C# 使用int.TryParse,Convert.ToInt32,(int)将浮点类型转换整数时的区别

using  System;
public   class  DoubleToInt
{
     public   static   void  Main()
    {
        Test_DoubleToInt( 0.4 );
         Test_DoubleToInt( 0.5 );
        Console.ReadKey();
    }
     static   void  Test_DoubleToInt( double  _testNumber)
    {
         int  _i= 0 ;
         for ( int  i= 0 ;i< 10 ;i++)
        {
             if (i!= 0 ){
                _testNumber+= 1 ;
            }
            Console.WriteLine( string .Format( "(int){0}={1}" ,_testNumber,( int )(_testNumber)));
            
            Console.WriteLine( string .Format( "Convent.ToInt32({0})={1}" ,_testNumber,Convert.ToInt32(_testNumber)));
             //int.TryParse只有转换整数类型，其他返回为0
             int .TryParse(_testNumber.ToString(),  out  _i);
            Console.WriteLine( string .Format( "int.TryParse({0})={1}" ,_testNumber,_i));
        }
        Console.WriteLine( string .Empty);
    } }