首先你需要建立一个类库文件（编译后扩展名为.dll），名字假设为：reflection_newtest
系统会默认地新建一个类文件class1，把它该成我们用来测试的类person
具体代码如下：(类的代码比较简单，这里不做解释，如有不明之处，请查看类的相关文档.)
public class person
public firstname as string
public lastname as string
dim m_age as short
dim m_emailaddress(4) as string
public sub new()
mybase.new()
end sub
public sub new(byval firstname as string, byval lastname as string)
me.firstname = firstname
me.lastname = lastname
end sub
public property age() as short
get
return m_age
end get
set(byval value as short)
m_age = value
end set
end property
public property emailaddress(byval index as short) as string
get
return m_emailaddress(index)
end get
set(byval value as string)
m_emailaddress(index) = value
end set
end property
sub sendemail(byval msg as string, optional byval priorty as integer = 1)
console.writeline("message to " & firstname & " " & lastname)
console.writeline("priority " & priorty.tostring)
console.writeline(msg)
end sub
end class
二．测试验证的程序
建立一个winform的程序，命名假设为：testreflection
从工具栏里拖两个按钮，命名为button1,button2.
1．在程序的最上面加入引用：
imports system
imports system.reflection
imports system.type
2．在button1的click事件里写：
dim asm as [assembly] ‘由于assembly是关键字，所以要加[]
asm = reflection.assembly.loadfrom("g:/练习/reflection_newtest/bin/reflection_newtest.dll") ‘这里假设上面的reflection_newtest文件的位置在g:/练习 的文件夹。
console.writeline(asm.fullname) ‘输出完全限定名
console.writeline(asm.location) ‘获取该文件的基本代码格式的位置
console.writeline(asm.codebase) ‘获取最初指定的程序集的位置，一般来说和location方法很相似
dim mo as [module] ‘遍历模块
for each mo in asm.getmodules
console.writeline(mo.fullyqualifiedname)
next
dim ty as type
for each ty in asm.gettypes ‘遍历所有类型的信息
console.writeline(ty.fullname)
next
‘动态加载一个实例
dim o as object = asm.createinstance("reflection_newtest.person")
console.writeline("********************")
console.writeline(o.gettype.fullname)
说明： 这里的使用都比较简单，请继续往下看！
3．建立测试的过程
'获取遍历的类型，这里使用了系统类库文件mscorlib.dll
private sub testtypeenumeration()
dim asm as [assembly] = reflection.assembly.load("mscorlib")
dim t as type
for each t in asm.getexportedtypes ‘对于当前的文件的测试
if t.isclass then ‘如果是类
console.writeline(t.name & "(class)")
elseif t.isenum then ‘如果是枚举
console.writeline(t.name & "(enum)")
elseif t.isvaluetype then ‘如果是值类型
console.writeline(t.name & "(structure)")
elseif t.isinterface then ‘如果是接口
console.writeline(name & "(interface)")
else ‘其他
'没做处理
end if
next
end sub
'获取某一类型的所有信息(这里以string为例)
‘从上面的load与type.gettype可见，他们都是创建assembly的方式
private sub testatypememberinfo1()
dim stringtype as type = type.gettype("system.string") '获取指定名称的系统类型，也可以使用type.gettype(string)
dim minfos() as memberinfo ‘类型数组
dim mi as memberinfo
minfos = stringtype.getmembers
for each mi in minfos
console.writeline(mi.name)
next
'获得公共的非共享的并且是继承的成员
minfos = stringtype.getmembers(bindingflags.public or bindingflags.instance or bindingflags.declaredonly)
‘为了便于看清楚输出，做了间隔
console.writeline("*********************")
for each mi in minfos
console.writeline(mi.name)
next
‘同样的间隔设置
console.writeline("*********************")
'获取所有方法
for each mi in stringtype.getmethods
console.writeline(mi.name)
next
end sub
'使用特定的显示某一种类型的方法
private sub testatypememberinfo()
dim stringtype as type = type.gettype("system.string") '获取指定名称的系统类型
‘对于特定类型的属性的遍历
dim pinfos() as propertyinfo = stringtype.getproperties
dim mi as memberinfo
for each mi in pinfos
console.writeline(mi.name)
next
end sub
'使用findmember方法对类型的遍历1
private sub testfindmember1()
dim stringtype as type = type.gettype("system.string")
‘对于findmembers方法来说，它的参数分别为要获得的类型（可用or组合），筛选条件（可用or组合），
委托函数，传递给委托函数的参数。
dim minfos() as memberinfo = stringtype.findmembers(membertypes.method _
or membertypes.property, bindingflags.instance or bindingflags.public, _
addressof filterbyname1, "c")
dim mi as memberinfo
for each mi in minfos
console.writeline(mi.name)
next
end sub
'委托函数一：筛选那些是以c开头的公共的实例的方法和属性（这个函数一旦返回true，意味着是符合要求的）
private function filterbyname1(byval m as memberinfo, byval filtercriteria as object) as boolean
'如果成员名称以筛选函数的第2个参数开始，则返回true
if m.name.startswith(filtercriteria.tostring) then
return true
end if
end function
'使用findmember方法对类型的遍历2
private sub testfindmember2()
dim returntype as type = type.gettype("system.int32")
dim minfos() as memberinfo = returntype.findmembers(membertypes.method or membertypes.property, _
bindingflags.instance or bindingflags.public, addressof filterbyname2, returntype)
dim mi as memberinfo
for each mi in minfos
console.writeline(mi.name)
next
end sub
'委托函数二
private function filterbyname2(byval m as memberinfo, byval filtercriteria as object) as boolean
if m.membertype = membertypes.property then
dim pi as propertyinfo = ctype(m, propertyinfo)
return (pi.propertytype is filtercriteria) '如果该属性的类型与第2个参数相同则返回true
elseif m.membertype = membertypes.method then
dim mi as methodinfo = ctype(m, methodinfo)
return (mi.returntype is filtercriteria) '如果该方法的返回类型与第2个参数相同则返回true
end if
end function
'关于重载函数的调用
private sub testoverloadmemberinfo()
dim stringtype as type = type.gettype("system.string")
'一个类型数组
dim argtypes() as type = {type.gettype("system.string"), type.gettype("system.string")}
dim mi as memberinfo = stringtype.getmethod("compare", argtypes)
console.writeline(mi.name)
end sub
'枚举参数类型
private sub testcallingsyntax()
dim stringtype as type = type.gettype("system.string")
dim mi as methodinfo = stringtype.getmethod("copy")
dim pinfos() as parameterinfo = mi.getparameters
dim i as integer
'列出参数和参数的类型,中间用/连接
for i = 0 to pinfos.getupperbound(0)
console.writeline(pinfos(i).name & "/" & pinfos(i).parametertype.tostring)
next
end sub
'使用反射创建实例并给属性赋值
private sub testreadwriteproperties()
try
dim asm as [assembly] = reflection.assembly.loadfrom("g:/练习/reflection_newtest/bin/reflection_newtest.dll")
dim ty as type = asm.gettype("reflection_newtest.person")
dim m as object = activator.createinstance(ty)
dim pi as propertyinfo = ty.getproperty("age")
pi.setvalue(m, 5s, nothing) '一定要指定赋值的类型，如是short类型，一定要加s
console.writeline(pi.getvalue(m, nothing))
catch ex as exception
messagebox.show(ex.message)
end try
end sub
'测试字符串属性(且含参数)
private sub testreadwritepropertytieswithargs()
try
dim asm as [assembly] = reflection.assembly.loadfrom("g:/练习/reflection_newtest/bin/reflection_newtest.dll")
dim ty as type = asm.gettype("reflection_newtest.person")
dim m as object = activator.createinstance(ty)
dim pi as propertyinfo = ty.getproperty("emailaddress")
dim params() as object = {1s} '注意参数类型的严格匹配
pi.setvalue(m, "
console.writeline(pi.getvalue(m, params))
catch ex as exception
messagebox.show(ex.message)
end try
end sub
'使用invoke方法测试过程
private sub testinvokemethod()
dim asm as [assembly] = reflection.assembly.loadfrom("g:/练习/reflection_newtest/bin/reflection_newtest.dll")
dim ty as type = asm.gettype("reflection_newtest.person")
dim m as object = activator.createinstance(ty)
dim mi as methodinfo = ty.getmethod("sendemail")
'定义过程的参数数组
dim params(mi.getparameters.length - 1) as object
try
params(0) = "this is message"
params(1) = 3
'触发过程
mi.invoke(m, params)
catch ex as exception
messagebox.show(ex.message)
end try
end sub
'使用invokemember方法测试过程
private sub testinvokemember()
dim asm as [assembly] = reflection.assembly.loadfrom("g:/练习/reflection_newtest/bin/reflection_newtest.dll")
dim ty as type = asm.gettype("reflection_newtest.person")
dim m as object = activator.createinstance(ty)
dim args() as object = {"francesco"}
try
'设置firstname字段值
ty.invokemember("firstname", bindingflags.setfield, nothing, m, args)
'读取firstname字段值，这个时候不用最后一个参数
dim value as object = ty.invokemember("firstname", bindingflags.getfield, nothing, m, nothing)
console.writeline(value.tostring)
dim args2() as object = {35s} '注意这里的数组元素的类型一定要严格匹配short类型,
'设置属性值，参数意味着是属性的参数
ty.invokemember("age", bindingflags.setproperty, nothing, m, args2)
'读取属性值
dim value1 as object = ty.invokemember("age", bindingflags.getproperty, nothing, m, nothing)
console.writeline(value1.tostring)
dim args3() as object = {"this is a message", 2}
'触发过程
ty.invokemember("sendemail", bindingflags.invokemethod, nothing, m, args3)
catch ex as exception
messagebox.show(ex.message)
end try
end sub
‘///////////////////////////////////////////////////////////
'动态地创建对象(使用默认地构造函数)
private sub testobjectcreation1()
dim asm as [assembly] = reflection.assembly.loadfrom("g:/练习/reflection_newtest/bin/reflection_newtest.dll")
dim ty as type = asm.gettype("reflection_newtest.person")
try
dim m as object = activator.createinstance(ty)
console.writeline("a {0} object has been created ", m.gettype.name)
catch ex as exception
messagebox.show(ex.message)
end try
end sub
'使用带参数的方法(使用带参数的构造函数)
private sub testobjectcreation2()
dim asm as [assembly] = reflection.assembly.loadfrom("g:/练习/reflection_newtest/bin/reflection_newtest.dll")
dim ty as type = asm.gettype("reflection_newtest.person")
dim params() as object = {"joe", "doe"}
try
dim o as object = system.activator.createinstance(ty, params)
console.writeline(o.gettype.name)
catch ex as exception
messagebox.show(ex.message)
end try
end sub
'使用调用构造函数的方法来创建对象（实例）这个方法相对来说比较烦琐和麻烦。
private sub testobjectcreation3()
dim asm as [assembly] = reflection.assembly.loadfrom("g:/练习/reflection_newtest/bin/reflection_newtest.dll")
dim ty as type = asm.gettype("reflection_newtest.person")
dim types() as type = {gettype(system.string), gettype(string)}
dim ci as constructorinfo = ty.getconstructor(types) '获得这个有两个字符串参数的构造函数的信息
dim params() as object = {"joe", "doe"} '用来初始化的数组
dim o as object = ci.invoke(params) '执行这个构造函数
console.writeline(o.gettype.name)
end sub
4. button2的click事件中写：（该操作就是验证所有的测试过程，为了分辨出是哪个过程的结果，把其他的都暂时注释掉了。你可以根据需要来消除注释。）
'testtypeenumeration()
'testatypememberinfo1()
'testatypememberinfo2()
'testfindmember1()
'testfindmember2()
testoverloadmemberinfo()
'testcallingsyntax()
'testreadwriteproperties()
'testreadwritepropertytieswithargs()
'testinvokemethod()
'testinvokemember()
'testobjectcreation1()
'testobjectcreation2()
'testobjectcreation3()
说明：这里不多做过多地解释，代码中有比较完整的注释。如果有什么疏漏和错误，请指出！谢谢！
相关名词的简单说明： 反射（reflection）：.net中获取运行时类型信息的方式程序集（assembly）：编译后的.dll和exe文件。可以获得正在运行的装配件信息，也可以动态的加载装配件，以及在装配件中查找类型信息，并创建该类型的实例。类型（type）：这里的类型区分于值类型与引用类型中的类型，它包括类，枚举，值类型，接口等。菜鸟学堂：
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