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如何在NVelocity中捕获InvalidReference错误

nvelocity .net c#

5

Peter Starbek · 技术社区 · 16 年前

我正在使用codeplex 模板引擎

我怎样才能得到这个?

IInvalidReferenceEventHandler 接口位于NVelocity.App.Event命名空间中,但我找不到如何使用它的任何信息。任何帮助都将不胜感激。

1 回复 | 直到 16 年前

1

3

Peter Starbek 16 年前

我找到了解决办法。

我创建了EventHandler类:

public class NVelocityEventHandler : IInvalidReferenceEventHandler, IMethodExceptionEventHandler
{
        #region IInvalidReferenceEventHandler Members

        public object InvalidGetMethod(NVelocity.Context.IContext context, string reference, object object_Renamed, string property, NVelocity.Util.Introspection.Info info)
        {
            return "InvalidGetMethod:" + reference;
        }

        public object InvalidMethod(NVelocity.Context.IContext context, string reference, object object_Renamed, string method, NVelocity.Util.Introspection.Info info)
        {
            return "InvalidMethod:" + reference;
        }

        public bool InvalidSetMethod(NVelocity.Context.IContext context, string leftreference, string rightreference, NVelocity.Util.Introspection.Info info)
        {
            return true;
        }

        #endregion

        #region IMethodExceptionEventHandler Members

        object IMethodExceptionEventHandler.MethodException(Type claz, string method, Exception e)
        {
            return "MethodException:" + method;
        }

        #endregion 
}

然后我在下面的代码中使用它:

StringWriter writer = new StringWriter();
NVelocity.App.VelocityEngine eng = new NVelocity.App.VelocityEngine();
try
{
    NVelocityEventHandler te = new NVelocityEventHandler();
    EventCartridge ec = new EventCartridge();
    ec.AddEventHandler(te);
    VelocityContext vc = new VelocityContext((IDictionary)parameters);
    ec.AttachToContext(vc);
    eng.Evaluate(vc, writer, "templatestring", template);
}
catch (ParseErrorException pe)
{
    return pe.Message;
}
catch (MethodInvocationException mi)
{
    return mi.Message;
}