HActivateFilter (Function)

Enables the filter that was previously created for the specified data file (view or query). This filter was created by HFilter and disabled by HDeactivateFilter. HActivateFilter has no effect if no filter was declared.

This function can be used with the data files, HFSQL views or queries.

Versions 15 and later

This function is now available for Android applications.

New in version 15

This function is now available for Android applications.

Versions 17 and later

This function is now available for iPhone/iPad applications.

New in version 17

This function is now available for iPhone/iPad applications.

Versions 18 and later

This function is now available in Android Widget mode.

This function is now available in Windows Store apps mode.

New in version 18

This function is now available in Android Widget mode.

This function is now available in Windows Store apps mode.

This function is now available in Android Widget mode.

This function is now available in Windows Store apps mode.

Versions 21 and later

This function is now available in Universal Windows 10 App mode.

New in version 21

This function is now available in Universal Windows 10 App mode.

Note: From version 19, HFSQL is the new name of HyperFileSQL.

Example

// Declare the filter: selecting the customers
// who are between 20 and 60 years old
HFilter(CUSTOMER, AGE_Customer, 20, 60)
...
HDeactivateFilter(CUSTOMER) // Disabled filter
...
// Browse the file with a filter on the age
// Process the customers who are between 20 and 60 years old
// (ProcessCustomer2060 procedure)
HActivateFilter(CUSTOMER)
HReadFirst(CUSTOMER, AGE_Customer)
WHILE HFound(CUSTOMER) = True
ProcessCustomer2060()
HReadNext(CUSTOMER, AGE_Customer)
END

Syntax

<Result> = HActivateFilter([<File name>])

<Result>: Boolean

True if the filter is enabled,
False if an error occurred (file or item not found).

<File name>: Optional character string (with or without quotes)

Name of data file, HFSQL view or query used.

Remarks

Enabling and disabling a filter

The filter is enabled once it has been declared (HFilter). The filter can be disabled by HDeactivateFilter.

Number of possible active filters

A single filter can be enabled at a time for a specific data file.

Operating mode in OLE DB

If HActivateFilter is used when browsing a data file, the browse is stopped. To take the filter into account, the browse must be reinitialized with HReadFirst/HFirst or HReadLast/HLast.

The current position and all the stored positions are lost. The position will be restored according to the value of best item.

Component : wd240hf.dll