ValidatesOnExceptions = multiBinding.ValidatesOnDataErrors,
                         };

        foreach (var validationRule in multiBinding.ValidationRules)
        {
            result.ValidationRules.Add(validationRule);
        }

        foreach (var childBinding in multiBinding.Bindings)
        {
            result.Bindings.Add(CloneBinding(childBinding, source));
        }

        return result;
    }

    var priorityBinding = bindingBase as PriorityBinding;
    if (priorityBinding != null)
    {
        var result = new PriorityBinding
                         {
                             BindingGroupName = priorityBinding.BindingGroupName,
                             FallbackValue = priorityBinding.FallbackValue,
                             StringFormat = priorityBinding.StringFormat,
                             TargetNullValue = priorityBinding.TargetNullValue,
                         };

        foreach (var childBinding in priorityBinding.Bindings)
        {
            result.Bindings.Add(CloneBinding(childBinding, source));
        }

        return result;
    }

    throw new NotSupportedException("Failed to clone binding");
}

Answer 2

如果找不到方法，则已经为Binding创建了一个扩展名。

    public static class BindingExtensions
{
    public static Binding Clone(this Binding binding)
    {
        var cloned = new Binding();
        //copy properties here
        return cloned;
    }
}

public void doWork()
{
    Binding b= new Binding();
    Binding nb = b.Clone(); 
}

Answer 3

我刚刚注意到在BindingBase反编译代码中它有一个内部Clone()方法，所以另一个（不安全，不要在家尝试，使用风险等等）解决方案是使用反射来绕过编译器的访问限制：

public static BindingBase CloneBinding(BindingBase bindingBase, BindingMode mode = BindingMode.Default)
{
    var cloneMethodInfo = typeof(BindingBase).GetMethod("Clone", BindingFlags.Instance | BindingFlags.NonPublic);
    return (BindingBase) cloneMethodInfo.Invoke(bindingBase, new object[] { mode });
}

但是没试过，所以它可能不起作用。

Answer 4

我刚刚开始使用它。到目前为止，它并不是最有效的，但足够快。它很简单，理论上也不应错过任何特性。

using System.IO;
using System.Windows.Data;
using System.Windows.Markup;
using System.Xml;

static Binding CloneBinding(Binding binding)
{
    var xaml = XamlWriter.Save(binding);
    var stringReader = new StringReader(xaml);
    var xmlReader = XmlReader.Create(stringReader);
    return (Binding)XamlReader.Load(xmlReader);
}

受到另一个问题的answer的启发。

绑定没有克隆方法，是一种有效的复制方法

4 个答案: