Valimai
asked on
.Net 2.0+ Reflect Generic List Type
hi there,
List<MyClass> list = new List<MyClass>();
Type t = list.GetType();
Console.Write(t.ToString);
Output: System.Collections.Generic
How can I get MyClass into "Type t" via the "list" variable?
List<MyClass> list = new List<MyClass>();
Type t = list.GetType();
Console.Write(t.ToString);
Output: System.Collections.Generic
How can I get MyClass into "Type t" via the "list" variable?
ASKER CERTIFIED SOLUTION
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ASKER
I ended up fixing the structure of my code using a generic class and did not need to use your solutions. However, they were quite valid in the context of the example. Thank you for your help!
Well, resently I had a situation similar to yours. I had a generic list (List <EItem>) and had to implement a comparer for it "public int Compare(EItem x, EItem y)" . The problem was that some of the properties of my object (EItem) were lists as well. As you can imagine comparing 2 lists is a little bit triky, so I have made an assumpition that I will compare only forst items x.ListProp[0] and y.ListProp[0] and I have used reflection in order to achieve that. I attache sample code below, may be it will give you some new ideas:
public class EItemComparer: IComparer<EItem>
{
private string _propertyToCompare;
public EItemComparer(string propertyToCompare)
{
_propertyToCompare = propertyToCompare;
}
public int Compare(EItem x, EItem y)
{
//Type itemType = x.GetType();
PropertyInfo eItemPropertyToCompareInfo = typeof(EItem).GetProperty(_propertyToCompare);
if (eItemPropertyToCompareInfo != null)
{
object eItemXPropertyToCompareValue = eItemPropertyToCompareInfo.GetValue(x, null);
object eItemYPropertyToCompareValue = eItemPropertyToCompareInfo.GetValue(y, null);
//if property is a Generic.List type we can not just copare collections
//instead first element value will be picked and compared
//if (eItemXPropertyToCompareValue.GetType().ToString().Contains("Generic.List"))
if (eItemXPropertyToCompareValue is IList)
{
//get Generic.List "Count" property info
PropertyInfo listPropertyCountPropertyInfo = eItemXPropertyToCompareValue.GetType().GetProperty("Count");
//if List has elements, set eItemXPropertyToCompareValue and eItemYPropertyToCompareValue to the
//first element in the List
int eItemXListPropertyCountPropertyValue = (int)listPropertyCountPropertyInfo.GetValue(eItemXPropertyToCompareValue, null);
eItemXPropertyToCompareValue = eItemXListPropertyCountPropertyValue > 0 ? ((IList)eItemXPropertyToCompareValue)[0] : null;
int eItemYListPropertyCountPropertyValue = (int)listPropertyCountPropertyInfo.GetValue(eItemYPropertyToCompareValue, null);
eItemYPropertyToCompareValue = eItemYListPropertyCountPropertyValue > 0 ? ((IList)eItemYPropertyToCompareValue)[0] : null;
}
return Comparer.DefaultInvariant.Compare(eItemXPropertyToCompareValue, eItemYPropertyToCompareValue);
}
else
{
throw new Exception(_propertyToCompare + " is not a valid property to sort on. It doesn't exist in the Class.");
}
}
}
//sort EItem List
EItemComparer cmp = new EItemComparer(sortExpression);
eItems.Sort(cmp);
ASKER
I was hoping that i could get it even if the collection is empty. It seems odd that I could not find a property of the List<> object which revealed the type it contains.