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  • 读书笔记之C#的is和as操作符强制类型转换收藏

    isBooleantruefalseis

    if(o is Employee)...{

    Employee e=(Employee) o;

    }

    CLRisoEmployeeifCLRoEmployeeCLRCLRoCLR(Employee)

    Employee e=o as Employee;

    if(e!=null)

    ...{}

    CLRoEmployee;asnulloEmployeeasnullasCLRifenull.

    asnullnullSystem.NullReferenceException

    c# isas

    isas2

    istruefalsetruefalseis

    System.Boolean b1 = (o is System.Object);//b1 true

    System.Boolean b2 = (o is Employee);//b2falsenullisfalse

    if(o is Employee) {

    Employee e = (Employee) o;

    //ife

    }clrisoemployeeifclroEmployeec#as,

    Employee e = o as Employee;

    if(e != null)

    {

    //ife

    }as1

    .net

    c#isas2008-03-18 18:43is as

    is : ,Bool,

    object o = new object();

    if (o is Label)

    {

    Label lb = (Label)o;

    Response.Write("");

    }

    else

    {

    Response.Write("");

    }

    ,CLR,is,oLable,(Label)o,,

    as:,,,null

    object o = new object();

    Label lb = o as Label;

    if (lb == null)

    {

    Response.Write("");

    }

    else

    {

    Response.Write("");

    }

    ,CLR, is

    eg

    _DoubleClick(object sender, EventArgs e)

    {

    (e as MouseEventArgs).Button == MouseButtons.Left;

    }

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  • 原文地址:https://www.cnblogs.com/williamzhao/p/2410605.html
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