public static Func <T, bool> Where <T>(string property, string value, ComparingOperators valueOperator)
{
ParameterExpression param = Expression.Parameter(typeof(T), "x");
MemberExpression member = Expression.Property(param, property);
Type propertyType = member.Type;
TypeConverter converter = TypeDescriptor.GetConverter(propertyType);
var converted = converter.ConvertFrom(value.ToString());
ConstantExpression constant = Expression.Constant(converted);
Expression comparingExpression = default(BinaryExpression);
switch (valueOperator)
{
case ComparingOperators.EqualOperator:
comparingExpression = Expression.Equal(member, Expression.Convert(constant, member.Type));
break;
case ComparingOperators.GreaterOperator:
comparingExpression = Expression.GreaterThan(member, Expression.Convert(constant, member.Type));
break;
case ComparingOperators.GreaterThanOrEqualOperator:
comparingExpression = Expression.GreaterThanOrEqual(member, Expression.Convert(constant, member.Type));
break;
case ComparingOperators.LessOperator:
comparingExpression = Expression.LessThan(member, Expression.Convert(constant, member.Type));
break;
case ComparingOperators.LessThanOrEqualOperator:
comparingExpression = Expression.LessThanOrEqual(member, Expression.Convert(constant, member.Type));
break;
case ComparingOperators.Like:
var constantValue = Expression.Constant(value);
var stringType = typeof(string);
var method = stringType.GetMethod("Contains");
comparingExpression = Expression.Call(member, method, constant); //, member, Expression.Convert(constant, member.Type));
//comparingExpression = Expression.Call(method, member, Expression.Convert(constant, member.Type));
break;
default:
comparingExpression = Expression.Equal(member, Expression.Convert(constant, member.Type));
break;
}
//comparingExpression = Expression.Equal(member, Expression.Convert(constant, member.Type));
var lambda = Expression.Lambda <Func <T, bool> >(comparingExpression, param);
var compiledLambda = lambda.Compile();
return(compiledLambda);
}
private string BuildFailedValidationMessage <T>(ComparingOperators comparingMessage, T expected)
{
// Get ENUM description
return($"{_metricName} {comparingMessage} {expected}");
}
public static Func <T, bool> Where <T>(this Func <T, bool> predicate, string property, string value, ComparingOperators valueOperator)
{
var clause = Where <T>(property, value, valueOperator);
Func <T, bool> stat = o => clause(o) && predicate(o);
return(stat);
}
