How to validate values in a list of object?

Question

I have a List<ObjectA> populated. Class ObjectA has two properties -string property1 bool? property2

[1]I need to loop through the entire list to check if property1 contains a particular string say 'xyz'.

[2] I need to check if value of property2 is true(which i believe i can figure out after getting to know how to handle [1])

thanks Adarsh

Answer 1

With List<T> you can also use its method TrueForAll:

bool valid = list.TrueForAll(a => a.property1.Contains("xyz") && a.property2);

This will work on any version of .NET >= 2.0. You also can use LINQ as @Hassan suggested:

bool valid = list.All(a => a.property1.Contains("xyz") && a.property2);

That will work on .NET >= 3.5. Benefit of this option is ability to work with any enumerable source (i.e. if you'll change list to ICollection, or some other enumerable type).

Answer 2

if you want to make sure if all elements of a particular collection satisfy a condition you can use All method in Linq, like this:

 new List<MyClass>().All(m => m.StringProp.Contains("ss") && m.IsValid == true)

Answer 3

Use LINQ:

List<ObjectA> list;

//Check for string
if (list.Any(a => a.property1.Contains("xyz")))
{

}

// Check for true
if (list.Any(a => a.property2 ?? false))
{

}

If you need to get the objects that satisfies your conditions, use list.Where(...)

Answer 4

There are several possible checks and results you can easily get.

void Main()
{       //ignore Dump() method
    var list = new List<ObjectA>() 
    {
        new ObjectA("name1", true),
        new ObjectA("name2", true),
        new ObjectA("name3", null),
        new ObjectA("name4", false),
        new ObjectA("name5", null),
        new ObjectA("name6", false),
        new ObjectA("name7", true)
    };
    //check if all Items are valid
var allItems = list.All(m => m.Name.Contains("ss") && m.valid == true); // false
    //only get valid items (name contains name AND true)
var validItems = list.Where (l => l.Name.Contains("name") && l.valid == true).Dump();
    //get all items which are invalid
var nonvalidItems = list.Where(l =>!(l.Name.Contains("name")) || l.valid != true).Dump();

}

public class ObjectA
{
  public ObjectA(string name, bool? _val)
  {
    this.Name = name;
    if(_val.HasValue)
      this.valid = _val;
  }
 public string Name { get; set; }
 public bool? valid { get; set; }
}