Fast Excel .xll Add-In

2023-11-20 00:34 UTC text-davinci-002-render-sha Open in ChatGPT ↗

To create a C++ .xll add-in that updates a range of cells with dummy values as fast as possible in Microsoft Excel, you can use the Excel C API provided by Microsoft. Here’s a basic example of how you might approach this:

#include <xlcall.h>

// Function to update a range of cells with dummy values
int WINAPI UpdateRange(double* result, int rows, int columns)
{
    for (int i = 0; i < rows; ++i) {
        for (int j = 0; j < columns; ++j) {
            result[i * columns + j] = 42.0; // Update with your dummy value
        }
    }
    return 1; // Success
}

// Entry point for the add-in
__declspec(dllexport) int WINAPI xlAutoOpen(void)
{
    // Register the UDF (User Defined Function) with Excel
    Excel12f(xlfRegister, 0, 1, &xDll,
        TempStr12(L"UpdateRange"), TempStr12(L"P", L"B"), TempStr12(L"UpdateRange"), TempStr12(L"Dummy Value"), TempStr12(L"", L""), TempStr12(L"", L""), TempStr12(L""));

    return 1; // Success
}

In this code:

UpdateRange is a function that takes the number of rows and columns in the range and updates each cell with a dummy value (in this case, 42.0).
xlAutoOpen is the entry point for the add-in, where we register the UpdateRange function with Excel using the Excel12f function.
You’ll need to link your project with the appropriate Excel C API libraries and headers.
You can then load the add-in in Excel, and you should be able to use the UpdateRange function in your worksheets.

This is a basic example, and you may need to adapt it to your specific needs and Excel version. Additionally, performance optimization might require more advanced techniques, such as multi-threading or using more specialized Excel APIs.

If you want to create a C++ function that can be called from VBA (Visual Basic for Applications) in Excel, you can create a DLL (Dynamic Link Library) that exports the C++ function and then use VBA to call that function. Here’s a high-level overview of the steps:

Create a C++ DLL:
- Write your C++ function with the desired functionality (e.g., updating a range of cells).
- Build the C++ code into a DLL.

Export the C++ Function:

Use the __declspec(dllexport) modifier to export your C++ function. For example:

extern "C" __declspec(dllexport) void UpdateRange(double* rangeData, int numRows, int numCols)
{
    // Your code to update the Excel range here
}

Use VBA to Call the C++ Function:
- In Excel, open the VBA editor (usually Alt + F11).
- In VBA, create a macro that declares and calls the C++ function from the DLL. You can use the Declare statement to import the function, and then call it like any other VBA function.

Here’s an example of how you might declare and call the C++ function from VBA:

Declare Sub UpdateRange Lib "YourDLLName.dll" (ByRef rangeData As Double, ByVal numRows As Long, ByVal numCols As Long)

Sub CallUpdateRange()
    Dim data() As Double
    Dim numRows As Long
    Dim numCols As Long

    ' Define the data and dimensions
    numRows = 5
    numCols = 3
    ReDim data(1 To numRows * numCols)

    ' Call the C++ function
    UpdateRange data(1), numRows, numCols

    ' Now, 'data' contains the updated values
    ' You can manipulate the data as needed in VBA
End Sub

Make sure to replace "YourDLLName.dll" with the actual name of your DLL file.

This approach allows you to create a C++ function that can be called from VBA without the need to load it as a plugin or add-in in Excel. You can then use VBA to manage the data and interact with Excel as necessary.

If you want to create an XLL (Excel Add-In) using C++ and the Excel SDK, but you still intend to call it from VBA, you can create a custom XLL function and then use VBA to call that function. Here’s a high-level overview of the steps:

Create an XLL Add-In:
- Write your C++ code using the Excel SDK to create a custom XLL function with the desired functionality (e.g., updating a range of cells).
- Build the C++ code into an XLL file.
Use VBA to Call the Custom XLL Function:
- In Excel, open the VBA editor (usually Alt + F11).
- In VBA, create a macro that calls the custom XLL function. You can use the Application.Run method to call the XLL function.

Here’s an example of how you might call the custom XLL function from VBA:

Sub CallCustomXLLFunction()
    Dim result As Variant

    ' Call the custom XLL function using Application.Run
    result = Application.Run("YourXLLFunctionName", arg1, arg2, ...) ' Replace with appropriate arguments

    ' 'result' contains the return value from the custom XLL function
    ' You can manipulate the result as needed in VBA
End Sub

Replace "YourXLLFunctionName" with the name of your custom XLL function and provide the necessary arguments.

This approach allows you to create a custom XLL function using the Excel SDK and call it from VBA without the need to load it as a plugin or add-in in Excel. You can then use VBA to manage the data and interact with Excel as necessary.

If you want to update cells in Excel using the Excel C API and the xlSet command, you can follow these steps in your C++ XLL add-in:

Include the necessary headers:

#include <xlcall.h>
#include <framewrk.h>

Define your custom function that uses xlSet to update cells. Here’s an example:

// Define your custom function
int WINAPI UpdateRangeWithXlSet()
{
    LPXLOPERX cellValue = nullptr;
    int numRows = 5; // Change this to the desired number of rows
    int numCols = 3; // Change this to the desired number of columns

    for (int i = 1; i <= numRows; ++i) {
        for (int j = 1; j <= numCols; ++j) {
            cellValue = TempNumX(42.0); // Replace with your dummy value
            xlSet(&cellValue, TempInt(i), TempInt(j)); // Update the cell
            Excel12f(xlFree, nullptr, 1, cellValue); // Free memory
        }
    }

    return 1; // Success
}

In your entry point function (e.g., xlAutoOpen), register the custom function:

__declspec(dllexport) int WINAPI xlAutoOpen(void)
{
    // Register the custom function with Excel
    Excel12f(xlfRegister, 0, 1, &xDll,
        TempStr12(L"UpdateRangeWithXlSet"), TempStr12(L"P", L"B"), TempStr12(L"UpdateRangeWithXlSet"), TempStr12(L"Dummy Value"), TempStr12(L"", L""), TempStr12(L"", L""), TempStr12(L""));

    return 1; // Success
}

Build your XLL add-in and load it into Excel.
In Excel, you can call your custom function UpdateRangeWithXlSet from a cell or a VBA macro:

=UpdateRangeWithXlSet()

This will invoke your custom function, which uses xlSet to update the cells with the dummy values.

Please adjust the number of rows, columns, and the dummy value as needed for your specific use case.

If you want to push an array of values directly to Excel worksheet cells without using a loop and leveraging the xlSet command, you can use the following approach:

#include <xlcall.h>

// Define your custom function to push an array to Excel
int WINAPI PushArrayToExcel()
{
    int numRows = 5; // Change this to the desired number of rows
    int numCols = 3; // Change this to the desired number of columns
    double* data = new double[numRows * numCols];

    // Populate the 'data' array with your values (e.g., dummy values)
    for (int i = 0; i < numRows * numCols; ++i) {
        data[i] = 42.0; // Replace with your dummy value
    }

    LPXLOPERX arrayOper = TempArray(numRows, numCols);
    arrayOper->xltype = xltypeMulti | xlbitDLLFree;

    for (int i = 0; i < numRows * numCols; ++i) {
        arrayOper->val.array.lparray[i] = TempNumX(data[i]);
    }

    // Set the array to a range of cells using xlSet
    xlSet(arrayOper, TempStr12(L"Sheet1"), TempStr12(L"A1"));

    delete[] data; // Free memory

    return 1; // Success
}

In this code:

We create a dynamic array data to store the values you want to push to Excel.
We populate the data array with the desired values (in this case, dummy values).
We create an LPXLOPERX (Excel OPER structure) to hold the array data. We set its xltype to indicate that it’s a multi-cell array.
We fill the arrayOper with the values from the data array.
Finally, we use xlSet to set the array to a range of cells, starting from cell A1 on Sheet1.

Make sure to adjust the numRows, numCols, and the data array with your specific data. This way, you can efficiently push an array of values to Excel cells without the need for explicit loops.

To pass a pointer to a worksheet from VBA to your XLL add-in written in C++, you’ll need to follow a specific procedure. You cannot directly pass a pointer to a worksheet, but you can pass a reference to the worksheet’s name or other identifying information, allowing your C++ XLL function to work with that specific worksheet. Here’s a step-by-step guide:

In VBA, define a function that calls your C++ XLL function and passes the worksheet reference.

Public Declare Function YourXLLFunction Lib "YourXLLFileName.dll" (ByVal worksheetName As String) As Long

Sub CallXLLFunctionWithWorksheetPointer()
    Dim worksheetName As String
    worksheetName = ActiveSheet.Name ' Replace this with the worksheet you want to reference

    Dim result As Long
    result = YourXLLFunction(worksheetName)

    ' Process the result if needed
End Sub

In this code, we declare a function YourXLLFunction from your XLL DLL and pass the worksheet name as a string parameter.

In your C++ XLL add-in code, implement the function that receives the worksheet reference (worksheet name).

#include <xlcall.h>

// Define your custom XLL function that takes a worksheet reference
int WINAPI YourXLLFunction(const char* worksheetName)
{
    // Use 'worksheetName' to identify the worksheet you want to work with

    // Example: Activate the worksheet
    int result = Excel12f(xlSheetActivate, 0, 1, TempStr12(worksheetName), TempInt(1));

    // Process the worksheet as needed

    return 1; // Success
}

In this code, we receive the worksheet name as a parameter and use it to identify and work with the desired worksheet, such as activating it. You can modify this function to perform any specific actions you need on the identified worksheet.

Build your XLL DLL and ensure it’s loaded in Excel.
Run the VBA macro CallXLLFunctionWithWorksheetPointer to call your XLL function and pass the worksheet reference.

Remember to replace "YourXLLFileName.dll" with the actual filename of your XLL DLL, and modify the function to perform the desired actions on the identified worksheet. This way, you can effectively pass a reference to a worksheet from VBA to your C++ XLL add-in.