# Hidden Data in Microsoft Excel Documents

There are several types of hidden data in Microsoft Excel documents, each of which has a corresponding flag in the KV_CONFIG_Arg structure, which you can toggle to determine whether the hidden data is shown.

The following table lists each data type, its default behavior, and its corresponding configuration API flag.

Hidden data settings

Hidden Data Type | Default Behavior | KV_CONFIG_Arg flag
--- | --- | ---
Hidden sheets | Not output | `KV_SS_SHOWHIDDENINFOR`
Formulas | Calculated value | `KV_SS_SHOWFORMULA`
Values and formulas | Calculated value | `KV_SS_SHOWVALUESANDFORMULAS`

To toggle the display of any type of hidden data

1. Define the configurable argument variable to use in the KV_CONFIG_Arg structure. For example:

       KV_CONFIG_Arg setArg = {0}

2. Set the `KV_ALL_OVERWRITECONFIGFILE` flag to overwrite the configuration file settings. For example:

       setArg.keyID = KV_ALLFLAGS;
       setArg.keyType = KV_INT32ARG;
       setArg.keyData.intArg = KV_ALL_OVERWRITECONFIGFILE;

   NOTE: To re-enable configuration file settings later, set `!KV_ALL_OVERWRITECONFIGFILE`.

3. Assign values to the members of the variable. For example:

       setArg.keyID = KV_SSFLAGS;
       setArg.keyType = KV_INT32ARG;
       setArg.keyData.intArg = KV_SS_SHOWHIDDENINFOR;

4. Call fpFilterConfig() with the following arguments to set the variable:

   Argument | Parameter
   --- | ---
   `nType` | `KVFLT_SetConfigurableArguments`
   `nValue` | `TRUE`
   `pData` | The variable defined in step 1.

   For example:

       (*fpFilterConfig)(pKVFilter, KVFLT_SetConfigurableArguments, TRUE, &setArg)

## Example

The following example overwrites the configuration file settings and enables filtering of formulas.

    KV_CONFIG_Arg setArg = {0};

    setArg.keyID = KV_ALLFLAGS;
    setArg.keyType = KV_INT32ARG;
    setArg.keyData.intArg = KV_ALL_OVERWRITECONFIGFILE;

    fpKV_FilterConfig(pFilter, KVFLT_SetConfigurableArguments, TRUE, &setArg);

    setArg.keyID = KV_SSFLAGS;
    setArg.keyType = KV_INT32ARG;
    setArg.keyData.intArg = KV_SS_SHOWFORMULAS;

    fpKV_FilterConfig(pFilter, KVFLT_SetConfigurableArguments, TRUE, &setArg);

## Toggle Hidden Excel Data Settings in the formats.ini File

You can control Microsoft Excel hidden data settings through parameters in the `formats.ini` file.

To toggle hidden Excel data settings in the formats.ini file

1. Open the `formats.ini` file in a text editor.

2. Under `[Options]`, set one or both of the following parameters.

   - To filter text from hidden sheets, set `gethiddeninfo` to `1`. See Filter Hidden Text in Microsoft Excel Files for more information.
   - To filter formulas and formula values, set `getformulastring` to the appropriate value. See Extract Microsoft Excel Formulas for more information.

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