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C# Accessing custom attribute of owner object

How can I access the custom attribute of the parent or owner object.
Look at the FieldInfo property of the SQLFieldInfo struct
Here's a more detailed program that will compile and run that shows what I need.
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
Employee myclass = new Employee();
// Load from sql server...
myclass.Name = "Alain";
myclass.Age = 51;
//----
MessageBox.Show(myclass.Name.ToString()); // Should return Alain
MessageBox.Show(myclass.Age.FieldInfo.Type.ToString()); // Should output "int"
}
}
// This next class is generated by a helper exe that reads SQL table design and create the class from it
[SQLTableAttribute(DatabaseName = "Employees", Schema = "dbo", TableName = "Employees")]
public class Employee
{
[SQLFieldAttribute(FieldName = "ID", Type = SqlDbType.Int)]
public SQLFieldInfo<int> ID { get; set; }
[SQLFieldAttribute(FieldName = "Name", Type = SqlDbType.NVarChar, Size = 200)]
public SQLFieldInfo<String> Name { get; set; }
[SQLFieldAttribute(FieldName = "Age", Type = SqlDbType.Int)]
public SQLFieldInfo<int> Age { get; set; }
}
public struct SQLFieldInfo<T>
{
private readonly T value;
public SQLFieldInfo(T Value)
{
this.value = Value;
}
public static implicit operator SQLFieldInfo<T>(T Value)
{
return new SQLFieldInfo<T>(Value);
}
public T Value
{
get
{
return this.value;
}
}
public override string ToString()
{
return this.value.ToString();
}
public SQLFieldAttribute FieldInfo
{
get
{
// Need to retreive the attribute class of the parent or declaring member
return null;
}
}
}
// Holds the sql field information
public class SQLFieldAttribute : Attribute
{
public string FieldName { get; set; }
public SqlDbType Type { get; set; }
public bool AllowNull { get; set; }
public int Size { get; set; }
}
// Holds the sql table information
public class SQLTableAttribute : Attribute
{
public string DatabaseName { get; set; }
public string Schema { get; set; } = "dbo";
public string TableName { get; set; }
}
Thank you!
Alain

My data class is as follows (should be fairly translatable to A above):
public class Foo
{
[Argument(Help = "Name", AssignmentDelimiter = "=")]
public string Name
{
get;
set;
}
}
A helper class is responsible of reading attribute values of objects:
static public string GetCommandLineDelimiter<T>(Expression<Func<T>> property)
{
if(property != null)
{
var memberExpression = (MemberExpression)property.Body;
string propertyName = memberExpression.Member.Name;
PropertyInfo prop = typeof(Arguments).GetProperty(propertyName);
if(prop != null)
{
object[] dbFieldAtts = prop.GetCustomAttributes(typeof(ArgumentAttribute), true);
if(dbFieldAtts.Length > 0)
{
return ((ArgumentAttribute)dbFieldAtts[0]).AssignmentDelimiter;
}
}
}
return null;
}
To use it, simply:
string delimiter = GetCommandLineDelimiter(() => myObject.Name);
That will get the attribute value of AssignmentDelimiter on property Name, i.e. "=".

First, MSDN is your friend.
Then, if you want to get the attributes for ancestors just specify true in the inherit flag of the method:
var attribute = typeof(A).GetProperty("myprop").GetCustomAttributes(true)
.OfType<MycustomAttrib>().FirstOrDefault();

This works. I am doing a lazy initialization of a reference to the custom attribute by using reflection to look at all the properties of all the types.
public class MycustomAttribAttribute : Attribute
{
public MycustomAttribAttribute(string name)
{
this.Name=name;
}
public string Name { get; private set; }
}
class A
{
public A() { MyProp=new B(); }
[MycustomAttrib(name: "OK")]
public B MyProp { get; set; }
}
class B
{
private static Lazy<MycustomAttribAttribute> att = new Lazy<MycustomAttribAttribute>(() =>
{
var types = System.Reflection.Assembly.GetExecutingAssembly().DefinedTypes;
foreach(var item in types)
{
foreach(var prop in item.DeclaredProperties)
{
var attr = prop.GetCustomAttributes(typeof(MycustomAttribAttribute), false);
if(attr.Length>0)
{
return attr[0] as MycustomAttribAttribute;
}
}
}
return null;
});
public string MyProp2
{
get
{
return att.Value.Name;
}
}
}
class Program
{
static void Main(string[] args)
{
// Finds the attribute reference and returns "OK"
string name = (new A()).MyProp.MyProp2;
// Uses the stored attribute reference to return "OK"
string name2 = (new A()).MyProp.MyProp2;
}
}

C# validate model by mapping values of multiple Lists

I need to run validation on JSON input model by taking the value from one List and check if it exists in another. This value is a rating is from 1 - 5. If there is no matching number, then it should throw an error. Below is the code and this logic goes in the section commented with : //check if rating exist in score table
namespace Alpha.Model
{
// INPUT
public class AlphaCalcParamMethod
{
public ICollection<PortfolioInputModel> portfolios { get; set; }
public Setting settings { get; set; }
public bool Validation(ref string errString)
{
// Check if portfolio exists
if(portfolios == null || portfolios.Count < 1)
{
errString = "At least 1 Portfolio.";
return false;
}
//check if weight adds upto 1
foreach(var portfolio in portfolios)
{
// var holdings = new List<PortfolioHoldingInput>();
var weightAggregator = 0.00;
foreach(var holding in portfolio.portfolioHoldings)
{
weightAggregator += holding.fundWeight;
}
if (weightAggregator != 1)
{
errString = "Fund Weights should add upto 1";
}
return false;
}
//check if rating exist in score table
foreach(var portfolio in portfolios)
{
var holdings = new List<PortfolioHoldingInput>();
var scores = new List<Setting>();
foreach(var holding in holdings)
{
//fetch the value of fundRating double
foreach(var score in scores)
{
//check if the value above exist in grossAlpha's List fundRating
// if it doesn't return false
}
}
return false;
}
return true;
}
}
// OUTPUT
public class AlphaCalcResultMethod
{
public List<PortfolioOutputModel> portfolios { get; set; }
}
public class PortfolioInputModel
{
public string portfolioIdentifier { get; set; }
public ICollection<PortfolioHoldingInput> portfolioHoldings { get; set; }
}
public class PortfolioOutputModel
{
public string portfolioIdentifier { get; set; }
public double portfolioAlpha { get; set; }
public ICollection<PortfolioHoldingOutput> portfolioHoldings { get; set; }
}
public class PortfolioHoldingInput
{
public string fundIdentifier { get; set; }
public int fundRating { get; set; }
public double fundExpenseRatio { get; set; }
public double fundWeight { get; set; }
}
public class PortfolioHoldingOutput
{
public string fundIdentifier { get; set; }
public int fundRating { get; set; }
public double fundExpenseRatio { get; set; }
public double fundWeight { get; set; }
public double fundAlpha { get; set; }
}
public class Setting
{
public List<GrossAlpha> grossAlphas { get; set; }
}
public class GrossAlpha
{
public int fundRating { get; set; }
public double grossAlpha { get; set; }
}
}

If you are going to return additional values from method, you should use out parameters.
Don't specify type of variable in variable name. I.e. instead of errorString just use error. Hungarian notation and other tricks are not needed with modern IDEs.
Double type is not precise. You should avoid comparing it to integer values for equality. Prefer greater or less than comparisons.
Use LINQ to replace loops
Method name Validation is a noun. That is pretty confusing for method which is action and should a verb. Consider rename it to Validate or IsValid
Code
public bool IsValid(out string error)
{
if (portfolios?.Any() == false)
{
error = "At least 1 Portfolio.";
return false;
}
if (portfolios.Any(p => p.portfolioHoldings.Sum(h => h.fundWeight) < 1))
{
error = "Fund Weights should add upto 1";
return false;
}
var holdings = portfolios.SelectMany(p => p.portfolioHoldings);
var validRatings = new List<int> { 1, 2, 3, 4, 5 };
if (holdings.Any(h => !validRatings.Contains(h.fundRating)))
{
error = "Fund ratings should be in " + String.Join(",", validRatings);
return false;
}
error = "";
return true;
}
Note: if valid ratings are sequential numbers, then you can just check range of fundRating value:
if (holdings.Any(h => h.fundRating < 1 || 5 < h.fundRating))

Look this code:
if(!score.grossAlphas.Exists(x => x.fundRating == holding.fundRating))
{
return false;
}
it check if exists grossAlphas with fundRating equals holding.fundRating.
put it in the loop where you want to check, let me know if it is what you want and if it works.

C# DynamoDB Query a nested property using LINQ

I've the MyTableItem class that maps a DynamoDB table.
I need to implements the GetMyTableItemsWithoutFinalStatus method that query the table by specific filters on nested property of a custom type, MyStatus.
The filter has to check if:
there's no status
status is not initialized
there's no "final" status in the status list
date is greater than today - daysFromNow
So my conditions in OR are:
StatusCount == 0
Status == null
Status.Where(s => s.Status != StatusEnum.DELIVERED).Count == 0
Date > DateTime.UtcNow.AddDays(-daysFromNow)
Actually I need to get back all the items that has no status or no final status, because I've to update them.
How can I implement the condition on nested property of MyStatus object?
This is my code
[Serializable]
public class MyTableItem
{
[DynamoDBHashKey]
public string Id { get; set; }
[DynamoDBProperty]
public string Field1 { get; set; }
[DynamoDBProperty]
public string Field2 { get; set; }
[DynamoDBProperty]
[DynamoDBGlobalSecondaryIndexRangeKey]
public DateTime Date { get; set; }
// My complex object
[DynamoDBProperty(typeof(MyStatusConverter))]
public MyStatus Status { get; set; }
[DynamoDBProperty]
public int StatusCount { get { return Status.Count; } set { value = Status.Count; } }
}
[Serializable]
public class MyStatus : IList<MyState>
{
private readonly IList<MyState> stateList = new List<MyState>();
public PeppolDespatchAdviceState this[int index]
{
get { return stateList[index]; }
set { stateList.Insert(index, value); }
}
public int Count
{
get { return stateList.Count; }
}
public bool IsReadOnly
{
get { return stateList.IsReadOnly; }
}
// IList interface implementation...
}
[Serializable]
public class MyState
{
public string DocumentType { get; set; }
public string Status { get; set; }
public string SkipCause { get; set; }
public DateTime Date { get; set; }
}
public enum StatusEnum
{
DEFAULT,
CREATED,
DELIVERED,
UNDELIVERABLE,
RE_RECEIVED
}
#region Converter definition
public class MyStatusConverter : IPropertyConverter
{
public DynamoDBEntry ToEntry(object value)
{
// Implementation...
}
public object FromEntry(DynamoDBEntry entry)
{
// Implementation...
}
#endregion
public IList<MyTableItem> GetMyTableItemsWithoutFinalStatus(long id, int daysFromNow = 3)
{
try
{
List<MyTableItem> items = new List<MyTableItem>();
DynamoDBOperationConfig operationConfig = new DynamoDBOperationConfig();
operationConfig.OverrideTableName = "MyTableName";
operationConfig.IndexName = "MyIndex";
List<ScanCondition> conditions = new List<ScanCondition>();
conditions.Add(new ScanCondition(MyTableItemTableAttributes.StatusCount, ScanOperator.Equal, 0));
conditions.Add(new ScanCondition(MyTableItemTableAttributes.Status, ScanOperator.IsNull));
// Here I need to add a LINQ condition: Status.Where(s => s.Status != StatusEnum.DELIVERED).Count == 0 )
conditions.Add(new ScanCondition(MyTableItemTableAttributes.Date, ScanOperator.GreaterThan, DateTime.UtcNow.AddDays(-daysFromNow)));
operationConfig.QueryFilter = conditions;
operationConfig.ConditionalOperator = ConditionalOperatorValues.Or;
DynamoDBContext context = new DynamoDBContext(DynamoDBClient);
items = context.Query<MyTableItem>(id, operationConfig).ToList();
return items;
}
catch (Exception ex)
{
throw;
}
}

How do I get the type of my ReportItems

This is a continuation of another post. I'm trying to create an interface that will let me walk through a collection of objects, and access the name of the properties of the object.
A Report object will have ReportSections. A ReportSection will have an ICollection of items which will change depending on usage.
Here's how I'm trying to define it now.
public interface IReport
{
string ReportName { get; set; }
ICollection<IReportSection> ReportSections { get; }
}
public interface IReportSection
{
string ReportSectionName { get; set; }
ICollection ReportItems { get; }
}
public abstract class ReportBase : IReport
{
virtual public string ReportType { get; set; }
virtual public string ReportName { get; set; }
virtual public ICollection<IReportSection> ReportSections { get; set; }
}
public abstract class ReportSectionBase : IReportSection
{
public string ReportSectionName { get; set; }
public ICollection ReportItems { get; set; }
}
In my code, I would do this:
public class BookAffiliates : ReportSectionBase
{
public override string ReportSectionName { get { return "Book Affiliates"; } }
public override ICollection ReportItems { get; set; }
}
public class SomeClass
{
public ICollection<AuthorsViewModel> Authors { get; set; }
public ICollection<ProjectSubmissionViewModel> Submissions { get; set; }
public string ProcessAuthorsReport()
{
var report = new ContribAuthorsReport{ ReportType = "CSV" };
var authorAffil = new BookAffiliates {ReportItems = Authors };
report.ReportSections.Add(chapAffil);
var submissionAffil = new BookAffiliates {ReportItems = Submissions};
report.ReportSections.Add(submissionAffil );
return RenderReport(report)
}
}
In RenderReport I would like to walk through the collections and use the PropertyNames:
private string RenderReport(ReportBase currentReport)
{
var reportBody = new StringBuilder();
reportBody.Append(currentReport.ReportName + Environment.NewLine + Environment.NewLine);
foreach (var thisSection in currentReport.ReportSections)
{
reportBody.Append(thisSection.ReportSectionName + Environment.NewLine);
/// ---- Here! Here! I don't know what type, I want the
/// code to get the type based on ReportSectionBase<T>
var firstItem = thisSection.ReportItems.OfType<???Type???>().FirstOrDefault();
// I would actually like to go through each property of
// the ReportItem type and list it here.
foreach(var prop in firstItem.GetType().GetProperties())
{
reportBody.AppendLine(string.Format("{0}:{1}" prop.Name, prop.Value));
}
}
return reportBody.ToString();
}
I'm not sure how to best define this. I'm pretty sure I've done it before, but it's not coming to me.

You would use Reflection to do it.
foreach(var prop in thisItem.GetType().GetProperties())
{
reportBody.AppendLine(string.Format("{0}:{1}" prop.Name, prop.Value));
}

Took a while, a lot of questions, and figuring out what I really wanted to ask. I came up with this.
Here are my interfaces and base classes:
public class ReportBase
{
public ReportBase()
{
ReportSections = new List<IReportSection>();
}
public string ReportType { get; set; }
public string ReportName { get; set; }
public ICollection<IReportSection> ReportSections { get; set; }
}
public interface IReportSection
{
string ReportSectionName { get; }
ICollection ReportItems { get; set; }
}
public class ReportSection<T> : IReportSection
{
public string ReportSectionName { get; set; }
public ICollection<T> ReportItems { get; set; }
ICollection IReportSection.ReportItems
{
get { return ReportItems as ICollection; }
set { ReportItems = value as ICollection<T>; }
}
}
I create my objects like this:
public ReportBase GetContribAuthorsReport
(
ICollection<ProjectAffiliateViewModel> projectAffiliates,
ICollection<SubmissionAffiliateViewModel> submissionAffiliates
)
{
//var caReport = new ContributingAffiliates("CSV", projectAffiliates, submissionAffiliates);
var caReport = new ReportBase { ReportType = "CSV", ReportName = "Reviewers' Contact Information" };
caReport.ReportSections.Add(new ReportSection<ProjectAffiliateViewModel> { ReportItems = projectAffiliates });
caReport.ReportSections.Add(new ReportSection<SubmissionAffiliateViewModel> { ReportItems = submissionAffiliates });
return caReport;//.Report;
}
Then I iterate through the objects like this:
public class DownloadCsvActionResult : ActionResult
{
public ReportBase Report { get; set; }
public string fileName { get; set; }
private string ReportData { get; set; }
public DownloadCsvActionResult(ReportBase report, string pFileName)
{
Report = report;
fileName = pFileName;
ReportData = RenderReport();
}
private string RenderReport()
{
var reportBody = new StringBuilder();
reportBody.AppendLine(Report.ReportName);
reportBody.Append(Environment.NewLine + Environment.NewLine);
foreach (var thisSection in Report.ReportSections)
{
reportBody.Append(thisSection.ReportSectionName + Environment.NewLine);
if (thisSection.ReportItems != null)
{
var itemType = thisSection.ReportItems.GetType().GetGenericArguments().Single();
var first = true;
foreach (var prop in itemType.GetProperties())
{
if (!first) reportBody.Append(",");
DisplayAttribute attribute = prop.GetCustomAttributes(typeof(DisplayAttribute), false)
.Cast<DisplayAttribute>()
.SingleOrDefault();
string displayName = (attribute != null) ? attribute.Name : prop.Name;
reportBody.Append(displayName);
first = false;
}
reportBody.Append(Environment.NewLine);
foreach (var thisItem in thisSection.ReportItems)
{
var firstData = true;
foreach (var prop in itemType.GetProperties())
{
if (!firstData) reportBody.Append(",");
reportBody.Append(prop.GetValue(thisItem,null));
firstData = false;
}
reportBody.Append(Environment.NewLine);
}
}
reportBody.Append(Environment.NewLine);
}
return reportBody.ToString();
}
public override void ExecuteResult(ControllerContext context)
{
//Create a response stream to create and write the Excel file
HttpContext curContext = HttpContext.Current;
curContext.Response.Clear();
curContext.Response.AddHeader("content-disposition", "attachment;filename=" + fileName);
curContext.Response.Charset = "";
curContext.Response.Cache.SetCacheability(HttpCacheability.NoCache);
curContext.Response.ContentType = "application/vnd.ms-excel";
//Write the stream back to the response
curContext.Response.Write(ReportData);
curContext.Response.End();
}
}
This gives me what I need for now. Sorry I wasn't as clear in the first place, and thank you for all your help.

How to set a property of a generic object in a list?

My class structure looks like this:
public interface IStationProperty
{
int Id { get; set; }
string Desc { get; set; }
object Value { get; }
Type ValueType { get; }
}
[Serializable]
public class StationProp<T> : IStationProperty
{
public StationProp()
{
}
public StationProp(int id, T val, string desc = "")
{
Id = id;
Desc = desc;
Value = val;
}
public int Id { get; set; }
public string Desc { get; set; }
public T Value { get; set; }
object IStationProperty.Value
{
get { return Value; }
}
public Type ValueType
{
get { return typeof(T); }
}
}
Which allows me to add multiple generic types to the same list like this:
var props = new List<IStationProperty>();
props.Add(new StationProp<int>(50, -1, "Blah"));
props.Add(new StationProp<bool>(53, true, "Blah"));
props.Add(new StationProp<int>(54, 10, "Blah"));
What I would like to do now is be able to change just the value of an item in this list, without changing the Type.
Is this possible?

I assume that you know an index of the item you want to change and you know what type it is. Then it goes like the following
(props[0] as StationProp<int>).Value = 5;
If you are not sure of its type
var item = props[i] as StationProp<int>;
if (item != null)
{
item.Value = 5;
}
Does this answer your question? I'm not much sure what else would you like to achieve.