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使用NPOI导入导出标准Excel

2024-07-26 08:25:47   222人阅读

 

使用NPOI导出

从DataTable读取内容来创建Workbook对象：

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public static MemoryStream RenderToExcel(DataTable table)
{
    MemoryStream ms = new MemoryStream();
 
    using (table)
    {
        using (IWorkbook workbook = new HSSFWorkbook())
        {
            using (ISheet sheet = workbook.CreateSheet())
            {
                IRow headerRow = sheet.CreateRow(0);
 
                // handling header.
                foreach (DataColumn column in table.Columns)
                    headerRow.CreateCell(column.Ordinal).SetCellValue(column.Caption);//If Caption not set, returns the ColumnName value
 
                // handling value.
                int rowIndex = 1;
 
                foreach (DataRow row in table.Rows)
                {
                    IRow dataRow = sheet.CreateRow(rowIndex);
 
                    foreach (DataColumn column in table.Columns)
                    {
                        dataRow.CreateCell(column.Ordinal).SetCellValue(row[column].ToString());
                    }
 
                    rowIndex++;
                }
 
                workbook.Write(ms);
                ms.Flush();
                ms.Position = 0;
            }
        }
    }
    return ms;
}

如果看不惯DataTable，那么DataReader也行：

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public static MemoryStream RenderToExcel(IDataReader reader)
{
    MemoryStream ms = new MemoryStream();
 
    using (reader)
    {
        using (IWorkbook workbook = new HSSFWorkbook())
        {
            using (ISheet sheet = workbook.CreateSheet())
            {
                IRow headerRow = sheet.CreateRow(0);
                int cellCount = reader.FieldCount;
 
                // handling header.
                for (int i = 0; i < cellCount; i++)
                {
                    headerRow.CreateCell(i).SetCellValue(reader.GetName(i));
                }
 
                // handling value.
                int rowIndex = 1;
                while (reader.Read())
                {
                    IRow dataRow = sheet.CreateRow(rowIndex);
 
                    for (int i = 0; i < cellCount; i++)
                    {
                        dataRow.CreateCell(i).SetCellValue(reader[i].ToString());
                    }
 
                    rowIndex++;
                }
 
                workbook.Write(ms);
                ms.Flush();
                ms.Position = 0;
            }
        }
    }
    return ms;
}

以上代码把创建的Workbook对象保存到流中，可以通过以下方法输出到浏览器，或是保存到硬盘中：

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static void SaveToFile(MemoryStream ms, string fileName)
{
    using (FileStream fs = new FileStream(fileName, FileMode.Create, FileAccess.Write))
    {
        byte[] data = http://www.mamicode.com/ms.ToArray();
 
        fs.Write(data, 0, data.Length);
        fs.Flush();
 
        data = http://www.mamicode.com/null;
    }
}
 
static void RenderToBrowser(MemoryStream ms, HttpContext context, string fileName)
{
    if (context.Request.Browser.Browser == "IE")
        fileName = HttpUtility.UrlEncode(fileName);
    context.Response.AddHeader("Content-Disposition", "attachment;fileName=" + fileName);
    context.Response.BinaryWrite(ms.ToArray());
}

 

使用NPOI导入

需要注意的是，sheet.LastRowNum = sheet.PhysicalNumberOfRows - 1，这里可能存在BUG：当没有数据或只有一行数据时sheet.LastRowNum为0，PhysicalNumberOfRows 表现正常。

这里读取流中的Excel来创建Workbook对象，并转换成DataTable：

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static DataTable RenderFromExcel(Stream excelFileStream)
{
    using (excelFileStream)
    {
        using (IWorkbook workbook = new HSSFWorkbook(excelFileStream))
        {
            using (ISheet sheet = workbook.GetSheetAt(0))//取第一个表
            {
                DataTable table = new DataTable();
 
                IRow headerRow = sheet.GetRow(0);//第一行为标题行
                int cellCount = headerRow.LastCellNum;//LastCellNum = PhysicalNumberOfCells
                int rowCount = sheet.LastRowNum;//LastRowNum = PhysicalNumberOfRows - 1
 
                //handling header.
                for (int i = headerRow.FirstCellNum; i < cellCount; i++)
                {
                    DataColumn column = new DataColumn(headerRow.GetCell(i).StringCellValue);
                    table.Columns.Add(column);
                }
 
                for (int i = (sheet.FirstRowNum + 1); i <= rowCount; i++)
                {
                    IRow row = sheet.GetRow(i);
                    DataRow dataRow = table.NewRow();
 
                    if (row != null)
                    {
                        for (int j = row.FirstCellNum; j < cellCount; j++)
                        {
                            if (row.GetCell(j) != null)
                                dataRow[j] = GetCellValue(row.GetCell(j));
                        }
                    }
 
                    table.Rows.Add(dataRow);
                }
                return table;
 
            }
        }
    }
}

或者是直接生成SQL语句来插入到数据库：

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public static int RenderToDb(Stream excelFileStream, string insertSql, DBAction dbAction)
{
    int rowAffected = 0;
    using (excelFileStream)
    {
        using (IWorkbook workbook = new HSSFWorkbook(excelFileStream))
        {
            using (ISheet sheet = workbook.GetSheetAt(0))//取第一个工作表
            {
                StringBuilder builder = new StringBuilder();
 
                IRow headerRow = sheet.GetRow(0);//第一行为标题行
                int cellCount = headerRow.LastCellNum;//LastCellNum = PhysicalNumberOfCells
                int rowCount = sheet.LastRowNum;//LastRowNum = PhysicalNumberOfRows - 1
 
                for (int i = (sheet.FirstRowNum + 1); i <= rowCount; i++)
                {
                    IRow row = sheet.GetRow(i);
                    if (row != null)
                    {
                        builder.Append(insertSql);
                        builder.Append(" values (");
                        for (int j = row.FirstCellNum; j < cellCount; j++)
                        {
                            builder.AppendFormat("‘{0}‘,", GetCellValue(row.GetCell(j)).Replace("‘", "‘‘"));
                        }
                        builder.Length = builder.Length - 1;
                        builder.Append(");");
                    }
 
                    if ((i % 50 == 0 || i == rowCount) && builder.Length > 0)
                    {
                        //每50条记录一次批量插入到数据库
                        rowAffected += dbAction(builder.ToString());
                        builder.Length = 0;
                    }
                }
            }
        }
    }
    return rowAffected;
}

这里的Excel可能没有数据，所以可以加一个方法来检测：

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public static bool HasData(Stream excelFileStream)
{
    using (excelFileStream)
    {
        using (IWorkbook workbook = new HSSFWorkbook(excelFileStream))
        {
            if (workbook.NumberOfSheets > 0)
            {
                using (ISheet sheet = workbook.GetSheetAt(0))
                {
                    return sheet.PhysicalNumberOfRows > 0;
                }
            }
        }
    }
    return false;
}

 转自http://www.cnblogs.com/lwme/archive/2011/11/18/npoi_excel_import_export.html

使用NPOI导入导出标准Excel


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