/// <summary>
/// Apply ordering to sort queryable result.
/// </summary>
/// <typeparam name="T">Type of queryable objects.</typeparam>
/// <param name="query">Query.</param>
/// <param name="propertyName">Name of property.</param>
/// <param name="method">Flag of order method.</param>
/// <returns>
/// Ordered queryable object (IOrderedQueryable).
/// </returns>
/// <remarks>
/// Use reflection (not ComponentModel) to mirror LINQ.
/// </remarks>
private static IOrderedQueryable <T> Order <T>(IQueryable <T> query, string propertyName, EOrderMethod method)
{
Ensure.NotNull(query, nameof(query));
Ensure.NotEmpty(propertyName, nameof(propertyName));
string[] propertyNameParts = propertyName.Split('.');
Type type = typeof(T);
ParameterExpression arg = Expression.Parameter(type, "x");
Expression expression = arg;
foreach (string propertyNamePart in propertyNameParts)
{
PropertyInfo propertyInfo = type.GetProperty(propertyNamePart, BindingFlags.IgnoreCase | BindingFlags.Public | BindingFlags.Instance);
if (propertyInfo == null)
{
throw new InvalidOperationException($"Nested property with name {propertyName} for type {typeof(T).Name} was not found.");
}
expression = Expression.Property(expression, propertyInfo);
type = propertyInfo.PropertyType;
}
Type delegateType = typeof(Func <,>).MakeGenericType(typeof(T), type);
LambdaExpression lambda = Expression.Lambda(delegateType, expression, arg);
object result = typeof(Queryable).GetMethods().Single(
m => m.Name == method.ToString() &&
m.IsGenericMethodDefinition &&
m.GetGenericArguments().Length == 2 &&
m.GetParameters().Length == 2)
.MakeGenericMethod(typeof(T), type)
.Invoke(null, new object[] { query, lambda });
return((IOrderedQueryable <T>)result);
}
private static IOrderedEnumerable <T> Order <T>(IEnumerable <T> source, string propertyName, EOrderMethod method)
{
Ensure.NotNull(source, nameof(source));
Ensure.NotEmpty(propertyName, nameof(propertyName));
string[] propertyNameParts = propertyName.Split('.');
Type type = typeof(T);
ParameterExpression arg = Expression.Parameter(type, "x");
Expression expr = arg;
foreach (string propertyNamePart in propertyNameParts)
{
// Use reflection (not ComponentModel) to mirror LINQ
PropertyInfo propertyInfo = type.GetProperty(propertyNamePart);
if (propertyInfo == null)
{
throw new InvalidOperationException($"Nested property with name {propertyName} for type {typeof(T).Name} was not found.");
}
expr = Expression.Property(expr, propertyInfo);
type = propertyInfo.PropertyType;
}
Type delegateType = typeof(Func <,>).MakeGenericType(typeof(T), type);
LambdaExpression lambda = Expression.Lambda(delegateType, expr, arg);
object result = typeof(Enumerable).GetMethods().Single(
m => m.Name == method.ToString() &&
m.IsGenericMethodDefinition &&
m.GetGenericArguments().Length == 2 &&
m.GetParameters().Length == 2)
.MakeGenericMethod(typeof(T), type)
.Invoke(null, new object[] { source, lambda.Compile() });
return((IOrderedEnumerable <T>)result);
}
