導入大型.xlsx文件非常慢

Question

我是C＃和WPF的新手，並嘗試將大型.xlsx文件導入到datagrid中，因此我可以擁有大約200多個列和100,000多個行。 按照我目前的方法，這需要一個多小時（我沒有完成）。 我使用csv格式的格式示例如下：

"Time","Dist","V_Front","V_Rear","RPM"
"s","m","km/h","km/h","rpm"
"0.000","0","30.3","30.0","11995"
"0.005","0","30.3","30.0","11965"
"0.010","0","30.3","31.0","11962"

我目前正在使用Interop，但我想知道是否還有另一種方法可以大大減少加載時間。 我希望使用SciCharts（他們有學生許可證）來繪制這些數據，並帶有用於頻道選擇的復選框，但這是另一回事。

.CS

    private void Button_Click(object sender, RoutedEventArgs e)
    {
        OpenFileDialog openfile = new OpenFileDialog();
        openfile.DefaultExt = ".xlsx";
        openfile.Filter = "(.xlsx)|*.xlsx";

        var browsefile = openfile.ShowDialog();

        if (browsefile == true)
        {
            txtFilePath.Text = openfile.FileName;

            Microsoft.Office.Interop.Excel.Application excelApp = new Microsoft.Office.Interop.Excel.Application();
            Microsoft.Office.Interop.Excel.Workbook excelBook = excelApp.Workbooks.Open(txtFilePath.Text.ToString(), 0, true, 5, "", "", true, Microsoft.Office.Interop.Excel.XlPlatform.xlWindows, "\t", false, false, 0, true, 1, 0);
            Microsoft.Office.Interop.Excel.Worksheet excelSheet = (Microsoft.Office.Interop.Excel.Worksheet)excelBook.Worksheets.get_Item(1); ;
            Microsoft.Office.Interop.Excel.Range excelRange = excelSheet.UsedRange;

            string strCellData = "";
            double douCellData;
            int rowCnt = 0;
            int colCnt = 0;

            DataTable dt = new DataTable();
            for (colCnt = 1; colCnt <= excelRange.Columns.Count; colCnt++)
            {
                string strColumn = "";
                strColumn = (string)(excelRange.Cells[1, colCnt] as Microsoft.Office.Interop.Excel.Range).Value2;
                dt.Columns.Add(strColumn, typeof(string));
            }

            for (rowCnt = 2; rowCnt <= excelRange.Rows.Count; rowCnt++)
            {
                string strData = "";
                for (colCnt = 1; colCnt <= excelRange.Columns.Count; colCnt++)
                {
                    try
                    {
                        strCellData = (string)(excelRange.Cells[rowCnt, colCnt] as Microsoft.Office.Interop.Excel.Range).Value2;
                        strData += strCellData + "|";
                    }
                    catch (Exception ex)
                    {
                        douCellData = (excelRange.Cells[rowCnt, colCnt] as Microsoft.Office.Interop.Excel.Range).Value2;
                        strData += douCellData.ToString() + "|";
                    }
                }
                strData = strData.Remove(strData.Length - 1, 1);
                dt.Rows.Add(strData.Split('|'));
            }

            dtGrid.ItemsSource = dt.DefaultView;

            excelBook.Close(true, null, null);
            excelApp.Quit();


        }
    }

我真的很感激任何幫助。

Answer 1

問題在於單個讀取過多，這會導致大量反射使用和Excel與應用程序之間的編組。 如果您不關心內存使用情況，則可以將整個Range讀取到內存中並從內存中進行操作，而不必單獨讀取單元格。 以下代碼在5列103938行的測試文件上以3880毫秒的速度運行：

OpenFileDialog openfile = new OpenFileDialog();
openfile.DefaultExt = ".xlsx";
openfile.Filter = "(.xlsx)|*.xlsx";

var browsefile = openfile.ShowDialog();

if (browsefile == true)
{
    txtFilePath.Text = openfile.FileName;

    var excelApp = new Microsoft.Office.Interop.Excel.Application();
    var excelBook = excelApp.Workbooks.Open(txtFilePath.Text, 0, true, 5, "", "", true,
        Microsoft.Office.Interop.Excel.XlPlatform.xlWindows, "\t", false, false, 0, true, 1, 0);
    var excelSheet = (Microsoft.Office.Interop.Excel.Worksheet) excelBook.Worksheets.Item[1];

    Microsoft.Office.Interop.Excel.Range excelRange = excelSheet.UsedRange;

    DataTable dt = new DataTable();

    object[,] value = excelRange.Value;

    int columnsCount = value.GetLength(1);
    for (var colCnt = 1; colCnt <= columnsCount; colCnt++)
    {
        dt.Columns.Add((string)value[1, colCnt], typeof(string));
    }

    int rowsCount = value.GetLength(0);
    for (var rowCnt = 2; rowCnt <= rowsCount; rowCnt++)
    {
        var dataRow = dt.NewRow();
        for (var colCnt = 1; colCnt <= columnsCount; colCnt++)
        {
            dataRow[colCnt - 1] = value[rowCnt, colCnt];
        }
        dt.Rows.Add(dataRow);
    }

    dtGrid.ItemsSource = dt.DefaultView;

    excelBook.Close(true);
    excelApp.Quit();
}

如果您不想讀取整個Range ，則應該分批進行。

另一個優化是在后台線程上運行此代碼，因此在加載UI時不會阻塞UI。

編輯

為了在后台線程上運行此代碼，您可以將按鈕單擊處理程序修改為異步方法，然后將解析邏輯放入另一個方法中，該方法使用Task.Run在線程Task.Run線程上運行實際解析：

private async void Button_Click(object sender, RoutedEventArgs e)
{
    OpenFileDialog openfile = new OpenFileDialog();
    openfile.DefaultExt = ".xlsx";
    openfile.Filter = "(.xlsx)|*.xlsx";

    var browsefile = openfile.ShowDialog();

    if (browsefile == true)
    {
        txtFilePath.Text = openfile.FileName;

        DataTable dataTable = await ParseExcel(txtFilePath.Text).ConfigureAwait(true);

        dtGrid.ItemsSource = dataTable.DefaultView;
    }
}

private Task<DataTable> ParseExcel(string filePath)
{
    return Task.Run(() =>
    {
        var excelApp = new Microsoft.Office.Interop.Excel.Application();
        var excelBook = excelApp.Workbooks.Open(filePath, 0, true, 5, "", "", true,
            Microsoft.Office.Interop.Excel.XlPlatform.xlWindows, "\t", false, false, 0, true, 1, 0);
        var excelSheet = (Microsoft.Office.Interop.Excel.Worksheet) excelBook.Worksheets.Item[1];

        Microsoft.Office.Interop.Excel.Range excelRange = excelSheet.UsedRange;

        DataTable dt = new DataTable();

        object[,] value = excelRange.Value;

        int columnsCount = value.GetLength(1);
        for (var colCnt = 1; colCnt <= columnsCount; colCnt++)
        {
            dt.Columns.Add((string) value[1, colCnt], typeof(string));
        }

        int rowsCount = value.GetLength(0);
        for (var rowCnt = 2; rowCnt <= rowsCount; rowCnt++)
        {
            var dataRow = dt.NewRow();
            for (var colCnt = 1; colCnt <= columnsCount; colCnt++)
            {
                dataRow[colCnt - 1] = value[rowCnt, colCnt];
            }
            dt.Rows.Add(dataRow);
        }

        excelBook.Close(true);
        excelApp.Quit();

        return dt;
    });
}

處理程序僅調用解析函數，該解析函數在后台線程上運行，完成后，可以通過將結果DataTable分配給ItemsSource來繼續處理程序。