I can't find a solution to my problem, so I try ask here. I have a class and I want to have a method in the class to test for the state of the Properties. The method should return true if any of the properties has more one or more values assigned. But i cannot find any examples of how to loop trough all the properties of the class itself with reflection and test if Count is > than 0.
Or should I use another technique than reflection?
I just want to avoid hard coding the Properties one more time in the Test method.
using System.Reflection;
public class cP
{
public Guid gid { get; set; } = Guid.NewGuid();
public List<string> p1 { get; set; } = new List<string>();
public List<string> p2 { get; set; } = new List<string>();
public bool HasDefinedValues()
{
List<PropertyInfo> properties = this.GetType().GetProperties().ToList();
foreach (PropertyInfo property in properties)
{
if (property.PropertyType == typeof(List<int>))
{
string PName = property.Name;
if (((List<int>)property.GetValue(property.Name, null)).Count > 0) { return true; };
}
}
return false;
}
}
This is working now 😃
using System.Reflection;
public class cP
{
public Guid gid { get; set; } = Guid.NewGuid();
public List<string> p1 { get; set; } = new List<string>();
public List<string> p2 { get; set; } = new List<string>();
public bool HasDefinedValues()
{
List<PropertyInfo> properties = this.GetType().GetProperties().ToList();
foreach (PropertyInfo property in properties)
{
if (property.PropertyType == typeof(List<string>))
{
if (((List<string>)property.GetValue(this, null)).Count > 0) { return true; };
}
}
return false;
}
}
Related
I have to an upper class with nested classes
public class Preferences
{
public FunctionClass function { get; set; } = new FunctionClass();
public class FunctionClass
{
public string programfolder { get; set; } = "";
...
}
public LoggerClass logger { get; set; } = new LoggerClass();
public class LoggerClass
{
public string logFolder { get; set; } = "Log";
...
}
public OptionClass options { get; set; } = new OptionClass();
public class OptionClass
{
public bool showGraphics { get; set; } = true;
...
}
public MqttSpSetupClass MqttSpSetup { get; set; } = new MqttSpSetupClass();
public class MqttSpSetupClass
{
public string strAddress { get; set; } = "localhost";
...
}
}
so I want reflection to cycle on all member of each inner class
PropertyInfo[] props_Outer = typeof(IoAppPreferences).GetProperties();
int counter = 0;
foreach (PropertyInfo prop_Upper in props_Outer)
{
var sName_Outer = prop_Upper.Name;
var val_Outer = props_Outer.GetValue(counter ++);
PropertyInfo[] properties_Inner;
switch (sName_Outer.ToUpper())
{
case "DIMS": properties_Inner = typeof(IoAppPreferences.DimsClass).GetProperties(); break;
...
}
foreach (PropertyInfo prop_Inner in properties_Inner)
{
var sName = prop_Inner.Name;
//prefs.function
var sVal = prop_Inner.GetValue(val_Outer);<------ERROR
switch (prop_Inner.Name.ToUpper())
{
...
}
}
I get an error where I put the arrow. And the reason is that val_Outer is FunctionClass function while if I hardcode prefs.function it is ok. Of course, I can put a switch per each one, but my question is: is there a better way to solve it?
I have seen this solution but can't fit to my needs
You got error because val_Outer is wrong instance. You are trying to get value out of counter integer props_Outer.GetValue(counter ++)
If your goal is to get property values from nested classes you must have instance of Preferences object:
var appPreferences = new Preferences();
var propsOuter = appPreferences.GetType().GetProperties();
foreach (var po in propsOuter)
{
var valueOuter = po.GetValue(appPreferences);
Console.WriteLine($"{po.Name}");
if (valueOuter == null) continue;
var propsInner = valueOuter.GetType().GetProperties();
foreach (var pi in propsInner)
{
var valueInner = pi.GetValue(valueOuter);
Console.WriteLine($"{pi.Name}: {valueInner}");
}
}
But getting values through reflection is pretty much useless if you already have object instance.
I have three models as describe below:
public class ComponentData //Contains list of Component Model
{
public int id { get; set; }
public List<Component> Components { get; set; }
}
public class Component //Contains list of ComponentValue Model
{
public Int32 SiteId { get; set; }
public IList<ComponentValue> ComponentValues { get; set; }
}
public class ComponentValue //Contains list of it self i.e. ComponentValue Model
{
public String Id { get; set; }
public String Name { get; set; }
public String DisplayName { get; set; }
public IList<ComponentValue> ChildComponents { get; set; }
}
Now I have two objects old ComponentData and new ComponentData, I want to compare these two object and want to find whether new list has any new child added or any changes in existing child. How to do that?
Note : public IList<ComponentValue> ChildComponents { get; set; } can have multiple children in it recursively.
I tried:
using (var e1 = cdOld.Components.GetEnumerator())
using (var e2 = cdNew.Components.GetEnumerator())
{
while (e1.MoveNext() && e2.MoveNext())
{
var item1 = e1.Current.ComponentValues;
var item2 = e2.Current.ComponentValues;
using (var i1 = item1.GetEnumerator())
using (var i2 = item2.GetEnumerator())
{
while (i1.MoveNext() && i2.MoveNext())
{
//Here not sure how many children both list has and how to make recursive call
var item11 = i1.Current;
var item12 = i2.Current;
if (item11.Id != item12.Id || item11.Name != item12.Name)
{
cvlistold.Add(item11);
cvlistnew.Add(item12);
}
}
}
//var firstNotSecond = item1.Except(item2).ToList();
//var secondNotFirst = item2.Except(item1).ToList();
//var v = item1.Select(a => a.Name).Intersect(item2.Select(b => b.Name)).ToList();
//bool c = !(!firstNotSecond.Any() && !secondNotFirst.Any());
}
}
Screenshot:
Use IEquatable interface (or override Equals and GetHashCode):
public class ComponentValue : IEquatable<ComponentValue>
{
public String Id { get; set; }
public String Name { get; set; }
public String DisplayName { get; set; }
public IList<ComponentValue> ChildComponents { get; set; }
public bool Equals(ComponentValue other)
{
return Id == other.Id && Name == other.Name;
}
}
Then, check the differences:
bool equals = e1.SequenceEqual(e2);
I had similar structure in one of my projects with the difference that they could've contain more element types then one so I've made some reflection code to look up and compare these :
public static bool Compare ( this T obj, T comparer )
{
bool isOkay = true;
foreach(var field in typeof(T).GetFields(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
{
if (!isOkay) break;
object value = field.GetValue(obj);
object comparerValue = field.GetValue(comparer);
Type type = field.FieldType;
if(Type.GetTypeCode(type) != TypeCode.Object)
{
if(type == typeof(IList))
{
for(int i = 0; i < ((IList)value).Count; i++)
{
isOkay = isOkay &&(bool)_GenericCompare.MakeGenericMethod(((IList)value)[i].GetType()).Invoke(((IList)value)[i], ((IList)comparerValue)[i]);
}
}
}
else
{
isOkay = isOkay && value.Equals(comparerValue);
}
}
return isOkay;
}
// _GenericVompare is :
typeof(MeTypeThatHasCompareMethod).GetMethod("Compare", BindingFlags.Static | BindingFlags.Public);
This is just a shortened method which I've done so you should modify this for your needs but basically it iterates through all items of IList typed field and Invokes the same method on that items.
FYI. This method can be slow as hell on huge lists so you should implement some kind of "cache" mechanism to store FieldInfo[] for some types and _GenericCompare MethodInfo to speed up the process.
I have a list where TestClass is a class with some predefined properties. So when i get data and bind my list with data i need to ignore some properties of TestClass by comparing it with a list. How can i achieve that?
Below is my code
public class TestClass
{
public int id{get;set;}
public string fname{get;set;}
public string lname{get;set;}
public string job {get;set;}
public string role{get;set;}
public string address{get;set;}
}
List<TestClass> ulist = null;
ulist = ToList<TestClass>(usersdataset.tables[0]); //fill my list with the data code is given below
so after getting the data into the list i need to remove some properties by comparing it with list of properties which should be returned.for example if my filteredlist should only show id,fname,role then i need to remove the extra properties from my ulist. so after the filter ulist should only contain id,fname and role
ToList Method
public static List<T> ToList<T>(DataTable dataTable) where T : new()
{
var dataList = new List<T>();
//Define what attributes to be read from the class
const BindingFlags flags = BindingFlags.Public | BindingFlags.Instance;
//Read Attribute Names and Types
var objFieldNames = typeof(T).GetProperties(flags).Cast<PropertyInfo>().
Select(item => new
{
Name = item.Name,
Type = Nullable.GetUnderlyingType(item.PropertyType) ?? item.PropertyType
}).ToList();
//Read Datatable column names and types
var dtlFieldNames = dataTable.Columns.Cast<DataColumn>().
Select(item => new {
Name = item.ColumnName,
Type = item.DataType
}).ToList();
foreach (DataRow dataRow in dataTable.AsEnumerable().ToList())
{
var classObj = new T();
foreach (var dtField in dtlFieldNames)
{
PropertyInfo propertyInfos = classObj.GetType().GetProperty(dtField.Name);
var field = objFieldNames.Find(x => x.Name == dtField.Name);
//var field = filteredColumns.Find(x => x.PropertyName == dtField.Name);
if (field != null)
{
if (dataRow[dtField.Name] != DBNull.Value)
propertyInfos.SetValue(classObj, dataRow[dtField.Name], null);
}
}
dataList.Add(classObj);
}
return dataList;
}
Use the overvride function Equals:
This sample compare only the id property
public class TestClass
{
public int id { get; set; }
public string fname { get; set; }
public string lname { get; set; }
public string job { get; set; }
public string role { get; set; }
public string address { get; set; }
public override bool Equals(object obj)
{
if (obj.GetType().Name != this.GetType().Name)
{
return false;
}
TestClass testclassObject = (TestClass)obj;
if (testclassObject.id != this.id)
{
return false;
}
return true;
}
I am standing on a complex issue for me. I need update some models, but I like to work with a generic class not to rewrite some code individually.
I need to update data that have lists on their properties, with possible exclusion or inclusion of items on these lists, but these lists can be of any other class / type. My questions are commented on the code.
These models are unrealistic and a bit absurds but have similarities with my real models, note that the logic is reversed on these relationships during updates.
Thanks for all.
public class RedNotebook
{
[Key]
public int Id { get; set; }
public string PageTitle { get; set; }
public virtual ICollection<Signature> Signatures { get; set; }
}
public class BlueNotebook
{
[Key]
public int Id { get; set; }
public DateTime Entrance { get; set; }
public DateTime Leave { get; set; }
public virtual ICollection<Guest> GuestList { get; set; }
}
public class Signature
{
[key]
public int Id { get; set; }
public string PeopleSignature { get; set; }
public int IdRedNotebook { get; set; }
public int IdBlueNotebook { get; set; }
[ForeignKey("IdRedNotebook")]
public virtual RedNotebook { get; set; }
[ForeignKey("IdBlueNotebook")]
public virtual BlueNotebook { get; set; }
}
public class Guest
{
[key]
public int Id { get; set; }
public string Name { get; set; }
public int SeatNumber { get; set; }
public int IdBlueNotebook { get; set; }
[ForeignKey("IdBlueNotebook")]
public virtual BlueNotebook { get; set; }
}
/**********************/
public void UpdateData(T newData, out string msg)
{
try
{
var propId = newData.GetType().GetProperty("Id");
if (propId == null)
{
msg = "Unable to identify the identity of the reported data.";
return;
}
int id = Convert.ToInt32(propId.GetValue(newData));
if (id <= 0)
{
msg = "Unable to identify the identity of the reported data.";
return;
}
//instance a determined DbContext and Model<T>
var contexto = new CtxCliente(DAO.Classes.Util.InstanciarConexao(strCripto, (DAO.Conectores) Conector));
var model = contexto.Set<T>();
var targetData = model.Find(id);
if (targetData == null)
{
model.Add(newData);
contexto.Entry(model).State = EntityState.Added;
msg = "An addition was made because there was no previous reference.";
}
if (Convert.ToInt32(targetData.GetType().GetProperty("Id").GetValue(targetData)) > 0)
{
contexto.Entry(targetData).CurrentValues.SetValues(newData);
contexto.Entry(targetData).State = EntityState.Modified;
msg = string.Empty;
}
//TODO - 1) GET THE VIRTUAL PROPERTIES OF WHICH TYPE targetData ICollection
//TODO - 2) COMPARE THE CONTENT OF VIRTUAL PROPERTIES OF targetData WITH THE CONTENTS OF VIRTUAL PROPERTIES UPDATE, BOTH ICollection
//TODO - 3) REMOVE EXCESS OF targetData AND / OR ADD THAT AS THE CASE MAY BE MISSING (A - CLEAR DIFFERENCE, B - ADD DIFFERENCE)
//through the properties to identify those that are of the collection type
foreach (var propertytargetData in targetData.GetType().GetProperties())
{
if (!propertytargetData.PropertyType.IsGenericType)
continue;
var propsNewData = newData.GetType().GetProperty(propertytargetData.Name);
#region
//if all list items were removed on update
if (propsNewData == null && propertytargetData != null)
{
// NOT TESTED, MAYBE NOT WORK CORRECTLY
propertytargetData.SetValue(targetData,null);
}
//If an item was included or removed
else if (propsNewData != null)
{
var valTargetData = propertytargetData.GetValue(targetData);
var valNewData = propsNewData.GetValue(newData);
var listItemsTargetData = (IEnumerable) valTargetData;
var listItemsNewData = (IEnumerable) valNewData;
int countItemsTargetData = listItemsTargetData.Cast<object>().Count();
int countItemsNewData = listItemsNewData.Cast<object>().Count();
if (countItemsTargetData > countItemsNewData) //remove discarded
{
foreach (var itemtargetData in listItemsTargetData)
{
var idItemtargetData = itemtargetData.GetType().GetProperty("Id").GetValue(itemtargetData);
var existing = (from object itemListNewData in listItemsNewData
select itemListNewData.GetType().GetProperty("Id").GetValue(itemListNewData))
.Any(iditemListNewData => (int) idItemtargetData == (int) iditemListNewData);
if (!existing) //remove
{
//how to remove from the list?????? (targetData)
}
else //update
{
foreach (var itemListNewData in listItemsNewData)
{
var props = itemListNewData.GetType().GetProperties();
foreach (var propertyInfo in props)
{
foreach (var item in listItemsTargetData)
{
var p = item.GetType().GetProperty(propertyInfo.Name);
if (p != null && !p.PropertyType.IsGenericType)
{
p.SetValue(item, propertyInfo.GetValue(itemListNewData));
}
}
}
}
}
}
}
else if (countItemsTargetData < countItemsNewData) //Items need to be included
{
foreach (var newItem in listItemsNewData)
{
var idnewItem = newItem.GetType().GetProperty("Id").GetValue(newItem);
if ((int) idnewItem == 0)
{
//how to insert in list???????? (targetData)
}
else // remove and/or update some before (reduntant!?)
{
foreach (var itemtargetData in listItemsTargetData)
{
var idItemtargetData = itemtargetData.GetType().GetProperty("Id").GetValue(itemtargetData);
var existing = (from object itemListNewData in listItemsNewData
select itemListNewData.GetType().GetProperty("Id").GetValue(itemListNewData))
.Any(iditemListNewData => (int)idItemtargetData == (int)iditemListNewData);
if (!existing) //remove
{
//how to remove from the list?????? (targetData)
}
else //update
{
foreach (var itemListNewData in listItemsNewData)
{
var props = itemListNewData.GetType().GetProperties();
foreach (var propertyInfo in props)
{
foreach (var item in listItemsTargetData)
{
var p = item.GetType().GetProperty(propertyInfo.Name);
if (p != null && !p.PropertyType.IsGenericType)
{
p.SetValue(item, propertyInfo.GetValue(itemListNewData));
}
}
}
}
}
}
}
}
}
}
}
contexto.SaveChanges(); //save data on model
}
catch(...){}
}
Haven't tested it . But it should work if both source and dest implement the same ICollection interface and T has an Id property of type System.Int32. It uses the new dynamic keyword that enables you to do duck typing ;
private class IdComparer : IEqualityComparer<object>
{
public bool Equals(object x, object y)
{
//return ((dynamic) x).Id = ((dynamic) y).Id; //previous with convertion error
return ((dynamic) x).Id == ((dynamic) y).Id;
}
public int GetHashCode(object obj)
{
return ((dynamic) obj).Id;
}
}
private static void Copy(IEnumerable source, IEnumerable dest)
{
var cmp = new IdComparer();
var toRemove = dest.Cast<object>().Except(source.Cast<object>(),cmp).ToList();
var toAdd= source.Cast<object>().Except(dest.Cast<object>(),cmp).ToList();
foreach(var item in toAdd)
{
// dynamic runtime tries to find method that matches signiture void Add(T value so we add dummy variable so that it knows to search for bool Add(T value)
var dummy= ((dynamic) dest).Add(item);
}
foreach (var item in toRemove)
{
var dummy= ((dynamic)dest).Remove(item);
}
}
,I have one class in which I have three properties now what I want to do, if in the object if any one of null or empty then I want to remove it from the object below is my code.
public class TestClass
{
public string Name { get; set; }
public int ID { get; set; }
public DateTime? DateTime { get; set; }
public string Address { get; set; }
}
TestClass t=new TestClass();
t.Address="address";
t.ID=132;
t.Name=string.Empty;
t.DateTime=null;
Now here I want the object of TestClass but in that Name and DateTime property should not be their in the object,
is it possible?
Please help me
There's no such concept as removing a property from an individual object. The type decided which properties are present - not individual objects.
In particular, it will always be valid to have a method like this:
public void ShowDateTime(TestClass t)
{
Console.WriteLine(t.DateTme);
}
That code has no way of knowing whether you've wanted to "remove" the DateTime property from the object that t refers to. If the value is null, it will just get that value - that's fine. But you can't remove the property itself.
If you're listing the properties of an object somewhere, you should do the filtering there, instead.
EDIT: Okay, no you've given us some context:
ok I am using Schemaless database so null and empty value also store space in database that's the reason
So in the code you're using which populates that database, just don't set any fields which corresponds to properties with a null value. That's purely a database population concern - not a matter for the object itself.
(I'd also argue that you should consider how much space you'll really save by doing this. Do you really care that much?)
I was bored and got this in LINQPad
void Main()
{
TestClass t=new TestClass();
t.Address="address";
t.ID=132;
t.Name=string.Empty;
t.DateTime=null;
t.Dump();
var ret = t.FixMeUp();
((object)ret).Dump();
}
public static class ReClasser
{
public static dynamic FixMeUp<T>(this T fixMe)
{
var t = fixMe.GetType();
var returnClass = new ExpandoObject() as IDictionary<string, object>;
foreach(var pr in t.GetProperties())
{
var val = pr.GetValue(fixMe);
if(val is string && string.IsNullOrWhiteSpace(val.ToString()))
{
}
else if(val == null)
{
}
else
{
returnClass.Add(pr.Name, val);
}
}
return returnClass;
}
}
public class TestClass
{
public string Name { get; set; }
public int ID { get; set; }
public DateTime? DateTime { get; set; }
public string Address { get; set; }
}
Hereby a 'slightly' more clear and shorter version of the accepted answer.
/// <returns>A dynamic object with only the filled properties of an object</returns>
public static object ConvertToObjectWithoutPropertiesWithNullValues<T>(this T objectToTransform)
{
var type = objectToTransform.GetType();
var returnClass = new ExpandoObject() as IDictionary<string, object>;
foreach (var propertyInfo in type.GetProperties())
{
var value = propertyInfo.GetValue(objectToTransform);
var valueIsNotAString = !(value is string && !string.IsNullOrWhiteSpace(value.ToString()));
if (valueIsNotAString && value != null)
{
returnClass.Add(propertyInfo.Name, value);
}
}
return returnClass;
}
You could take advantage of the dynamic type:
class Program
{
static void Main(string[] args)
{
List<dynamic> list = new List<dynamic>();
dynamic
t1 = new ExpandoObject(),
t2 = new ExpandoObject();
t1.Address = "address1";
t1.ID = 132;
t2.Address = "address2";
t2.ID = 133;
t2.Name = "someName";
t2.DateTime = DateTime.Now;
list.AddRange(new[] { t1, t2 });
// later in your code
list.Select((obj, index) =>
new { index, obj }).ToList().ForEach(item =>
{
Console.WriteLine("Object #{0}", item.index);
((IDictionary<string, object>)item.obj).ToList()
.ForEach(i =>
{
Console.WriteLine("Property: {0} Value: {1}",
i.Key, i.Value);
});
Console.WriteLine();
});
// or maybe generate JSON
var s = JsonSerializer.Create();
var sb=new StringBuilder();
var w=new StringWriter(sb);
var items = list.Select(item =>
{
sb.Clear();
s.Serialize(w, item);
return sb.ToString();
});
items.ToList().ForEach(json =>
{
Console.WriteLine(json);
});
}
}
May be interfaces will be handy:
public interface IAdressAndId
{
int ID { get; set; }
string Address { get; set; }
}
public interface INameAndDate
{
string Name { get; set; }
DateTime? DateTime { get; set; }
}
public class TestClass : IAdressAndId, INameAndDate
{
public string Name { get; set; }
public int ID { get; set; }
public DateTime? DateTime { get; set; }
public string Address { get; set; }
}
Creating object:
IAdressAndId t = new TestClass()
{
Address = "address",
ID = 132,
Name = string.Empty,
DateTime = null
};
Also u can put your interfaces in separate namespace and make your class declaration as internal. After that create some public factories which will create the instances of your classes.