/// <summary>
///
/// </summary>
/// <param name="dataIndices"></param>
/// <returns></returns>
public Expression <Func <T, object> > GetExpression(IDictionary <int, string> dataIndices)
{
// Get type of root object
Type type = typeof(T);
ParameterExpression parentParameterExpression = Expression.Parameter(type, "x");
MemberExpression memberExpression = default(MemberExpression);
// Loop through each node
IOrderedEnumerable <KeyValuePair <int, string> > orderedList = dataIndices.OrderBy(x => x.Key);
for (int i = 0; i < dataIndices.Count; i++)
{
// Get the current record in the loop
string dataIndex = orderedList.ElementAt(i).Value;
// If this is the first iteration, just set the variable - else append the expa
memberExpression = i == 0
? Expression.PropertyOrField(parentParameterExpression, dataIndex)
: Expression.PropertyOrField(memberExpression, dataIndex);
// Check if the last field corresponds to a complex type or a standard type (struct)
if (i != dataIndices.Count - 1)
{
continue;
}
// Use some reflection to capture the class' and properties metadata
PropertyInfo propertyInfo = (PropertyInfo)memberExpression.Member;
bool isReferenceType = propertyInfo != null &&
!propertyInfo.PropertyType.GetTypeInfo().IsValueType &&
!propertyInfo.PropertyType.GetTypeInfo().IsPrimitive &&
propertyInfo.PropertyType != typeof(string);
if (!isReferenceType)
{
continue;
}
DefaultDisplayAttribute classDefaultDisplayAttribute =
propertyInfo
.PropertyType
.GetTypeInfo()
.GetCustomAttribute <DefaultDisplayAttribute>();
if (classDefaultDisplayAttribute != null)
{
memberExpression = Expression.PropertyOrField(memberExpression, classDefaultDisplayAttribute.Name);
}
}
UnaryExpression sortExpression = Expression.Convert(memberExpression, typeof(object));
return(Expression.Lambda <Func <T, dynamic> >(sortExpression, parentParameterExpression));
}
/// <summary>
/// Inspects the property type and overrides the property field by the value specified in the default display attribute.
/// </summary>
/// <param name="memberField">The member field to inspect</param>
/// <returns>The member expression</returns>
internal static MemberExpression OverrideWithDefaultDisplay(this MemberExpression memberField)
{
// Check the type of the property
PropertyInfo propertyInfo = memberField.Member as PropertyInfo;
bool isPropertyReferenceType = propertyInfo != null &&
propertyInfo.PropertyType != typeof(string) &&
!propertyInfo.PropertyType.GetTypeInfo().IsValueType &&
!propertyInfo.PropertyType.GetTypeInfo().IsPrimitive;
if (!isPropertyReferenceType)
{
return(memberField);
}
DefaultDisplayAttribute classDefaultDisplayAttribute = propertyInfo
.PropertyType
.GetTypeInfo()
.GetCustomAttribute <DefaultDisplayAttribute>();
return(classDefaultDisplayAttribute != null
? Expression.PropertyOrField(memberField, classDefaultDisplayAttribute.Name)
: null);
}
