Generic Method - Iterate through a generic type

Question

I have a generic method which I pass an object of a certain type. This object incorporates IEnumerable and IEnumerator in order to allow iteration using foreach, however when I try to iterate it which in the generic method i gives me this error >> "foreach statement cannot operate on variables of type 'T' because 'T' does not contain a public definition for 'GetEnumerator''

Here is my code:

        private bool GenericSummaryResultComparison<T>(string szRiskRecordFilePath, string szResultSetSchemaFilePath) where T : class
        {
            try
            {
                T oRiskRecord;

//Read in the result files.
oRiskRecord = SerializationMethods.DeserializeIt<T>(szResultFilePath1, szResultSetSchemaFilePath);

                foreach (T o in oRiskRecord)
                {
                    // actions
                }

                return true;
            }
            catch (Exception ex)
            {
                throw new ArgumentException(ex.Message, ex.InnerException);
            }
        }

How can I get this iteration to work?

Thanks

Praneeth Kumar · Answer

Did you try putting a break point in line below and check whether oRiskRecord is of type RiskRecord itself? oRiskRecord = SerializationMethods.DeserializeIt (szResultFilePath1 szResultSetSchemaFilePath);

Mark Maguire · Answer

Apologies I do incorporate the GetEnumerator. I accidentally did not include it. It still has the problem even with the GetEnumerator code in it. Thanks Mark

Praneeth Kumar · Answer

Try this public class RiskRecord : ISerializable  IEnumerable { #region Private IEnumerable declarations public RiskRecord [] oRiskRecordElements; #endregion public RiskRecord( RiskRecord [] oArray) { //No contructor code required. //NOTE: This contructor is required for serialization. oRiskRecordElements = oArray; } #region IEnumerable Members public IEnumerator GetEnumerator() { return (IEnumerator)new RiskRecordEnumerator(this); } #endregion public class RiskRecordEnumerator : IEnumerator { private int iPos = -1; private RiskRecord oRiskRecord; public RiskRecordEnumerator( RiskRecord oRiskRecord) { try { this .oRiskRecord = oRiskRecord; } catch ( Exception ex) { throw new ArgumentException (ex.Message ex.InnerException); } } //Declare the MoveNext method as required by the IEnumerator. public bool MoveNext() { try { if (iPos { iPos++; return true ; } else { return false ; } } catch ( Exception ex) { throw new ArgumentException (ex.Message ex.InnerException); } } //Declare the Reset method required by the IEnumerator public void Reset() { iPos = -1; } //Declare the Current property required by the IEnumerator public object Current { get { return oRiskRecord.oRiskRecordElements[iPos]; } } }

Mark Maguire · Answer

Please see this log: http://www.c-sharpcorner.com/Forums/Thread/126443/iterate-an-object-in-a-generic-method.aspx I accidently submitted this one before i completed it. Let me know if that helps you in anyway. The code below is from the class object representing RiskRecord it shows that I have incorporated IEnumerable and IEnumerator (NOTE: I have removed data properties from the RiskRecord class as it would be too long to include them). public class RiskRecord : ISerializable  IEnumerable { #region Private IEnumerable declarations public RiskRecord [] oRiskRecordElements; #endregion public RiskRecord( RiskRecord [] oArray) { //No contructor code required. //NOTE: This contructor is required for serialization. oRiskRecordElements = oArray; } public class RiskRecordEnumerator : IEnumerator { private int iPos = -1; private RiskRecord oRiskRecord; public RiskRecordEnumerator( RiskRecord oRiskRecord) { try { this .oRiskRecord = oRiskRecord; } catch ( Exception ex) { throw new ArgumentException (ex.Message ex.InnerException); } } //Declare the MoveNext method as required by the IEnumerator. public bool MoveNext() { try { if (iPos { iPos++; return true ; } else { return false ; } } catch ( Exception ex) { throw new ArgumentException (ex.Message ex.InnerException); } } //Declare the Reset method required by the IEnumerator public void Reset() { iPos = -1; } //Declare the Current property required by the IEnumerator public object Current { get { return oRiskRecord.oRiskRecordElements[iPos]; } } } Thanks Mark

Praneeth Kumar · Answer

foreach (T o in oRiskRecord) { // actions } In this line it throws error because oRiskRecord is not of type collection which is implementing IEnumerator. Can you post any sample project if you have? Regards Praneeth

Jaganathan Bantheswaran · Answer

Hi Instead of T use var.