/// <summary>
///
/// <param name="param">ParameterExpression that points to "x=>" parameter</param>
/// <param name="part">part of the lambda rule like "x.Id = 1"</param>
/// <returns></returns>
private BinaryExpression GetRuleExpression(ParameterExpression param, string part)
{
var partMatch = rulePartRegex.Match(part);
if (partMatch.Success)
{
Type tType = typeof(T);
string fieldName = partMatch.Groups[1].Value.Replace("(", string.Empty).Replace(param.Name + ".", string.Empty).Trim();
//var fieldNameParts = fieldName.Split('.');
//fieldName = fieldNameParts[fieldNameParts.Length - 1];
string compareOperator = partMatch.Groups[2].Value.Trim();
string compareTo = partMatch.Groups[3].Value.Replace(")", string.Empty).Trim();
if (compareTo.StartsWith("\"") && compareTo.EndsWith("\""))
{
compareTo = compareTo.Substring(1, compareTo.Length - 2);
}
System.Reflection.MemberInfo memberInfo = null;
var fieldNameParts = fieldName.Split('.');
string memberStrName = fieldNameParts[fieldNameParts.Length - 1];
foreach (var interfType in tType.GetInterfaces())
{
var memberInfos = interfType.GetMember(memberStrName, System.Reflection.BindingFlags.FlattenHierarchy | System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.Public);
if (memberInfos.Length > 0)
{
memberInfo = memberInfos[0]; //CONSIDER: multiple fields can be found
}
}
if (memberInfo == null)
{
var memberInfos = tType.GetMember(memberStrName, System.Reflection.BindingFlags.FlattenHierarchy | System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.Public);
if (memberInfos.Length > 0)
{
memberInfo = memberInfos[0]; //CONSIDER: multiple fields can be found
}
}
if (memberInfo == null)
{
throw new Xxception(string.Format("Type '{0}' do not expose member named '{1}'", tType.FullName, memberStrName));
}
Type compareToType = memberInfo.GetReturnType();
var lhs = Expression.MakeMemberAccess(param, memberInfo);
ConstantExpression rhs;
if (string.IsNullOrEmpty(compareTo) && compareToType.IsValueType)
{
var val = Activator.CreateInstance(compareToType);
rhs = Expression.Constant(val);
}
else
{
//if (compareToType.GenericTypeArguments != null && compareToType.GenericTypeArguments.Length == 1) //Nullable type
//{
// var underlyingType = compareToType.GenericTypeArguments[0];
// var val = Convert.ChangeType(compareTo, underlyingType);
// rhs = Expression.Constant(val);
//}
//else
//{
// var val = Convert.ChangeType(compareTo, compareToType);
// rhs = Expression.Constant(val);
//}
var val = ChangeType(compareTo, compareToType);
rhs = Expression.Constant(val);
}
return(GetCompareExpression(compareOperator, lhs, rhs));
}
throw new Xxception(string.Format("Unable to parse lambda expression {0}", part));
}
