This works fine:
var expectedType = typeof(string);
object value = "...";
if (value.GetType().IsAssignableFrom(expectedType))
{
...
}
But how do I check if value is a string array without setting expectedType to typeof(string[])? I want to do something like:
var expectedType = typeof(string);
object value = new[] {"...", "---"};
if (value.GetType().IsArrayOf(expectedType)) // <---
{
...
}
Is this possible?
Use Type.IsArray and Type.GetElementType() to check the element type of an array.
Type valueType = value.GetType();
if (valueType.IsArray && expectedType.IsAssignableFrom(valueType.GetElementType())
{
...
}
But beware of Type.IsAssignableFrom()! If you want to check for an exact match, you should check for equality (i.e. typeA == typeB). If you want to check if a given type is the type itself or a subclass/interface, then you should use Type.IsAssignableFrom():
typeof(BaseClass).IsAssignableFrom(typeof(ExpectedSubclass))
You can use extension methods (not that you have to but makes it more readable):
public static class TypeExtensions
{
public static bool IsArrayOf<T>(this Type type)
{
return type == typeof (T[]);
}
}
And then use:
Console.WriteLine(new string[0].GetType().IsArrayOf<string>());
The neatest and securest way to do it that found is using MakeArrayType:
var expectedType = typeof(string);
object value = new[] {"...", "---"};
if (value.GetType() == expectedType.MakeArrayType())
{
...
}
value.GetType().GetElementType() == typeof(string)
as an added bonus (but I'm not 100% sure. This is the code I use...)
var ienum = value.GetType().GetInterface("IEnumerable`1");
if (ienum != null) {
var baseTypeForIEnum = ienum.GetGenericArguments()[0]
}
with this you can look for List, IEnumerable... and get the T.
This is another sample,
using System;
using System.Collections.Generic;
public static class Program
{
public static void Main()
{
Type type = typeof(string[]);
// string[], int[], char[], List<MyData>, IList<MyData>, IEnumarable<MyData> =====> console write "True",
// string, int, MyData etc ==== does not write
if (type.IsGenericType && type.GetGenericTypeDefinition() == typeof(IList<>))
{
Type itemType = type.GetGenericArguments()[0];
Console.WriteLine("True");
}
if (type.IsGenericType && type.GetGenericTypeDefinition() == typeof(List<>))
{
Type itemType = type.GetGenericArguments()[0];
Console.WriteLine("True");
}
if (type.IsGenericType && type.GetGenericTypeDefinition() == typeof(IEnumerable<>))
{
Type itemType = type.GetGenericArguments()[0];
Console.WriteLine("True");
}
if (type.IsArray)
{
Console.WriteLine("True");
}
}
}
public class MyData
{
public string Name { get; set; }
}
Do you actually need to know the type of the array? Or do you only need the elements to be of a certain type?
If the latter, you can simply filter only the elements that match what you want:
string[] strings = array.OfType<string>();
if(objVal.GetType().Name == "Object[]")
true for array
