Monthly Archives: August 2010

>C# – Returning a Generic List

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>Suppose I have a generic method that returns a generic list, code shows how you can do that.

public List<T> GetAll<T>() where T : class

{
   List<T> result;
   if (typeof(T) == typeof(MyObject))
   {
     result = new List<T>
      {
          new MyObject()
         {
            name = “ObjectName1”,
            id = 1
         } as T,
         new MyObject()

       {
          name = “ObjectName2”,
          id = 2
        } as T,
};
return result;
}
else //You can add other objects here if you’re using it in your Repository Test
{
return new List<T>();
}
}

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>C# – Getting Property value of an object using extension method

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>Code below illustrate how to process a list of T and validating or checking the value of one of the property of object T using C# 3.0 extension methods.

/// <summary>

/// Method that returns Value of Property from an Object
/// </summary>
/// <param name=”obj”></param>
/// <param name=”propertyName”></param>
/// <returns></returns>
public static string GetPropertyValue(this object obj, string propertyName)
{
if (obj == null)
{
throw new ArgumentNullException(“obj”);
}
PropertyInfo propertyInfo = obj.GetType().GetProperty(propertyName);
if (propertyInfo != null)
{
object prop = propertyInfo.GetValue(obj, null);
return prop.ToString();
}
else
{
return string.Empty;
}
}
 
 
Sample Usage:

/// <summary>

//////</summary>
[TestMethod()]
public void GetPropertyValueTest()
{
List<TestClass > list = new List<TestClass>
{
new TestClass
{
GUID = “Not this value”
},
new TestClass
{
GUID = “ThisValue”
}
};
ProcessList(list);
}


private void ProcessList<T>(List<T> list) where T: class
{
//Check the value of certain property in T object
var query = list.Find(i => i.GetPropertyValue(“GUID”) == “ThisValue”);
if(query != null)
{
//Match Found.. Do processing here
}
else
{
//No Match found..
}
}

C# – Unique List Collection

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C# – Unique List Collection

Ever wonder how you can create a unique list based on the certain criteria you’ve specified? See code below


/// <summary>

/// Unique Collection
/// </summary>
/// <typeparam name="T"></typeparam>
public class UniqueCollection <T> : List<T>
{
public UniqueCollection()
{
}
/// <summary>
/// Method that adds a new item if item is unique based on specified condition
/// </summary>
/// <param name="item"></param>
/// <param name="uniqueCheckCondition"></param>
/// <returns>Returns true if item is added to the collection</returns>
public bool AddUniqueValue(T item, Predicate<T> uniqueCheckCondition)
{
bool isAdded = true;
foreach(T i in this)
{
if (uniqueCheckCondition(i))
{
isAdded = false;
break;
}
}

if (isAdded)
{
this.Add(item);
}
return isAdded;
}
}

Sample use:


Guid dupGuid = Guid.NewGuid();

TestClass item1 = new TestClass
{
GUID = dupGuid.ToString() ,
SettingReference = "Test"
};

TestClass item2 = new TestClass
{
GUID = dupGuid.ToString(),
SettingReference = "Test"
};

UniqueCollection<TestClass> target = new UniqueCollection<TestClass>();
target.AddUniqueValue(item1, i => i.GUID == item1.GUID);
target.AddUniqueValue(item2, i => i.GUID == item2.GUID);
Assert.AreEqual(1, target.Count);