问题描述

我想实现一个通用的运行时类型转换函数，它使用 .Net TypeConverters 进行转换.

I would like to implement a general purpose runtime type conversion function that makes use .Net TypeConverters to do the conversion.

有谁知道如何查找和调用特定类型的 TypeConverter?

Does anyone know how to how to look up and invoke a TypeConverter for a particular type?

考虑这个 C# 示例:

Consider this C# example:

//
// Convert obj to the type specified by 'toType'.
// 
object ConvertTo(object obj, Type toType)
{
    if (TypeIsEqualOrDerivesFrom(obj.GetType(), toType)) <-- I know how to implement this.
    {
        // The type of obj is the same as the type specified by 'toType' or
        // the type of obj derives from the type specified by 'toType'.
        return obj;
    }

    if (TypeConverterExists(obj.GetType(), toType) <-- How do I implement this?
    {
        // There exists a type convertor that is capable of converting from 
        // the type of obj to the type specified by 'toType'.
        return InvokeTypeConverter(obj, toType); <-- How do I implement this?
    }

    throw new TypeConversionFailedException();
}

推荐答案

    TypeConverter converter = TypeDescriptor.GetConverter(sourceType);
    if(converter.CanConvertTo(destinationType)) {
        return converter.ConvertTo(obj, destinationType);   
    }
    converter = TypeDescriptor.GetConverter(destinationType);
    if(converter.CanConvertFrom(sourceType)) {
        return converter.ConvertFrom(obj);
    }

你也可以看看 Convert.ChangeType(obj, destinationType)

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