通过反射使用字符串值设置属性

本文翻译自：Setting a property by reflection with a string value

I'd like to set a property of an object through Reflection, with a value of type string . 我想通过Reflection设置对象的属性，其值为string类型。 So, for instance, suppose I have a Ship class, with a property of Latitude , which is a double . 因此，例如，假设我有一个Ship类，其属性为Latitude ，这是一个double 。

Here's what I'd like to do: 这是我想做的事情：

Ship ship = new Ship();
string value = "5.5";
PropertyInfo propertyInfo = ship.GetType().GetProperty("Latitude");
propertyInfo.SetValue(ship, value, null);

As is, this throws an ArgumentException : 原样，这会抛出ArgumentException ：

Object of type 'System.String' cannot be converted to type 'System.Double'. “System.String”类型的对象无法转换为“System.Double”类型。

How can I convert value to the proper type, based on propertyInfo ? 如何根据propertyInfo将值转换为正确的类型？

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#1楼

参考：https://stackoom.com/question/4ZKV/通过反射使用字符串值设置属性

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#2楼

As several others have said, you want to use Convert.ChangeType : 正如其他几个人所说，你想使用Convert.ChangeType ：

propertyInfo.SetValue(ship,
    Convert.ChangeType(value, propertyInfo.PropertyType),
    null);

In fact, I recommend you look at the entire Convert Class . 实际上，我建议你看看整个Convert类 。

This class, and many other useful classes are part of the System Namespace . 此类和许多其他有用的类是System Namespace的一部分。 I find it useful to scan that namespace every year or so to see what features I've missed. 我发现每年扫描一个命名空间很有用，看看我错过了哪些功能。 Give it a try! 试试看！

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#3楼

You can use Convert.ChangeType() - It allows you to use runtime information on any IConvertible type to change representation formats. 您可以使用Convert.ChangeType() - 它允许您使用任何IConvertible类型的运行时信息来更改表示格式。 Not all conversions are possible, though, and you may need to write special case logic if you want to support conversions from types that are not IConvertible . 但是，并非所有转换都是可能的，如果您希望支持非IConvertible类型的转换，则可能需要编写特殊情况逻辑。

The corresponding code (without exception handling or special case logic) would be: 相应的代码（无异常处理或特殊情况逻辑）将是：

Ship ship = new Ship();
string value = "5.5";
PropertyInfo propertyInfo = ship.GetType().GetProperty("Latitude");
propertyInfo.SetValue(ship, Convert.ChangeType(value, propertyInfo.PropertyType), null);

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#4楼

Or you could try: 或者你可以尝试：

propertyInfo.SetValue(ship, Convert.ChangeType(value, propertyInfo.PropertyType), null);

//But this will cause problems if your string value IsNullOrEmplty...

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#5楼

You're probably looking for the Convert.ChangeType method. 您可能正在寻找Convert.ChangeType方法。 For example: 例如：

Ship ship = new Ship();
string value = "5.5";
PropertyInfo propertyInfo = ship.GetType().GetProperty("Latitude");
propertyInfo.SetValue(ship, Convert.ChangeType(value, propertyInfo.PropertyType), null);

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#6楼

Using Convert.ChangeType and getting the type to convert from the PropertyInfo.PropertyType . 使用Convert.ChangeType并从PropertyInfo.PropertyType获取要转换的类型。

propertyInfo.SetValue( ship,
                       Convert.ChangeType( value, propertyInfo.PropertyType ),
                       null );