การตรวจว่า report กำลังเปิดอยู่หรือไม่

เมื่อสั่งเปิด Report จาก Form ถ้าสั่งเปิด Report ไปครั้งหนึ่งแล้ว และจะสั่งใหม่อีก Report ที่ถูกเปิดไว้จะไม่ปิด และ เมื่อสั่งเปิดใหม่ ข้อมูลก็จะเป็นข้อมูลเก่า จึงดูเหมือนว่าไม่มีอะไรเปลี่ยน ทั้ง ๆ ที่ข้อมูลอาจจะเปลี่ยน

ดังนั้น การสั่งจากฟอร์ม ให้เปิดรายงาน จึงควรตรวจสอบก่อนว่า ฟอร์ม กำลังเปิดอยู่หรือไม่ ถ้ากำลังเปิดอยู่ก็สั่งให้ปิดเสีย

การตรวจว่า Report กำลังเปิดอยุ่หรือไม่ ให้ใช้คำสั่ง SysCmd เช่น

ถ้าต้องการตรวจสอบว่า รายงานชื่อ rptWF_viewPayment กำลังเปิดอยุ่หรือไม่ ถ้าเปิด ก็ให้ปิดเสีย ใช้คำสั่ง ดังนี้

If SysCmd(acSysCmdGetObjectState, acReport, “rptWF_viewPayment”) <> 0 Then
DoCmd.Close acReport, “rptWF_viewPayment”, acSaveNo
End If

สำหรับ object อาจจะใช้คำหรือตัวเลข ต่อไปนี้
Table acTable 0
Query acQuery 1
Form acForm 2
Report acReport 3
Macro acMacro 4
Module acModule 5
Data Access Page acDataAccessPage 6

ค่าที่ส่งออกมา เมื่อใช้ cmdSys() ตรวจสอบสถานะของ Object มีดังนี้
0 – object is closed or doesn’t exist
1 – Open acObjStateOpen
2 – Changed but not saved
acObjStateDirty
4 – New acObjStateNew

อ่านเพิ่มเติมที่
http://blogs.techrepublic.com.com/msoffice/?p=387

และที่
http://msdn.microsoft.com/en-us/library/aa221609(office.11).aspx

Access
SysCmd Method [Access 2003 VBA Language Reference]
You can use the SysCmd method to, display a progress meter or optional specified text in the status bar, return information about Microsoft Access and its associated files, or return the state of a specified database object (to indicate whether the object is open, is a new object, or has been changed but not saved). Variant.

expression.SysCmd(Action, Argument2, Argument3)

expression Required. An expression that returns one of the objects in the Applies To list.

AcSysCmdAction
AcSysCmdAction can be one of these AcSysCmdAction constants.
acSysCmdAccessDir. Returns the name of the directory where Msaccess.exe is located.
acSysCmdAccessVer. Returns the version number of Microsoft Access.
acSysCmdClearHelpTopic
acSysCmdClearStatus. The following constant provides information on the state of a database object.
acSysCmdGetObjectState. Returns the state of the specified database object. You must specify argument1 and argument2 when you use this action value.
acSysCmdGetWorkgroupFile. Returns the path to the workgroup file (System.mdw).
acSysCmdIniFile. Returns the name of the .ini file associated with Microsoft Access.
acSysCmdInitMeter. Initializes the progress meter. You must specify the argument1 and argument2 arguments when you use this action.
acSysCmdProfile. Returns the /profile setting specified by the user when starting Microsoft Access from the command line.
acSysCmdRemoveMeter. Removes the progress meter.
acSysCmdRuntime. Returns True (–1) if a run-time version of Microsoft Access is running.
acSysCmdSetStatus. Sets the status bar text to the text argument.
acSysCmdUpdateMeter. Updates the progress meter with the specified value. You must specify the text argument when you use this action.

Argument2 Optional Variant. A string expression identifying the text to be displayed left-aligned in the status bar. This argument is required when the action argument is acSysCmdInitMeter, acSysCmdUpdateMeter, or acSysCmdSetStatus; this argument isn’t valid for other action argument values.

acObjectType
acTable
acQuery
acForm
acReport

acMacro

acModule

acDataAccessPage

acDefault

acDiagram

acServerView

acStoreProcedure

This argument isn’t valid for other action argument values.

Argument3 Optional Variant. A numeric expression that controls the display of the progress meter. This argument is required when the action argument is acSysCmdInitMeter; this argument isn’t valid for other action argument values.

Note When you specify the acSysCmdGetObjectState value for the Action parameter, then you must specify the name of the database object.

Remarks
For example, if you are building a custom wizard that creates a new form, you can use the SysCmd method to display a progress meter indicating the progress of your wizard as it constructs the form.

By calling the SysCmd method with the various progress meter actions, you can display a progress meter in the status bar for an operation that has a known duration or number of steps, and update it to indicate the progress of the operation.

To display a progress meter in the status bar, you must first call the SysCmd method with the acSysCmdInitMeter action argument, and the text and value arguments. When the action argument is acSysCmdInitMeter, the value argument is the maximum value of the meter, or 100 percent.

To update the meter to show the progress of the operation, call the SysCmd method with the acSysCmdUpdateMeter action argument and the value argument. When the action argument is acSysCmdUpdateMeter, the SysCmd method uses the value argument to calculate the percentage displayed by the meter. For example, if you set the maximum value to 200 and then update the meter with a value of 100, the progress meter will be half-filled.

You can also change the text that’s displayed in the status bar by calling the SysCmd method with the acSysCmdSetStatus action argument and the text argument. For example, during a sort you might change the text to “Sorting…”. When the sort is complete, you would reset the status bar by removing the text. The text argument can contain approximately 80 characters. Because the status bar text is displayed by using a proportional font, the actual number of characters you can display is determined by the total width of all the characters specified by the text argument.

As you increase the width of the status bar text, you decrease the length of the meter. If the text is longer than the status bar and the action argument is acSysCmdInitMeter, the SysCmd method ignores the text and doesn’t display anything in the status bar. If the text is longer than the status bar and the action argument is acSysCmdSetStatus, the SysCmd method truncates the text to fit the status bar.

You can’t set the status bar text to a zero-length string (” “). If you want to remove the existing text from the status bar, set the text argument to a single space. The following examples illustrate ways to remove the text from the status bar:

varReturn = SysCmd(acSysCmdInitMeter, ” “, 100)
varReturn = SysCmd(acSysCmdSetStatus, ” “)
If the progress meter is already displayed when you set the text by calling the SysCmd method with the acSysCmdSetStatus action argument, the SysCmd method automatically removes the meter.

Call the SysCmd method with other actions to determine system information about Microsoft Access, including which version number of Microsoft Access is running, whether it is a run-time version, the location of the Microsoft Access executable file, the setting for the /profile argument specified in the command line, and the name of an .ini file associated with Microsoft Access.

Note Both general and customized settings for Microsoft Access are now stored in the Windows Registry, so you probably won’t need an .ini file with your Microsoft Access application. The acSysCmdIniFile action argument exists for compatibility with earlier versions of Microsoft Access.

Call the SysCmd method with the acSysCmdGetObjectState action argument and the objecttype and objectname arguments to return the state of a specified database object. An object can be in one of four possible states: not open or nonexistent, open, new, or changed but not saved.

For example, if you are designing a wizard that inserts a new field in a table, you need to determine whether the structure of the table has been changed but not yet saved, so that you can save it before modifying its structure. You can check the value returned by the SysCmd method to determine the state of the table.

The SysCmd method with the acSysCmdGetObjectState action argument can return any combination of the following constants.

Constant State of database object Value
acObjStateOpen Open 1
acObjStateDirty Changed but not saved 2
acObjStateNew New 4

Note If the object referred to by the objectname argument is either not open or doesn’t exist, the SysCmd method returns a value of zero.

The following code can be used to enable the use of your ActiveX control in expressions when the ActiveX control has been added to a form:

SysCmd 14, “”
Note Replace with the globally unique identifier (GUID) that identifies the ActiveX control that you want to enable in expressions.

Note You cannot remove an ActiveX control once it has been added to the list of allowed controls.

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