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How to call a Generic method with dynamic properties in C#

I have the a few methods that have similar signature and was trying to convert them into one generic one without the use of interfaces.
public List<MultiSelectDropdown> ConvertListOfJobStatusToDropdownListClickable(List<JobStatus> js) {
var list = new List<MultiSelectDropdown>();
if (js != null && js.Count >= 1) {
list = js.Select(item => new MultiSelectDropdown { Name = item.StatusValue, Value = item.id.ToString() }).ToList();
}
return list;
}
public List<MultiSelectDropdown> ConvertListOfCUsersToDropdownListClickable(List<cUser> users) {
var list = new List<MultiSelectDropdown>();
if (users != null && users.Count >= 1) {
list = users.Select(item => new MultiSelectDropdown { Name = item.User_Name, Value = item.Id.ToString() }).ToList();
}
return list;
}
This is what I would like to do; pass in a list with two properties.
List<MultiSelectDropdown> ddlForClientUsers = ConvertToMultiSelectDropdownList(listOfClientsForUser, n => n.Client_Id, v => v.Client);
List<MultiSelectDropdown> ddlForJobStatus = ConvertToMultiSelectDropdownList(listOfJobStatus, n => n.Id, v => v.JobName);
This is the method I have tried but not sure how to get item.propName and item.propValue to work.
I get "Cannot resolve" propName and propValue in the method below
Is this possible?
public List<MultiSelectDropdown> ConvertToMultiSelectDropdownList<T, TPropertyName, TPropertyValue>(List<T> listOfT, Func<T, TPropertyName> propName, Func<T, TPropertyValue> propValue) {
var list = new List<MultiSelectDropdown>();
if (listOfT != null && listOfT.Count >= 1) {
list = listOfT.Select(item => new MultiSelectDropdown { Name = item.propName, Value = item.propValue }).ToList();
}
return list;
}
public class MultiSelectDropdown {
public string Name { get; set; }
public string Value { get; set; }
public bool IsChecked { get; set; }
}

Because the properties of your MultiSelectDropdown are strings, your functions should return those as well. And to invoke the functions, you have to write them like propName(item) instead of item.propName - that is the property syntax, and you indicated you didn't want to use interfaces.
public List<MultiSelectDropdown> ConvertToMultiSelectDropdownList<T>(List<T> listOfT, Func<T, string> propName, Func<T, string> propValue) {
var list = new List<MultiSelectDropdown>();
if (listOfT != null && listOfT.Count >= 1) {
list = listOfT.Select(item => new MultiSelectDropdown { Name = propName(item), Value = propValue(item) }).ToList();
}
return list;
}

You are really close, with just a slight mistake. The line (reformatted to prevent scrolling):
list = listOfT.Select(item => new MultiSelectDropdown
{
Name = item.propName,
Value = item.propValue
}).ToList();
needs to be:
list = listOfT.Select(item => new MultiSelectDropdown
{
Name = propName(item),
Value = propValue(item)
}).ToList();

How to compare all values in an object without repeating if statements?

I am trying to compare all possible values in a list of objects like this:
public class Object21
{
int Id,
bool firstbool,
bool secondbool
}
I would loop through the objects and compare them like this:
List<Object1> objects;
foreach(var o in objects)
{
if(firstbool && secondbool)
....
if(firstbool && !secondbool)
....
if(!firstbool && secondbool)
....
if(!firstbool && !secondbool)
....
}
This seems ok, but what if the object had several values that you were running through if statements.
public class Object2
{
int Id;
int firstbool;
....
int twentiethbool;
}
Then you would have to write out all of the possible conditional statements and your code would be terribly written and hard to read.
List<Object2> objects2;
foreach(var o in objects2)
{
if(firstbool && secondbool && ... && twentiethbool)
....
if(....)
....
....
....
if(!firstbool && !secondbool && ... && !twentiethbool)
....
}
Is there a simpler way to write the second scenario so that you are not writing every combination of if statements?
In the end I would like to calculate the percentage occurrence of each condition in the list.

To answer the first part of the question (about comparing every combination):
There isn't really a good way to do that, other than write a bunch of if statements. Of course; you probably shouldn't be doing that anyways :)
You could probably use reflection and recursion, but thats going to get messy really fast.
Luckily, to just get the percentage occurrence of each flag, you can just do:
list.Count(i => i.firstbool) / (double)list.Count();
...

first, create a dictionary to save all conditions
var dict = new Dictionary<string, int>{{"001",0},{"010",0} ...}
then, create key use bool values
var key=string.Empty;
key+=firstbool ?"0":"1"
key+=secondbool ?"0":"1"
......
after all, you can know which condition occurred
dict[key]++;

Given a class structure like this:
public class YourClass
{
public int Id { get; set; }
public bool firstbool { get; set; }
public bool secondbool { get; set; }
public bool thirdbool { get; set; }
}
You can use reflection to get all the boolean values (and only bool values) inside the class:
public IEnumerable<bool> GetBools(YourClass obj)
{
return obj.GetType()
.GetProperties(BindingFlags.Public | BindingFlags.Instance)
.Where(x => x.PropertyType == typeof (bool))
.Select(x => (bool)x.GetValue(obj, null));
}
Then use LINQ to iterate through the collection, and create a dictionary of combinations and totals:
List<YourClass> objects = new List<YourClass>();
var totals = objects.GroupBy(x => String.Join(",", GetBools(x)))
.ToDictionary(x => x.Key, x => x.Count() / (double)objects.Count);
This will give you a dictionary with each unique combination and the percentage it occurs.
Given this input:
var o = new List<YourClass>
{
new YourClass {firstbool = true, secondbool = true, thirdbool = false},
new YourClass {firstbool = false, secondbool = false, thirdbool = false},
new YourClass {firstbool = true, secondbool = true, thirdbool = false}
};
The result in the dictionary will be:
{["True,True,False", 0.666666666666667]}
{["False,False,False", 0.333333333333333]}

it's probably easier to rewrite your class, storing each condition in an array like follows:
public class MyObject
{
public static int numFields = 20;
public enum Conditions
{
C1, C2, C3, .... C20 //name for each condition, so can set values using descriptive names
};
public Boolean[] BinaryFields = new Boolean[numFields];
public void setCondition(Conditions condition, Boolean value)
{
BinaryFields[(int)condition] = value;
}
public override string ToString()
{
return string.Join(",", BinaryFields);
}
}
then you can calculate the stat by counting what is actually there, instead of numerating through all of the 2^20 possibilities. something like follows:
static void Main(string[] args)
{
//simulation: creat 10 MyObjects
List<MyObject> lst = new List<MyObject>();
for (int i = 0; i < 10; i++)
{
MyObject m = new MyObject();
//example of setting condition
m.setCondition(MyObject.Conditions.C1, true);
lst.Add(m);
}
//calculate stat
var resultCount = new Dictionary<string, int>(); //conditionResult, count
foreach (MyObject m in lst)
{
if (resultCount.ContainsKey(m.ToString()))
{
resultCount[m.ToString()] += 1;
}
else
{
resultCount.Add(m.ToString(), 1);
}
}
//print stat
foreach(KeyValuePair<string, int> entry in resultCount){
Debug.WriteLine("probability for conditoin={0} is {1}", entry.Key, (double)entry.Value / lst.Count);
}
}

If you have some unique action for each boolean properties combination I suggest you to use some kind of string key for your object, generated on those values. Something like "001001", "000000" etc. Then use Dictionary<string, Func<int>> to hold all your unique actions, get and perform the right one by it's key. For example:
public class Object21
{
public int Id { get; set; }
public bool FirstBool { get; set; }
public bool SecondBool { get; set; }
public bool ThirdBool { get; set; }
public bool FourthBool { get; set; }
public bool FifthBool { get; set; }
public bool SixthBool { get; set; }
public void Process()
{
// Perform the action
Actions[Key]();
}
// Returns "001001" like representation of your object
public string Key
{
get
{
return string.Join(string.Empty, GetType()
.GetProperties(BindingFlags.Public | BindingFlags.Instance)
.Where(x => x.PropertyType == typeof(bool))
.Select(x => (bool)x.GetValue(this, null) ? "1" : "0" ));
}
}
private static Dictionary<string, Func<int>> Actions
{
get
{
return new Dictionary<string, Func<int>>
{
{"000000", new Func<int>(delegate
{
Console.WriteLine("000000 action performed.");
return 0;
})},
{"000001", new Func<int>(delegate
{
Console.WriteLine("000001 action performed.");
return 1;
})},
{"000010", new Func<int>(delegate
{
Console.WriteLine("000010 action performed.");
return 2;
})},
// More actions
{"111111", new Func<int>(delegate
{
Console.WriteLine("111111 action performed.");
return 63;
})}
};
}
}
}
And then use this in your program like this:
static void Main(string[] args)
{
var list = new List<Object21>
{
// initialize your list
};
foreach (var object21 in list)
{
object21.Process();
}
// Calculate your occurrences (basically what #Grant Winney suggested)
var occurrences = list.GroupBy(o => o.Key).ToDictionary(g => g.Key, g => (g.Count() / (double)list.Count)*100);
foreach (var occurrence in occurrences)
{
Console.WriteLine("{0}: {1}%", occurrence.Key, occurrence.Value);
}
}

How can I filter a collection so I get only the rows where the value of a fields is not null?

I have a call to GetData() that returns a collection of TQ:
IList<TQ> tq = _questionService.GetData();
public class TQ
{
// Index
public int i { get; set; }
// Text
public string text { get; set; }
}
How can I filter what's in tq and make another list where text is not null ?

_questionService.GetData().Where(x => x.text != null);
You might be interested in reading up on LINQ, it will be one of your most important tools in C# development.

If you can use LINQ you can use
var newList = tq.Where(p => p.text != null).ToList()
else something like that
var newList = new List<TQ>();
foreach(var element in tq) {
if (element.text != null) {
newList.Add(element);
}
}

Synchronize 2 lists

What is the best fastest way to Synchronize 2 Lists?
public class UserGroup
{
public UserGroup(string group, string user)
{
this.Group = group;
this.User = user;
}
public string Group { get; set; }
public string User { get; set; }
}
IList<UserGroup> userGroup1 = new IList<UserGroup>();
IList<UserGroup> userGroup2 = new IList<UserGroup>();
Each group has different number of members.
How can i find out the different and merge both in one new list?
PS: I can change the type from IList to whatever if it would be more efficient.
Thanks

So first we need an effective way of comparing these objects. Since the default Equals and GetHashCode implementations won't be useful in your context you either need to override them, or create an IEqualityComparer. I did the latter, you can feel free to do the former if you want. Here's a simple comparer:
public class UserGroupComparer : IEqualityComparer<UserGroup>
{
public bool Equals(UserGroup x, UserGroup y)
{
return x.Group == y.Group && x.User == y.User;
}
public int GetHashCode(UserGroup obj)
{
return 37 * obj.Group.GetHashCode() + 19 * obj.User.GetHashCode();
}
}
Now that you have this comparer you can leverage LINQ to do the work for you:
var combinedList = userGroup1.Union(userGroup2, new UserGroupComparer())
.ToList();
That will have all of the user groups that are in either list, but without any duplicates.

You can try:
userGroup1.Concat(userGroup2).Distinct();
And don't forget to override Equals and GetHashCode for UserGroup class.

The following could be used if the items in collections are of two different types:
class CollectionSynchronizer<TSource, TDestination>
{
public Func<TSource, TDestination, bool> CompareFunc { get; set; }
public Action<TDestination> RemoveAction { get; set; }
public Action<TSource> AddAction { get; set; }
public Action<TSource, TDestination> UpdateAction { get; set; }
public void Synchronizer(ICollection<TSource> sourceItems, ICollection<TDestination> destinationItems)
{
// Remove items not in source from destination
RemoveItems(sourceItems, destinationItems);
// Add items in source to destination
AddOrUpdateItems(sourceItems, destinationItems);
}
private void RemoveItems(ICollection<TSource> sourceCollection, ICollection<TDestination> destinationCollection)
{
foreach (var destinationItem in destinationCollection.ToArray())
{
var sourceItem = sourceCollection.FirstOrDefault(item => CompareFunc(item, destinationItem));
if (sourceItem == null)
{
RemoveAction(destinationItem);
}
}
}
private void AddOrUpdateItems(ICollection<TSource> sourceCollection, ICollection<TDestination> destinationCollection)
{
var destinationList = destinationCollection.ToList();
foreach (var sourceItem in sourceCollection)
{
var destinationItem = destinationList.FirstOrDefault(item => CompareFunc(sourceItem, item));
if (destinationItem == null)
{
AddAction(sourceItem);
}
else
{
UpdateAction(sourceItem, destinationItem);
}
}
}
}
And the usage would be like this:
var collectionSynchronizer = new CollectionSynchronizer<string, ContentImageEntity>
{
CompareFunc = (communityImage, contentImage) => communityImage == contentImage.Name,
AddAction = sourceItem =>
{
var contentEntityImage = _contentImageProvider.Create(sourceItem);
contentEntityImages.Add(contentEntityImage);
},
UpdateAction = (communityImage, contentImage) =>
{
_contentImageProvider.Update(contentImage);
},
RemoveAction = contentImage =>
{
contentEntityImages.Remove(contentImage);
}
};
collectionSynchronizer.Synchronizer(externalContentImages, contentEntityImages);

See the answer to this question: Create a list from two object lists with linq
Basically you can use this in System.Linq:
userGroup1.Union(userGroup2).ToList();

You may use HashSet see following link class http://msdn.microsoft.com/en-us/library/bb383091.aspx

Iterating over class properties using LINQ

There is a ParsedTemplate class that it has over 300 property (typed Details and BlockDetails). The parsedTemplate object will be fill by a function. After filling this object I need a LINQ (or other way) to find is there any property like "body" or "img" where IsExist=false and Priority="high".
public class Details
{
public bool IsExist { get; set; }
public string Priority { get; set; }
}
public class BlockDetails : Details
{
public string Block { get; set; }
}
public class ParsedTemplate
{
public BlockDetails body { get; set; }
public BlockDetails a { get; set; }
public Details img { get; set; }
...
}

You're going to need to write your own method to make this appetizing. Fortunately, it doesn't need to be long. Something like:
static IEnumerable<Details> GetDetails(ParsedTemplate parsedTemplate)
{
return from p in typeof(ParsedTemplate).GetProperties()
where typeof(Details).IsAssignableFrom(p.PropertyType)
select (Details)p.GetValue(parsedTemplate, null);
}
You could then, if you wanted to check if any property "exists" on a ParsedTemplate object, for example, use LINQ:
var existingDetails = from d in GetDetails(parsedTemplate)
where d.IsExist
select d;

If you really wanted to use linq while doing that, you could try something like that:
bool isMatching = (from prop in typeof(ParsedTemplate).GetProperties()
where typeof(Details).IsAssignableFrom(prop.PropertyType)
let val = (Details)prop.GetValue(parsedTemplate, null)
where val != null && !val.IsExist && val.Priority == "high"
select val).Any();
Works on my machine.
Or in extension method syntax:
isMatching = typeof(ParsedTemplate).GetProperties()
.Where(prop => typeof(Details).IsAssignableFrom(prop.PropertyType))
.Select(prop => (Details)prop.GetValue(parsedTemplate, null))
.Where(val => val != null && !val.IsExist && val.Priority == "high")
.Any();

Use c# reflection. For example:
ParsedTemplate obj;
PropertyInfo pi = obj.GetType().GetProperty("img");
Details value = (Details)(pi.GetValue(obj, null));
if(value.IsExist)
{
//Do something
}
I haven't compile but i think it work.

ParsedTemplate tpl = null;
// tpl initialization
typeof(ParsedTemplate).GetProperties()
.Where(p => new [] { "name", "img" }.Contains(p.Name))
.Where(p =>
{
Details d = (Details)p.GetValue(tpl, null) as Details;
return d != null && !d.IsExist && d.Priority == "high"
});