Question

I have multiple large objects which each have about 60 strings. I have to trim all those strings, and I’d like to do so without having to go this.mystring = this.mystring.Trim(). Instead, I’m looking for a way to automatically have each object discover its own strings and then perform the operation.

I know a little bit about reflection, but not enough, but I think this is possible?

Also, I’m not sure if this matters, but some string properties are read-only (only have a getter), so those properties would have to be skipped.

Help?

Answer 1

Well, it’s easy enough to get all the properties, and find out which ones are strings and writable. LINQ makes it even easier.

var props = instance.GetType()
                    .GetProperties(BindingFlags.Instance | BindingFlags.Public)
                    // Ignore non-string properties
                    .Where(prop => prop.PropertyType == typeof(string))
                    // Ignore indexers
                    .Where(prop => prop.GetIndexParameters().Length == 0)
                    // Must be both readable and writable
                    .Where(prop => prop.CanWrite && prop.CanRead);

foreach (PropertyInfo prop in props)
{
    string value = (string) prop.GetValue(instance, null);
    if (value != null)
    {
        value = value.Trim();
        prop.SetValue(instance, value, null);
    }
}

You may want to only set the property if trimming actually makes a difference, to avoid redundant computations for complex properties – or it may not be an issue for you.

There are various ways of improving the performance if necessary – things like:

• Simply caching the relevant properties for each type
• Using Delegate.CreateDelegate to build delegates for the getters and setters
• Possibly using expression trees, although I’m not sure whether they’d help here

I wouldn’t take any of those steps unless performance is actually a problem though.