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ryoqiang 2002-09-19
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判断数据合法性
Determines whether an object variable is instantiated梬hether its value is a valid object handle.
Return value
Boolean. Returns a boolean value indicating whether objectname has been created. If objectname is NULL, IsValid returns NULL
Exp:
This statement determines whether the window w_emp is open and if it is not, opens it:
IF IsValid(w_emp) = FALSE THEN Open(w_emp)
Determines whether an object variable is instantiated梬hether its value is a valid object handle.
Return value
Boolean. Returns a boolean value indicating whether objectname has been created. If objectname is NULL, IsValid returns NULL
Exp:
This statement determines whether the window w_emp is open and if it is not, opens it:
IF IsValid(w_emp) = FALSE THEN Open(w_emp)
warchild 2002-09-19
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判断一个变量是否被例示化，是否是一个有效的句柄
通常用它取代handle函数来判断一个窗口是否被打开
IF IsValid(w_emp) = FALSE THEN Open(w_emp)
通常用它取代handle函数来判断一个窗口是否被打开
IF IsValid(w_emp) = FALSE THEN Open(w_emp)
liangshi001 2002-09-19
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判斷一個對象是否有效!
yang1105 2002-09-19
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我用来判断过窗口有没有打开。
