Mega Code Archive
0392 Cast
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Cast accepts a nongeneric IEnumerable collection and emit a generic IEnumerable<T> sequence that you can subsequently query:
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
class Program
{
static void Main()
{
ArrayList classicList = new ArrayList(); // in System.Collections
classicList.AddRange(new int[] { 3, 4, 5 });
IEnumerable<int> sequence1 = classicList.Cast<int>();
foreach (int i in sequence1)
{
Console.WriteLine(i);
}
}
}
The output:
3
4
5
When encountering an incompatible type Cast throws an exception;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
class Program
{
static void Main()
{
ArrayList classicList = new ArrayList(); // in System.Collections
DateTime offender = DateTime.Now;
classicList.Add(offender);
IEnumerable<int> sequence1 = classicList.Cast<int>(); // Throws exception
foreach (int i in sequence1)
{
Console.WriteLine(i);
}
}
}
The output:
Unhandled Exception: System.InvalidCastException: Specified cast is not valid.
at System.Linq.Enumerable.d__b1`1.MoveNext()
at Program.Main() in c:\g\Program.cs:line 15
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