Get property value from string using reflection in C#

I am trying implement the Data transformation using Reflection1 example in my code.

The GetSourceValue function has a switch comparing various types, but I want to remove these types and properties and have GetSourceValue get the value of the property using only a single string as the parameter. I want to pass a class and property in the string and resolve the value of the property.

Is this possible?

1 Web Archive version of original blog post

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 public static object GetPropValue(object src, string propName)
 {
     return src.GetType().GetProperty(propName).GetValue(src, null);
 }

当然，你会想添加验证和什么，但这是它的要点。

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How about something like this:

public static Object GetPropValue(this Object obj, String name) {
    foreach (String part in name.Split('.')) {
        if (obj == null) { return null; }

        Type type = obj.GetType();
        PropertyInfo info = type.GetProperty(part);
        if (info == null) { return null; }

        obj = info.GetValue(obj, null);
    }
    return obj;
}

public static T GetPropValue<T>(this Object obj, String name) {
    Object retval = GetPropValue(obj, name);
    if (retval == null) { return default(T); }

    // throws InvalidCastException if types are incompatible
    return (T) retval;
}

This will allow you to descend into properties using a single string, like this:

DateTime now = DateTime.Now;
int min = GetPropValue<int>(now, "TimeOfDay.Minutes");
int hrs = now.GetPropValue<int>("TimeOfDay.Hours");

You can either use these methods as static methods or extensions.

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Add to any Class :

public class Foo
{
    public object this[string propertyName]
    {
        get { return this.GetType().GetProperty(propertyName).GetValue(this, null); }
        set { this.GetType().GetProperty(propertyName).SetValue(this, value, null); }
    }

    public string Bar { get; set; }
}

Then, you can use as:

Foo f = new Foo();
// Set
f["Bar"] = "asdf";
// Get
string s = (string)f["Bar"];

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