- Declaring a Control variable
- Assigning a Control variable
- Using a Control variable in a procedure
- Optimizing the processes with indirection
- Properties associated with a Control variable
- Functions that handle a Control variable
Control (Type of variable) In french: Champ
The Control type is used to define the characteristics of a control. This control can be dynamically created by ControlCreate or it can be a control found in a window or in a report. Remark: For more details on the declaration of this type of variable and the use of WLanguage properties, see Declaring a variable. Remarks Declaring a Control variable The following syntax is used to declare a Control variable:
<Variable Name> is Control
Assigning a Control variable A Control variable can be used to handle: - a control found in a window or in a report.
 a control created by ControlCreate.
The assignment of a Control variable must be performed by the '<-' operator. Examples:
// Assignment with an existing control
c is Control
c <- EDT_Edit1
// Assignment by using the indirection
// The variable references the EDT_EDIT2 control
c <- {"EDT_EDIT2"}
Caution: The '=' operator must not be used to assign a Control variable. This operator is used to transfer the value of a control into another control of the same type. For example:
// Assignment with an existing control
c is Control
c <- EDT_Edit1
// Modify the value
c = EDT_Edit3 // Equivalent code: EDT_Edit1.Value = EDT_Edit3.Value
c = "Text" // Equivalent code: EDT_Edit1.Value = "Text"
Remark: To know if a value has been assigned to the Control variable, use the Type property on the variable. Using a Control variable in a procedure The Control type can be a parameter of a procedure. You can write for example: - the code of the procedure:
PROCEDURE MyProcedure(C is Control)
C = "It is " + TimeSys()
- the call to the procedure:
Optimizing the processes with indirection The Control type can be used to optimize the processes that use the indirections. You can write for example:
C is Control <-{s, indControl}
C.Width = 10
C.Height = 20
rather than the following code:
{s, indControl}..Width = 10
{s, indControl}..Height = 20
Properties associated with a Control variable The Control type is used to handle all types of controls found in a window or in a report. The available properties depend on the type of control used. Therefore, if a Control variable is used to handle an edit control, all the WLanguage properties available for the edit control will be usable on the Control variable. To get the properties of a control, see the control help page: the "See Also" link is used to access all the control properties. For more details, see Window controls. Functions that handle a Control variable All the WLanguage functions that handle the controls can be used on a Control variable. However, only the WLanguage functions corresponding to the type of control used will be available. Therefore, the TableXXX functions can be used on a Control variable that handles a Table control.
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