如果名称与字段名称不同，如何通过反射获取字段值

Question

I have a class

 [BsonIgnoreExtraElements]
    public class CustomerModel
    {        
        public string BranchID { get; set; }       
        public string BranchName { get; set; }        
        public string ReceiverID { get; set; }
        public string ReceiverName{ get; set; }       

        }

I am writing a filter activity which can validate any field with specific value configured in MongoDB

"Exclude":[{"SourceCol":"Receiver Mode ID","Values":{"Value":["G","8","J"]}}

and written the comparing logic as

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

        public static bool CheckPropertyCompare(CustomerModel customer, Exclude item)
        {
            var propertyValue = GetPropValue(customer, item.SourceCol);
            return item.Values.Value.ToList().Contains(propertyValue);

        }

In this, the Receiver Mode ID from MongoDB is actually looking for ReceiverID and I am stuck as to how can I resolve this issue. The only option I can think of is Key-Value pair collection to fetch the field name. but would like to know if there is any options like Attributes which can ease this process.

TIA

Answer 1

I think you can achieve that with Attributes as you say.

You can create a custom attribute, like this:

internal class MongoDBFieldAttribute : Attribute
{
    public string Field{ get; private set; }

    public MongoDBFieldAttribute(string field)
    {
        this.Field= field;
    }
}

Then in your class:

public class CustomerModel
{        
    ...
    [MongoDBField("ReceiverModeID")]
    public string ReceiverID { get; set; }
}

I think it could be better without spaces, it could be a problem, maybe yo can use a Trim() or similar... or yoy can try [MongoDBField("Receiver Mode ID")], never tried.

Then you can create a method than can relation both, property name and attribute name, for example:

   private Dictionary<string, string> getRelationPropertyAttribute(Type type)

    {
        var dicRelation = new Dictionary<string, string>();

        var properties = type.GetProperties();
        foreach (var property in properties)
        {
            var attributes = property.GetCustomAttributes(inherit: false);

            var customAttributes = attributes
                .AsEnumerable()
                .Where(a => a.GetType() == typeof(MongoDBFieldAttribute));

            if (customAttributes.Count() <= 0)
                continue;

            foreach (var attribute in customAttributes)
            {
                if (attribute is MongoDBFieldAttribute attr) 
                    dicRelation[attr.Field] = property.Name;
            }
        }

        return dicRelation;
    }

Finally, you can play with that dictionary and in your method you can do something like that:

    public static bool CheckPropertyCompare(CustomerModel customer, Exclude item)
    {
        var dicRelation = getRelationPropertyAttribute(typeof(CustomerModel));

        var propertyName = dicRelation[item.SourceCol];
        var propertyValue = GetPropValue(customer, propertyName);
        return item.Values.Value.ToList().Contains(propertyValue);

    }

It´s an idea... Hope it helps.