CrmService Class 代码，提供基本CRUD，以及RetrieveOptionSet、RetrieveAttribute、GetPickListValue等方法

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Xrm.Sdk.Client;
using Microsoft.Xrm.Sdk;
using Microsoft.Xrm.Sdk.Query;
using Microsoft.Xrm.Sdk.Messages;
using Microsoft.Xrm.Sdk.Metadata;

namespace MyNameSpace
{
    public class CrmService
    {
        private IOrganizationService _service;
        public IOrganizationService Default
        {
            get { return _service; }
        }

        public CrmService(IOrganizationService service)
        {
            _service = service;
        }

        public Entity RetrieveByQuery(string entityName, string[] columns, bool activeRecordsOnly, LinkEntity[] linkEntities, params ConditionExpression[] condition)
        {
            QueryExpression qe = new QueryExpression(entityName);
            if (columns.Length > 0)
                qe.ColumnSet = new ColumnSet(columns);
            else
                qe.ColumnSet.AllColumns = true;
            if (null != condition)
                qe.Criteria.Conditions.AddRange(condition);
            if (activeRecordsOnly)
                qe.Criteria.AddCondition("statecode", ConditionOperator.Equal, 0);
            if (null!=linkEntities)
                qe.LinkEntities.AddRange(linkEntities);
            EntityCollection entityCollect = (EntityCollection)Default.RetrieveMultiple(qe);
            if (entityCollect.Entities.Count > 0)
            {
                return entityCollect.Entities.First();
            }
            else
            {
                return null;
            }
        }

        public Entity RetrieveByQuery(string entityName, ColumnSet columns, bool activeRecordsOnly, LinkEntity[] linkEntities, params ConditionExpression[] conditions)
        {
            QueryExpression qe = new QueryExpression(entityName);
            if (null == columns)
                qe.ColumnSet.AllColumns = true;
            else
                qe.ColumnSet = columns;
            if (null != conditions)
                qe.Criteria.Conditions.AddRange(conditions);
            if (activeRecordsOnly)
                qe.Criteria.AddCondition("statecode", ConditionOperator.Equal, 0);
            if (null!=linkEntities)
                qe.LinkEntities.AddRange(linkEntities);
            EntityCollection entityCollect = (EntityCollection)Default.RetrieveMultiple(qe);
            if (entityCollect.Entities.Count > 0)
            {
                return entityCollect.Entities.First();
            }
            else
            {
                return null;
            }
        }

        public EntityCollection RetrieveMultipleByQuery(string entityName, ColumnSet columns, bool activeRecordsOnly, LinkEntity[] linkEntities, params ConditionExpression[] condition)
        {
            QueryExpression qe = new QueryExpression(entityName);
            if (null == columns)
                qe.ColumnSet.AllColumns = true;
            else
                qe.ColumnSet = columns;
            if (null != condition)
                qe.Criteria.Conditions.AddRange(condition);
            if (activeRecordsOnly)
                qe.Criteria.AddCondition("statecode", ConditionOperator.Equal, 0);
            if (null != linkEntities)
                qe.LinkEntities.AddRange(linkEntities);
            EntityCollection entityCollect = (EntityCollection)Default.RetrieveMultiple(qe);
            return entityCollect;
        }

        public EntityCollection RetrieveMultipleByQuery(string entityName, string[] columns, bool activeRecordsOnly, LinkEntity[] linkEntities, params ConditionExpression[] condition)
        {
            QueryExpression qe = new QueryExpression(entityName);
            qe.ColumnSet = new ColumnSet(columns);
            if (null != condition)
                qe.Criteria.Conditions.AddRange(condition);
            if (activeRecordsOnly)
                qe.Criteria.AddCondition("statecode", ConditionOperator.Equal, 0);
            if (null != linkEntities)
                qe.LinkEntities.AddRange(linkEntities);
            EntityCollection entityCollect = (EntityCollection)Default.RetrieveMultiple(qe);
            return entityCollect;
        }

        public QueryExpression GetQuery(string entityName, ColumnSet columns, bool activeRecordsOnly, LinkEntity[] linkEntities, params ConditionExpression[] condition)
        {
            QueryExpression qe = new QueryExpression(entityName);
            if (null == columns)
                qe.ColumnSet.AllColumns = true;
            else
                qe.ColumnSet = columns;
            if (null != condition)
                qe.Criteria.Conditions.AddRange(condition);
            if (activeRecordsOnly)
                qe.Criteria.AddCondition("statecode", ConditionOperator.Equal, 0);
            if (null != linkEntities)
                qe.LinkEntities.AddRange(linkEntities);
            return qe;
        }

        public EntityMetadata RetrieveEntity(string entityName)
        {
            RetrieveEntityRequest req = new RetrieveEntityRequest();
            req.LogicalName = entityName;
            req.RetrieveAsIfPublished = true;
            RetrieveEntityResponse res = (RetrieveEntityResponse)Default.Execute(req);
            return res.EntityMetadata;
        }

        public OptionSetMetadata RetrieveOptionSet(string optionsetName)
        {
            RetrieveOptionSetRequest req = new RetrieveOptionSetRequest();
            req.Name = optionsetName;
            req.RetrieveAsIfPublished = true;
            RetrieveOptionSetResponse res = (RetrieveOptionSetResponse)Default.Execute(req);
            return res.OptionSetMetadata as OptionSetMetadata;
        }

        public AttributeMetadata RetrieveAttribute(string entityName,string attributeName)
        {
            RetrieveAttributeRequest req = new RetrieveAttributeRequest();
            req.EntityLogicalName = entityName;
            req.LogicalName = attributeName;
            req.RetrieveAsIfPublished = true;
            RetrieveAttributeResponse res = (RetrieveAttributeResponse)Default.Execute(req);
            return res.AttributeMetadata;
        }

        public int GetPickListValueWithPrefix(string entity, string attributeName, string twoDigitValue)
        {
            PicklistAttributeMetadata attr = (PicklistAttributeMetadata)RetrieveAttribute(entity, attributeName);
            OptionMetadata option = new OptionMetadata();
            if (attr != null)
            {
                if (attr.OptionSet != null)
                    option = attr.OptionSet.Options.ToList().Find(o => o.Value.Value.ToString().EndsWith(twoDigitValue));
            }
            else
            {
                throw new InvalidOperationException("Option set not found");
            }
            if (option != null)
            {
                if (option.Value.HasValue)
                    return option.Value.Value;
                else
                    throw new InvalidOperationException("Option " + twoDigitValue + " not found");
            }
            else
            {
                throw new InvalidOperationException("Option " + twoDigitValue + " not found");
            }
        }

        public int GetPickListValue(string entity, string attributeName, string label)
        {
            PicklistAttributeMetadata attr = (PicklistAttributeMetadata)RetrieveAttribute(entity, attributeName);
            OptionMetadata option = new OptionMetadata();
            if (attr != null)
            {
                if (attr.OptionSet != null)
                    option = attr.OptionSet.Options.ToList().Find(o => o.Label.UserLocalizedLabel.Label.ToLower().Equals(label.ToLower()));
            }
            else
            {
                throw new InvalidOperationException("Option set not found");
            }
            if (option != null)
            {
                if (option.Value.HasValue)
                    return option.Value.Value;
                else
                    throw new InvalidOperationException("Option " + label + " not found");
            }
            else
            {
                throw new InvalidOperationException("Option " + label + " not found");
            }
        }
    }
}