当类名作为变量传递时，实例化类的最佳方法是什么？

谢谢， Brian I have many similar classes in a project, one for each type of reportmy app can create. I want to instantiate them based on a value passedin by a scheduler module. Right now I have Sub RunReports(sReport)Select Case sReportCase "CRByDistrict"oReport = New CRByDistrict Case "CRCareConversionRate"oReport = New CRCareConversionRate Case (etc.....)End Select oReport.Build '' All classes implement a Build methodEnd Sub For example, if the scheduler says it''s time to run the "CRByDistrict"report I want to pass in "CRByDistrict" and invoke oReport = New <className> '' One line handles all reports where in this case <className> is "CRByDistrict". I''ve looked atActivator.CreateInstance and some other things, but I can''t figure outthe best, simplest way to do this. I''m tired of maintaining what has become a huge Select Case statementeach time I add a new report (class). Thanks,Brian推荐答案 恕我直言，Activactor.CreateInstance应该是你的选择。既然你已经在同一个项目中拥有了所有的类（因此也是相同的程序集），那么使用这种方法就可以非常简单了。类似于： dim reportType = Type.GetType（sReport） dim reportObject = Activator.CreateInstance（reportType） 或 dim reportObject = Activator.CreateInstance（Nothing，sReport） 希望有所帮助.. Imran。 " Brian" <峰; br ****** @ hotmail.com>在消息中写道 news：b6 ************************** @ posting.google.c om ... IMHO, Activactor.CreateInstance should be the way to go for you. Since youhave all your classes in the same project (and hence the same assembly), itshould be pretty simple to use this method. Something like: dim reportType = Type.GetType(sReport)dim reportObject = Activator.CreateInstance(reportType) Or dim reportObject = Activator.CreateInstance(Nothing, sReport) hope that helps..Imran. "Brian" <br******@hotmail.com> wrote in messagenews:b6**************************@posting.google.c om...我在项目中有很多类似的类，每个类型的报告都有一个我的应用可以创建的类。我想基于调度程序模块传递的值来实例化它们。 现在我有了Sub RunReports（sReport）选择案例报告案例CRByDistrict oReport =新CRByDistrict 案例CRCareConversionRate oReport =新CRCareConversionRate 案例（等等.....）结束选择 oReport.Build''所有类实现Build方法 End Sub 例如，如果调度程序表示现在是时候运行我要传入的CRByDistrict报告CRByDistrict了。并调用 oReport = New< className> ''一行处理所有报告 在这种情况下< className>是CRByDistrict。我已经看过了 Activator.CreateInstance和其他一些东西，但我无法弄明白这是最好，最简单的方法。 我是'我厌倦了维护已成为巨大的Select Case声明每次我添加一个新的报告（类）。 谢谢， Brian I have many similar classes in a project, one for each type of report my app can create. I want to instantiate them based on a value passed in by a scheduler module. Right now I have Sub RunReports(sReport) Select Case sReport Case "CRByDistrict" oReport = New CRByDistrict Case "CRCareConversionRate" oReport = New CRCareConversionRate Case (etc.....) End Select oReport.Build '' All classes implement a Build method End Sub For example, if the scheduler says it''s time to run the "CRByDistrict" report I want to pass in "CRByDistrict" and invoke oReport = New <className> '' One line handles all reports where in this case <className> is "CRByDistrict". I''ve looked at Activator.CreateInstance and some other things, but I can''t figure out the best, simplest way to do this. I''m tired of maintaining what has become a huge Select Case statement each time I add a new report (class). Thanks, Brian 在文章< b6 ************************** @ posting.google.com> ，Brian写道：In article <b6**************************@posting.google.com >, Brian wrote:我在项目中有很多类似的类，每个类型的报告都有一个我的应用可以创建的类。我想基于调度程序模块传递的值来实例化它们。 现在我有了Sub RunReports（sReport）选择案例报告案例CRByDistrict oReport =新CRByDistrict 案例CRCareConversionRate oReport =新CRCareConversionRate 案例（等等.....）结束选择 oReport.Build''所有类实现Build方法 End Sub 例如，如果调度程序表示现在是时候运行我要传入的CRByDistrict报告CRByDistrict了。并调用 oReport = New< className> ''一行处理所有报告 在这种情况下< className>是CRByDistrict。我已经看过了 Activator.CreateInstance和其他一些东西，但我无法弄明白这是最好，最简单的方法。 我是'我厌倦了维护已成为巨大的Select Case声明每次我添加一个新的报告（类）。 谢谢， Brian I have many similar classes in a project, one for each type of report my app can create. I want to instantiate them based on a value passed in by a scheduler module. Right now I have Sub RunReports(sReport) Select Case sReport Case "CRByDistrict" oReport = New CRByDistrict Case "CRCareConversionRate" oReport = New CRCareConversionRate Case (etc.....) End Select oReport.Build '' All classes implement a Build method End Sub For example, if the scheduler says it''s time to run the "CRByDistrict" report I want to pass in "CRByDistrict" and invoke oReport = New <className> '' One line handles all reports where in this case <className> is "CRByDistrict". I''ve looked at Activator.CreateInstance and some other things, but I can''t figure out the best, simplest way to do this. I''m tired of maintaining what has become a huge Select Case statement each time I add a new report (class). Thanks, Brian 我假设所有报告类都实现了特定的 接口或从公共基类继承 - 但对于这个例子 我''假设一个名为IReport的接口定义了Build方法。 鉴于上述情况，这样的事情应该有效： Private Sub RunReport（ByVal） ReportType As String） Dim report As IReport = DirectCast _ （Activator.CreateInstance（Type.GetType（ReportType）），_ IReport ） report.Build（） 结束子 - Tom Shelton [MVP] I am assuming that all of the report classes implement a specificinterface or inherit from a common base class - but for this exampleI''ll assume an interface named IReport that has the Build method defined.Given the above, something like this should work: Private Sub RunReport (ByVal ReportType As String)Dim report As IReport = DirectCast _(Activator.CreateInstance (Type.GetType (ReportType)), _IReport) report.Build() End Sub --Tom Shelton [MVP] oops..that wouldn 甚至编译;-) 我的意思是： dim reportType As Type = Type.GetType（sReport） dim reportObject As Object = Activator.CreateInstance（reportType） 或 dim reportObject as Object = Activator.CreateInstance（Nothing ，sReport） " Imran Koradia" <无**** @ microsoft.com>在消息中写道 新闻：％2 **************** @ TK2MSFTNGP10.phx.gbl ... oops..that wouldn''t even compile ;-) I meant: dim reportType As Type = Type.GetType(sReport)dim reportObject As Object = Activator.CreateInstance(reportType) Or dim reportObject as Object = Activator.CreateInstance(Nothing, sReport) "Imran Koradia" <no****@microsoft.com> wrote in messagenews:%2****************@TK2MSFTNGP10.phx.gbl...恕我直言， Activactor.CreateInstance应该是你的方式。既然你把所有的类放在同一个项目中（因此同一个程序集），使用这个方法应该非常简单。类似于： dim reportType = Type.GetType（sReport） dim reportObject = Activator.CreateInstance（reportType） 或 dim reportObject = Activator.CreateInstance（Nothing，sReport） 希望有所帮助.. Imran。 Brian <峰; br ****** @ hotmail.com>在消息中写道新闻：b6 ************************** @ posting.google.c om ... IMHO, Activactor.CreateInstance should be the way to go for you. Since you have all your classes in the same project (and hence the same assembly),it should be pretty simple to use this method. Something like: dim reportType = Type.GetType(sReport) dim reportObject = Activator.CreateInstance(reportType) Or dim reportObject = Activator.CreateInstance(Nothing, sReport) hope that helps.. Imran. "Brian" <br******@hotmail.com> wrote in message news:b6**************************@posting.google.c om...我在项目中有很多类似的类，每个类型的报告都有一个我的应用可以创建的类。我想基于调度程序模块传递的值来实例化它们。 现在我有了Sub RunReports（sReport）选择案例报告案例CRByDistrict oReport =新CRByDistrict 案例CRCareConversionRate oReport =新CRCareConversionRate 案例（等等.....）结束选择 oReport.Build''所有类实现Build方法 End Sub 例如，如果调度程序表示现在是时候运行我要传入的CRByDistrict报告CRByDistrict了。并调用 oReport = New< className> ''一行处理所有报告 在这种情况下< className>是CRByDistrict。我已经看过了 Activator.CreateInstance和其他一些东西，但我无法弄明白这是最好，最简单的方法。 我是'我厌倦了维护已成为巨大的Select Case声明每次我添加一个新的报告（类）。 谢谢， Brian I have many similar classes in a project, one for each type of report my app can create. I want to instantiate them based on a value passed in by a scheduler module. Right now I have Sub RunReports(sReport) Select Case sReport Case "CRByDistrict" oReport = New CRByDistrict Case "CRCareConversionRate" oReport = New CRCareConversionRate Case (etc.....) End Select oReport.Build '' All classes implement a Build method End Sub For example, if the scheduler says it''s time to run the "CRByDistrict" report I want to pass in "CRByDistrict" and invoke oReport = New <className> '' One line handles all reports where in this case <className> is "CRByDistrict". I''ve looked at Activator.CreateInstance and some other things, but I can''t figure out the best, simplest way to do this. I''m tired of maintaining what has become a huge Select Case statement each time I add a new report (class). Thanks, Brian 这篇关于当类名作为变量传递时，实例化类的最佳方法是什么？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！