Speed problems with SetValue, ToType and Reflection

Question

I have a 'speed problem' with a program I'm currently developing. I already have encountered the methods which costs some time.

public void ConvertDataFrameToValueFields()
    {
        List<byte[]> items = new List<byte[]>() { new byte[2], new byte[2], new byte[2], new byte[2] };

        items[0][0] = this.DataBytes[0];
        items[0][1] = this.DataBytes[1];
        items[1][0] = this.DataBytes[2];
        items[1][1] = this.DataBytes[3];
        items[2][0] = this.DataBytes[4];
        items[2][1] = this.DataBytes[5];
        items[3][0] = this.DataBytes[6];
        items[3][1] = this.DataBytes[7];

        int i = 0;
        IEnumerable<PropertyInfo> result = this.determineCanMessageValueFields();

        foreach (var prop in result)
        {
            if (prop.PropertyType == typeof(MessageStatusValueField))
            {
                prop.SetValue(this, new MessageStatusValueField(BitConverter.ToUInt16(items[i], 0), prop.Name, this.UnitType), null);
            }
            else if (prop.PropertyType == typeof(MessageValueField))
            {
                prop.SetValue(this, new MessageValueField(BitConverter.ToUInt16(items[i], 0), prop.Name), null);
            }
            else if (prop.PropertyType == typeof(MessageValueFieldInt32))
            {
                prop.SetValue(this, new MessageValueFieldInt32(BitConverter.ToUInt16(items[i], 0), prop.Name), null);
            }
            else if (prop.PropertyType.GetCustomAttributes(false).Count(x => x.GetType() == typeof(BitmaskValueFieldClass)) > 0)
            {
                var tempField = new MessageValueField(BitConverter.ToUInt16(items[i], 0), prop.Name);
                prop.SetValue(this, Convert.ChangeType(tempField, prop.PropertyType), null);
            }
            i++;
        }
    }




     private IEnumerable<PropertyInfo> determineCanMessageValueFields()
            {
                //Get all properties with the 
                //custom attribute [IsValueField]
                return this.GetType().GetProperties()
                                     .Where(p => p.GetCustomAttributes(false)
                                     .Count(x => x.GetType() == typeof(IsValueField)) > 0)
                                     .OrderBy(x => ((IsValueField)x.GetCustomAttributes(false)[0]).ValueFieldIndex);
            }

 public object ToType(Type conversionType, IFormatProvider provider)
        {
            //...only convert if the conversion type is a BitmaskValueFieldClass
            if (conversionType.GetCustomAttributes(false).Count(x => x.GetType() == typeof(BitmaskValueFieldClass)) == 0)
            {
                throw new NotImplementedException("The conversion is only available for conversion types with the BitmaskValueFieldClass attribute");
            }

            //...create an instance of the conversion type
            var instance = Activator.CreateInstance(conversionType);

            //...go thru each property and set the value
            foreach (var item in instance.GetType().BaseType.GetProperties())
            {
                item.SetValue(instance, this.GetType().GetProperty(item.Name).GetValue(this, null), null);
            }

            return instance;
        }

The method ConvertDataFrameToValueFields() is the sticking point. I know it is because of the prop.SetValue() and the ToType() IConvertible method calls. When I am removing the ConvertDataFrameToValueFields() method I gain the missing time I need to fulfill the project.

Is there a way to improve the whole thing? Problem is that the idea has to be as it is. In the ConvertDataFrameToValueFields() method I have to map the returning DataFrame, the DataBytes array, to the MessageValueField properties of the specific class. I'm getting all containing messagevaluefields by calling the ConvertDataFrameToValueFields().

Answer 1

Style

Based on the naming guidlines method names should use PascalCasing casing.

determineCanMessageValueFields()

Instead of calling Count() and checking if it is greater than 0 you should call Any().

So determineCanMessageValueFields() would become

private IEnumerable<PropertyInfo> determineCanMessageValueFields()
{
    return this.GetType().GetProperties()
                            .Where
                                (p => p.GetCustomAttributes(false)
                                            .Any(x => x.GetType() == typeof(IsValueField))
                                )
                            .OrderBy(x => ((IsValueField)x.GetCustomAttributes(false)[0]).ValueFieldIndex);
}

ConvertDataFrameToValueFields()

The creation of the List<byte[]> is not needed at all. If you increment the i counter by 2 you can just use this.DataBytes for the calling BitConverter.ToUInt16(this.DataBytes,i).

This leads after using Any()instead of Count() > 0 to

public void ConvertDataFrameToValueFields()
{

    int i = 0;

    foreach (var prop in DetermineCanMessageValueFields())
    {
        ushort value = BitConverter.ToUInt16(this.DataBytes, i);

        if (prop.PropertyType == typeof(MessageStatusValueField))
        {
            prop.SetValue(this, new MessageStatusValueField(value, prop.Name, this.UnitType), null);
        }
        else if (prop.PropertyType == typeof(MessageValueField))
        {
            prop.SetValue(this, new MessageValueField(value, prop.Name), null);
        }
        else if (prop.PropertyType == typeof(MessageValueFieldInt32))
        {
            prop.SetValue(this, new MessageValueFieldInt32(value, prop.Name), null);
        }
        else if (prop.PropertyType.GetCustomAttributes(false).Any(x => x.GetType() == typeof(BitmaskValueFieldClass)))
        {
            var tempField = new MessageValueField(value, prop.Name);
            prop.SetValue(this, Convert.ChangeType(tempField, prop.PropertyType), null);
        }

        i += 2;
    }
}

and applying the Any() change to the ToType() method

public object ToType(Type conversionType, IFormatProvider provider)
{

    if (!conversionType.GetCustomAttributes(false).Any(x => x.GetType() == typeof(BitmaskValueFieldClass)))
    {
        throw new NotImplementedException("The conversion is only available for conversion types with the BitmaskValueFieldClass attribute");
    }

    var instance = Activator.CreateInstance(conversionType);

    foreach (var item in instance.GetType().BaseType.GetProperties())
    {
        item.SetValue(instance, this.GetType().GetProperty(item.Name).GetValue(this, null), null);
    }

    return instance;
}  

Comments

Comments should be used to explain why something is done, not what is done. The what part should be done by the code itself.