Generic type conversion FROM string

Question

I have a class that I want to use to store \"properties\" for another class. These properties simply have a name and a value. Ideally, what I would like is to be able to add

Answer 1

With inspiration from the Bob's answer, these extensions also support null value conversion and all primitive conversion back and fourth.

public static class ConversionExtensions
{
        public static object Convert(this object value, Type t)
        {
            Type underlyingType = Nullable.GetUnderlyingType(t);

            if (underlyingType != null && value == null)
            {
                return null;
            }
            Type basetype = underlyingType == null ? t : underlyingType;
            return System.Convert.ChangeType(value, basetype);
        }

        public static T Convert<T>(this object value)
        {
            return (T)value.Convert(typeof(T));
        }
}

Examples

            string stringValue = null;
            int? intResult = stringValue.Convert<int?>();

            int? intValue = null;
            var strResult = intValue.Convert<string>();

Answer 2

You could possibly use a construct such as a traits class. In this way, you would have a parameterised helper class that knows how to convert a string to a value of its own type. Then your getter might look like this:

get { return StringConverter<DataType>.FromString(base.Value); }

Now, I must point out that my experience with parameterised types is limited to C++ and its templates, but I imagine there is some way to do the same sort of thing using C# generics.

Answer 3

I used lobos answer and it works. But I had a problem with the conversion of doubles because of the culture settings. So I added

return (T)Convert.ChangeType(base.Value, typeof(T), CultureInfo.InvariantCulture);

Answer 4

TypeDescriptor.GetConverter(PropertyObject).ConvertFrom(Value)

TypeDescriptor is class having method GetConvertor which accept a Type object and then you can call ConvertFrom method to convert the value for that specified object.

Answer 5

I am not sure whether I understood your intentions correctly, but let's see if this one helps.

public class TypedProperty<T> : Property where T : IConvertible
{
    public T TypedValue
    {
        get { return (T)Convert.ChangeType(base.Value, typeof(T)); }
        set { base.Value = value.ToString();}
    }
}

Answer 6

For many types (integer, double, DateTime etc), there is a static Parse method. You can invoke it using reflection:

MethodInfo m = typeof(T).GetMethod("Parse", new Type[] { typeof(string) } );

if (m != null)
{
    return m.Invoke(null, new object[] { base.Value });
}