子窗体间事件调用

[hackerlyf]

我建了一个MDI窗体,这个窗体包含了几个子窗体,其中每个子窗体都会调用其它子窗体的事件
比如:父窗体打开一个子窗体A
子窗体A上的一个按钮又打开了一个子窗体B
子窗体B上的一个按钮现在想要调用子窗体A上的事件来执行一段代码,子窗体A和子窗体B上的事件应该怎么来定义和调用?

我是新手,请尽量写详细些!谢了

[dawugui]

在B的某处代码中写:

TriggerEven(子窗体A.控件名.事件名)

例如
TriggerEven(w_A.cb_1.Clicked!)

[dawugui]

TriggerEvent

Description 

Triggers an event associated with the specified object, which executes the script for that event immediately.

Controls 

Any object

Syntax 

objectname.TriggerEvent ( event {, word, long } )

Argument	Description
objectname	The name of any PowerBuilder object or control that has events associated with it.
event	A value of the TrigEvent enumerated datatype that identifies a PowerBuilder event (for example, Clicked!, Modified!, or DoubleClicked!) or a string whose value is the name of an event. The event must be a valid event for objectname and a script must exist for the event in objectname.
word (optional)	A long value to be stored in the WordParm property of the system's Message object. If you want to specify a value for long, but not word, enter 0. (For cross-platform compatibility, WordParm and LongParm are both longs.)
long 
 (optional)	A long value or a string that you want to store in the LongParm property of the system's Message object. When you specify a string, a pointer to the string is stored in the LongParm property, which you can access with the String function (see Usage).
Return value 

Integer. Returns 1 if it is successful and the event script runs and -1 if the event is not a valid event for objectname, or no script exists for the event in  objectname. If any argument's value is NULL, TriggerEvent returns NULL.

Usage 

If you specify the name of an event instead of a value of the TrigEvent enumerated datatype, enclose the name in double quotation marks.
Check return code   It is a good idea to check the return code to determine whether TriggerEvent succeeded and, based on the result, perform the appropriate processing.
You can pass information to the event script with the word and long arguments. The information is stored in the Message object. In your script, you can reference the WordParm and LongParm fields of the Message object to access the information.

If you have specified a string for long, you can access it in the triggered event by using the String function with the keyword "address" as the format parameter. Your event script might begin as follows:

string PassedString

PassedString = String(Message.LongParm, "address")

Caution  Do not use this syntax unless you are certain the long argument contains a valid string value.
For more information about events and when to use PostEvent and TriggerEvent, see PostEvent.
To trigger system events that are not PowerBuilder-defined events, use Post or Send, instead of PostEvent and TriggerEvent. Although Send can send messages that trigger PowerBuilder events, as shown below, you have to know the codes for a particular message. It is easier to use the PowerBuilder functions that trigger the desired events.

Equivalent syntax  
Both of the following statements click the CheckBox cb_OK. The following call to the Send function:

Send(Handle(Parent), 273, 0, Long(Handle(cb_OK), 0))

is equivalent to:

cb_OK.TriggerEvent(Clicked!)

This statement executes the script for the Clicked event in the CommandButton cb_OK immediately:

cb_OK.TriggerEvent(Clicked!)

This statement executes the script for the user-defined event cb_exit_request in the parent window:

Parent.TriggerEvent("cb_exit_request")

This statement executes the script for the Clicked event in the menu selection m_File on the menu m_Appl:

m_Appl.m_File.TriggerEvent(Clicked!)

[dawugui]

TriggerEvent

Description 

Triggers an event associated with the specified object, which executes the script for that event immediately.

Controls 

Any object

Syntax 

objectname.TriggerEvent ( event {, word, long } )

Argument	Description
objectname	The name of any PowerBuilder object or control that has events associated with it.
event	A value of the TrigEvent enumerated datatype that identifies a PowerBuilder event (for example, Clicked!, Modified!, or DoubleClicked!) or a string whose value is the name of an event. The event must be a valid event for objectname and a script must exist for the event in objectname.
word (optional)	A long value to be stored in the WordParm property of the system's Message object. If you want to specify a value for long, but not word, enter 0. (For cross-platform compatibility, WordParm and LongParm are both longs.)
long 
 (optional)	A long value or a string that you want to store in the LongParm property of the system's Message object. When you specify a string, a pointer to the string is stored in the LongParm property, which you can access with the String function (see Usage).
Return value 

Integer. Returns 1 if it is successful and the event script runs and -1 if the event is not a valid event for objectname, or no script exists for the event in  objectname. If any argument's value is NULL, TriggerEvent returns NULL.

Usage 

If you specify the name of an event instead of a value of the TrigEvent enumerated datatype, enclose the name in double quotation marks.
Check return code   It is a good idea to check the return code to determine whether TriggerEvent succeeded and, based on the result, perform the appropriate processing.
You can pass information to the event script with the word and long arguments. The information is stored in the Message object. In your script, you can reference the WordParm and LongParm fields of the Message object to access the information.

If you have specified a string for long, you can access it in the triggered event by using the String function with the keyword "address" as the format parameter. Your event script might begin as follows:

string PassedString

PassedString = String(Message.LongParm, "address")

Caution  Do not use this syntax unless you are certain the long argument contains a valid string value.
For more information about events and when to use PostEvent and TriggerEvent, see PostEvent.
To trigger system events that are not PowerBuilder-defined events, use Post or Send, instead of PostEvent and TriggerEvent. Although Send can send messages that trigger PowerBuilder events, as shown below, you have to know the codes for a particular message. It is easier to use the PowerBuilder functions that trigger the desired events.

Equivalent syntax  
Both of the following statements click the CheckBox cb_OK. The following call to the Send function:

Send(Handle(Parent), 273, 0, Long(Handle(cb_OK), 0))

is equivalent to:

cb_OK.TriggerEvent(Clicked!)

This statement executes the script for the Clicked event in the CommandButton cb_OK immediately:

cb_OK.TriggerEvent(Clicked!)

This statement executes the script for the user-defined event cb_exit_request in the parent window:

Parent.TriggerEvent("cb_exit_request")

This statement executes the script for the Clicked event in the menu selection m_File on the menu m_Appl:

m_Appl.m_File.TriggerEvent(Clicked!)

[LamarChen]

TriggerEvent
个人觉得 应该尽量少这样调用

[jdsnhan]

1、TriggerEvent 可以实现
2、怎样打开的窗口
3、最关键的，需求来源，为何B要调用A的事件。

[liubocy]

A打开B：open(B)或者用opensheet

B调用A的时间，如ue_aa：

if isvalid(A) then A.dynamic trigger event ue_aa()

[mmbest]

通俗一点就是，
你A打开B的时候，同时把A作为一个对象传过去。然后B可以调用A的函数，事件了。

[liubocy]

A中某按钮或事件中代码：

string ls_ret
open(B)
ls_ret = message.stringparm
...


B窗口选择某条数据后：
string ls_ret

ls_ret = dw_1.getitemstring(dw_1.getrow(), '列名')
closewithreturn(parent, ls_ret)

b窗口的类型为response

-----------
A中接收的ls_ret就是B窗口中要传的ls_ret

[hackerlyf]

楼上的,点击B窗口的按钮后提示 :Error:Null object reference at line 2 in clicked event of object cb_2 of b.

这种方式是不是只能返回一个参数?如果返回多个怎么办?

[liubocy]

那只是个参考，列名什么的自己代入就是了，照葫芦画瓢也不会吗。

要传多个参数，你可以拼接字符串啊，比如你要传“aa”和“1”这2个数据，你可以传“aa,1”过去，然后在拆分就是了

[mmbest]

这年头一定要把代码写完整才可以哦

A中某按钮代码：

w_sheet_class lw_parent
string ls_test
ls_test='w_sheet_3'//你的B窗口名字
OpenWithParm(lw_parent,parent,ls_test)

B中调用A事件
string lu_test
w_sheet_1 lw_sheet //你的A窗口
lw_sheet = Message.PowerObjectParm
lu_test="ue_test"//A中事件名字
lw_sheet.triggerevent(lu_test)//触发A中的事件

[hackerlyf]

可以了,刚才窗口太多搞错了!
谢谢楼上的各位了!呵呵

[hackerlyf]

我要的效果:
A子窗体是一张单据,在做的时候要查询另一个B子窗体单据的数据,所以要在子窗体A调用子窗体B,B子窗体查询完后选择其中的某条数据,然后把选择的结果返馈给B子窗体,并且要调用A子窗体的事件,更新A子窗体上的数据显示内容

[AFIC]

如果B窗体的类型是RESPONSE的，你可以用OPENWITHPAM,closewithreturn
如果b窗体类型不是response的，通常的设计是给b添加一个窗口类型的事例变量
在增加一个参数为window的of_setreserver的方法，方法就一句话
事例变量=参数
等到b想法消息的时候，事例变量.event dynamic 消息名（参数）
即可。

[hackerlyf]

楼上的,听你说的好像很有道理,我是新手,还没听懂,能不能说得更通俗更详细些