How to check if a given value is a general list?

Question

public bool IsList(object value) { Type type = value.GetType(); // Check if type is a generic list of any type } 

What is the best way to check if a given object is a list or can be added to a list?

Answer 1

 if(value is IList && value.GetType().IsGenericType) { } 

Answer 2

For you guys use extension methods:

 public static bool IsGenericList(this object o) { var oType = o.GetType(); return (oType.IsGenericType && (oType.GetGenericTypeDefinition() == typeof(List<>))); } 

So, we could do:

 if(o.IsGenericList()) { //... } 

Answer 3

  bool isList = o.GetType().IsGenericType && o.GetType().GetGenericTypeDefinition() == typeof(IList<>)); 

Answer 4

 if(value is IList && value.GetType().GetGenericArguments().Length > 0) { } 

Answer 5

 public bool IsList(object value) { return value is IList || IsGenericList(value); } public bool IsGenericList(object value) { var type = value.GetType(); return type.IsGenericType && typeof(List<>) == type.GetGenericTypeDefinition(); } 

Answer 6

Probably the best way is to do something like this:

 IList list = value as IList; if (list != null) { // use list in here } 

This will give you maximum flexibility and will also allow you to work with many different types that implement the IList interface.

Answer 7

Based on Victor Rodriguez’s answer, we can develop another method for generics. In fact, the original solution can be reduced to only two lines:

 public static bool IsGenericList(this object Value) { var t = Value.GetType(); return t.IsGenericType && t.GetGenericTypeDefinition() == typeof(List<>); } public static bool IsGenericList<T>(this object Value) { var t = Value.GetType(); return t.IsGenericType && t.GetGenericTypeDefinition() == typeof(List<T>); }