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Setting a property by reflection with a string value

Asked 2009-07-06T20:43:19.247
373

I'd like to set a property of an object through Reflection, with a value of type string. So, for instance, suppose I have a Ship class, with a property of Latitude, which is a double.

Here's what I'd like to do:

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:

Object of type 'System.String' cannot be converted to type 'System.Double'.

How can I convert value to the proper type, based on propertyInfo?

c# reflection type-conversion propertyinfo setvalue
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2 Answers

37

As several others have said, you want to use Convert.ChangeType:

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

In fact, I recommend you look at the entire Convert Class.

This class, and many other useful classes are part of the System Namespace. I find it useful to scan that namespace every year or so to see what features I've missed. Give it a try!

answered 2009-07-06T20:44:54.237
3

Or you could try:

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

//But this will cause problems if your string value IsNullOrEmplty...
answered 2009-07-06T20:47:37.507

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