Question

I’m trying to use a lambda expression to remove a certain object from a list, based on a value within that object. Here is my lambda:

ChartAttributes.ToList().RemoveAll(a => a.AttributeValue.Contains("PILOT"));

Here is the ChartAttributes list

IList<IChartAttribute> ChartAttributes 

Here is the object ChartAttribute contained within the above list

    public virtual string AttributeKey { get; set; }       
    public virtual string AttributeValue { get; set; }        
    public virtual int ChartAttributeId { get; set; }        
    public virtual int ChartSpecificationId { get; set; }

There is a chart attribute with its AttributeKey set to “PILOT”. But this never gets removed. What am I doing wrong?

Thanks

Answer 1

Your code is taking an IEnumerable, copying all of its elements into a list and then removing items from that copy. The source IEnumerable is not modified.

Try this:

var list =  ChartAttributes.ToList();
list.RemoveAll(a => a.AttributeValue.Contains("PILOT"));
ChartAttributes = list;

EDIT

Actually a better way, without needing to call ToList:

ChartAttributes = ChartAttributes.Where(a => !a.AttributeValue.Contains("PILOT"));