How to copy contents of Excel UsedRange into an array for faster reading?

问题

I'm trying to improve the performance of an application that is reading cells from an Excel worksheet row by row. I found this solution

https://stackoverflow.com/a/25842904/1462656

You want to do it in one operation:

object[,] objectArray = cSheet.get_Range("A1:C4").Value2; 
dataRange.Value2 = objectArray;

Is it assuming all the cells are of type Value2?.

In general I would like to know how to get the contents of the UsedRange into a local array for faster access (instead of keep going back and forth through the interop). But I don't know in advance the size, but I know in advance the cell types on each column. They are a combination of Value2 and Formula.

My code so far

        Application application = new Application();
        application.Workbooks.Open(file);
        Workbook workbook = application.Workbooks.get_Item(1);
        Worksheet worksheet = workbook.Worksheets.get_Item(1);

        Range UsedRange = worksheet.UsedRange;
        int rows = UsedRange.Rows.Count;
        int cols = UsedRange.Columns.Count;

        object[,] objectArray = new object[rows,cols];

I don't know what to do next.

I was going to do this

objectArray = (object[,])UsedRange.Range[?,?];

But I don't know the syntax to specify the Range using the columns count and rows count I found above.

Originally I had a for loop like this which was extremely slow

for (int rowIndex = 2; rowIndex < UsedRange.Rows.Count; rowIndex++){

    string str1= UsedRange.Rows.Cells[rowIndex, 0 + 1].Value2.ToString();
    string str2= UsedRange.Rows.Cells[rowIndex, 1 + 1].Formula as string;

}

回答1:

The whole point is to do the Excel operation in one step and then use the .Net object[,]. Eg:

object[,] objectArray = new object[rows,cols];

I don't know what to do next.

object[,] objectArray = shtName.get_Range("A1:Z100").Value2;

for (int row = 0; row < objectArray.GetLength(0); row++)
{
    for (int col = 0; col < objectArray.GetLength(1); col++)
    {
        Debug.WriteLine(objectArray[row,col].ToString());
    }
}

_{ps I haven't tested this, very busy today}

Each time you call Excel there is an underlying RPC call that gets marshalled.

This will help as well: https://stackoverflow.com/a/13983731/495455

回答2:

I could not specify the range as cell values as in the other solutions for example

shtName.get_Range("A1:Z100")

So what I was missing was a way to specify the used range without entering cell range as above, and I found the answer from this example

https://www.dotnetperls.com/excel-vbnet

        Range UsedRange = worksheet.UsedRange;

        object[,] objectArray = (object[,])UsedRange.Value[XlRangeValueDataType.xlRangeValueDefault];

        for (int row = 2; row < objectArray.GetUpperBound(0); row++)
        {
             string str1= (objectArray[row, 1] == null) ? string.Empty : objectArray[row, 1].ToString();

             string str2= (objectArray[row, 2] == null) ? string.Empty : objectArray[row, 2].ToString();

             //...etc
        }

来源：https://stackoverflow.com/questions/49784560/how-to-copy-contents-of-excel-usedrange-into-an-array-for-faster-reading

标签

excel

office-interop

excel-interop