[c#] Better way to cast object to int

This is probably trivial, but I can't think of a better way to do it. I have a COM object that returns a variant which becomes an object in C#. The only way I can get this into an int is

int test = int.Parse(string.Format("{0}", myobject))

Is there a cleaner way to do this? Thanks

I am listing the difference in each of the casting ways. What a particular type of casting handles and it doesn't?

    // object to int
    // does not handle null
    // does not handle NAN ("102art54")
    // convert value to integar
    int intObj = (int)obj;

    // handles only null or number
    int? nullableIntObj = (int?)obj; // null
    Nullable<int> nullableIntObj1 = (Nullable<int>)obj; // null

   // best way for casting from object to nullable int
   // handles null 
   // handles other datatypes gives null("sadfsdf") // result null
    int? nullableIntObj2 = obj as int?; 

    // string to int 
    // does not handle null( throws exception)
    // does not string NAN ("102art54") (throws exception)
    // converts string to int ("26236")
    // accepts string value
    int iVal3 = int.Parse("10120"); // throws exception value cannot be null;

    // handles null converts null to 0
    // does not handle NAN ("102art54") (throws exception)
    // converts obj to int ("26236")
    int val4 = Convert.ToInt32("10120"); 

    // handle null converts null to 0
    // handle NAN ("101art54") converts null to 0
    // convert string to int ("26236")
    int number;

    bool result = int.TryParse(value, out number);

    if (result)
    {
        // converted value
    }
    else
    {
        // number o/p = 0
    }

var intTried = Convert.ChangeType(myObject, typeof(int)) as int?;

Strange, but the accepted answer seems wrong about the cast and the Convert in the mean that from my tests and reading the documentation too it should not take into account implicit or explicit operators.

So, if I have a variable of type object and the "boxed" class has some implicit operators defined they won't work.

Instead another simple way, but really performance costing is to cast before in dynamic.

(int)(dynamic)myObject.

You can try it in the Interactive window of VS.

public class Test
{
  public static implicit operator int(Test v)
  {
    return 12;
  }
}

(int)(object)new Test() //this will fail
Convert.ToInt32((object)new Test()) //this will fail
(int)(dynamic)(object)new Test() //this will pass

Use Int32.TryParse as follows.

  int test;
  bool result = Int32.TryParse(value, out test);
  if (result)
  {
     Console.WriteLine("Sucess");         
  }
  else
  {
     if (value == null) value = ""; 
     Console.WriteLine("Failure");
  }

Maybe Convert.ToInt32.

Watch out for exception, in both cases.

The cast (int) myobject should just work.

If that gives you an invalid cast exception then it is probably because the variant type isn't VT_I4. My bet is that a variant with VT_I4 is converted into a boxed int, VT_I2 into a boxed short, etc.

When doing a cast on a boxed value type it is only valid to cast it to the type boxed. Foe example, if the returned variant is actually a VT_I2 then (int) (short) myObject should work.

Easiest way to find out is to inspect the returned object and take a look at its type in the debugger. Also make sure that in the interop assembly you have the return value marked with MarshalAs(UnmanagedType.Struct)

You can first cast object to string and then cast the string to int; for example:

string str_myobject = myobject.ToString();
int int_myobject = int.Parse(str_myobject);

this worked for me.

Convert.ToInt32(myobject);

This will handle the case where myobject is null and return 0, instead of throwing an exception.

int i = myObject.myField.CastTo<int>();

There's also TryParse.

From MSDN:

private static void TryToParse(string value)
   {
      int number;
      bool result = Int32.TryParse(value, out number);
      if (result)
      {
         Console.WriteLine("Converted '{0}' to {1}.", value, number);         
      }
      else
      {
         if (value == null) value = ""; 
         Console.WriteLine("Attempted conversion of '{0}' failed.", value);
      }
   }