将对象投射到 T [英] Cast object to T

问题描述

我正在使用 .NET 中的 XmlReader 类解析 XML 文件，我认为编写一个通用的解析函数来通用地读取不同的属性会很聪明.我想出了以下功能:

I'm parsing an XML file with the XmlReader class in .NET and I thought it would be smart to write a generic parse function to read different attributes generically. I came up with the following function:

private static T ReadData<T>(XmlReader reader, string value)
{
    reader.MoveToAttribute(value);
    object readData = reader.ReadContentAsObject();
    return (T)readData;
}

我意识到，这并不完全按照我的计划进行；它会抛出诸如 int 或 double 之类的原始类型的错误，因为强制转换无法从 string 转换为数字类型.有什么办法可以让我的函数以修改后的形式占上风?

As I came to realise, this does not work entirely as I have planned; it throws an error with primitive types such as int or double, since a cast cannot convert from a string to a numeric type. Is there any way for my function to prevail in modified form?

推荐答案

首先检查是否可以强制转换.

First check to see if it can be cast.

if (readData is T) {
    return (T)readData;
} 
try {
   return (T)Convert.ChangeType(readData, typeof(T));
} 
catch (InvalidCastException) {
   return default(T);
}

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