在ASP.NET C#中，可以使用反射来将源对象的属性映射到目标对象。下面是一个示例代码：

using System;
using System.Reflection;

public class SourceObject
{
    public int Id { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }
}

public class TargetObject
{
    public int Id { get; set; }
    public string Name { get; set; }
}

public static class Mapper
{
    public static void MapProperties(object source, object target)
    {
        Type sourceType = source.GetType();
        Type targetType = target.GetType();

        PropertyInfo[] sourceProperties = sourceType.GetProperties();
        PropertyInfo[] targetProperties = targetType.GetProperties();

        foreach (PropertyInfo sourceProperty in sourceProperties)
        {
            PropertyInfo targetProperty = Array.Find(targetProperties, p => p.Name == sourceProperty.Name);

            if (targetProperty != null && targetProperty.PropertyType == sourceProperty.PropertyType)
            {
                object value = sourceProperty.GetValue(source);
                targetProperty.SetValue(target, value);
            }
        }
    }
}

public class Program
{
    public static void Main()
    {
        SourceObject source = new SourceObject()
        {
            Id = 1,
            Name = "Test",
            Description = "Sample description"
        };

        TargetObject target = new TargetObject();

        Mapper.MapProperties(source, target);

        Console.WriteLine("Id: " + target.Id);
        Console.WriteLine("Name: " + target.Name);
    }
}

在上面的示例中，SourceObject是源对象，TargetObject是目标对象。Mapper类中的MapProperties方法使用反射来将源对象的属性映射到目标对象。在Main方法中，创建了一个源对象和一个目标对象，并使用MapProperties方法将源对象的属性映射到目标对象。最后打印目标对象的属性值。

注意，这只是一个简单的示例，实际应用中可能需要处理更复杂的映射逻辑和异常情况。