C#如何快速高效地导出大量数据？
本文转载：http://www.cnblogs.com/herbert/archive/2010/07/28/1787095.html
在C#里面如果对应的把datagridview里面的每个cell的数据一个一个地对应的写入到excel，你会发现非常的慢，这个时候，你可以先把datagrid里面的数据放入到一个二维的string数组里面， 然后利用range对象的value赋值，那样会快很多。代码如下
public static void DataGridViewToExcel(DataGridView dgv) { #region Validate the path and file properties SaveFileDialog dlg = new SaveFileDialog(); dlg.DefaultExt = "xlsx "; dlg.Filter = "EXCEL文件(*.XLSX)|*.xlsx "; dlg.InitialDirectory = Environment.GetFolderPath(Environment.SpecialFolder.Desktop); // Open the save file dialog if (dlg.ShowDialog() == DialogResult.Cancel) return; // Get the filename string fileNameString = dlg.FileName; if (fileNameString.Trim() == " ") return; // Define the rows count and columns count int rowscount = dgv.Rows.Count; int colscount = dgv.Columns.Count; if (rowscount <= 0) { MessageBox.Show("No data to save ", "Info", MessageBoxButtons.OK, MessageBoxIcon.Information); return; } if (colscount <= 0) { MessageBox.Show("No data to save ", "Info", MessageBoxButtons.OK, MessageBoxIcon.Information); return; } if (rowscount > 65536) { MessageBox.Show("Too much records(The number of the records exceeds 65536)，CANNOT SAVE! ", "Info", MessageBoxButtons.OK, MessageBoxIcon.Information); return; } if (colscount > 255) { MessageBox.Show("Too much columns, CANNOT SAVE! ", "Info ", MessageBoxButtons.OK, MessageBoxIcon.Information); return; } // Check if the file exisits FileInfo file = new FileInfo(fileNameString); if (file.Exists) { try { file.Delete(); } catch (Exception error) { MessageBox.Show(error.Message, "Cannot delete the file!", MessageBoxButtons.OK, MessageBoxIcon.Warning); return; } } #endregion Microsoft.Office.Interop.Excel.Application objExcel = null; Microsoft.Office.Interop.Excel.Workbook objWorkbook = null; Microsoft.Office.Interop.Excel.Worksheet objsheet = null; object missing = System.Reflection.Missing.Value; try { objExcel = new Microsoft.Office.Interop.Excel.Application(); objWorkbook = objExcel.Workbooks.Add(missing); objsheet = (Microsoft.Office.Interop.Excel.Worksheet)objWorkbook.ActiveSheet; objExcel.Visible = false; int rowCount = dgv.RowCount; int columnCount = dgv.ColumnCount; string[,] datas = new string[rowCount + 1, columnCount]; for (int i = 0; i < columnCount; i++) { if (dgv.Columns[i].Visible == true) { datas[0, i] = dgv.Columns[i].HeaderText.Trim(); } } for (int row = 0; row < rowCount; row++) { for (int col = 0; col < columnCount; col++) { if (dgv.Columns[col].Visible == true) { try { datas[row + 1, col] = dgv.Rows[row].Cells[col].Value.ToString().Trim(); } catch (Exception ex) { MessageBox.Show("An exception occured:" + ex.Message, "Information", MessageBoxButtons.OK, MessageBoxIcon.Information); } } } } int exportRowCount = rowCount + 1; Range range = objsheet.get_Range("A1", "C" + exportRowCount); range.Value2 = datas; objsheet.Columns.EntireColumn.AutoFit(); // Automatically change the column width objWorkbook.SaveAs(fileNameString, missing, missing, missing, missing, missing, Microsoft.Office.Interop.Excel.XlSaveAsAccessMode.xlShared, missing, missing, missing, missing, missing); } catch (Exception error) { MessageBox.Show(error.Message, "Warning ", MessageBoxButtons.OK, MessageBoxIcon.Warning); return; } finally { if (objWorkbook != null) objWorkbook.Close(missing, missing, missing); if (objExcel.Workbooks != null) objExcel.Workbooks.Close(); if (objExcel != null) objExcel.Quit(); objsheet = null; objWorkbook = null; objExcel = null; } MessageBox.Show(fileNameString + "\n\n Export finished! ", "Info ", MessageBoxButtons.OK, MessageBoxIcon.Information); }
前面有一段代码是check 数据的，其实可以根据自己情况再制定。主要是导入的那几句话。这里要注意一个问题了，就是在visual studio里面
Worksheet.get_Range Method
Range get_Range(
Object Cell1,
Object Cell2
)
这个要注意了，在visual studio 2010以前都可以这样用，但是visual studio 2010里面是下面的形式
Range get_Range(object Cell1, object Cell2 = Type.Missing);
所以这里选定一个范围的cell需要这样写
Range range = objsheet.get_Range("A1", "C" + exportRowCount);
参考文章地址：这里的这个示例给出的是一个可以导出大于60000行数据的代码，就是可以分成多个worksheet
http://www.cnblogs.com/Ihaveadream/archive/2009/01/04/1368525.html
string saveFileName = ""; bool fileSaved = false; SaveFileDialog saveDialog = new SaveFileDialog(); saveDialog.DefaultExt = "xls"; saveDialog.Filter = "Excel文件|*.xls"; saveDialog.FileName = "Sheet1"; saveDialog.ShowDialog(); saveFileName = saveDialog.FileName; if (saveFileName.IndexOf(":") < 0) return; //被点了取消 ExcelApp xlApp = new ExcelApp(); if (xlApp == null) { strMessage = "无法创建Excel对象，可能您的计算机上未安装Excel软件。"; MessageBox.Show("无法创建Excel对象，可能您的计算机上未安装Excel软件。"); return; } Workbooks workbooks = xlApp.Workbooks; Workbook workbook = workbooks.Add(XlWBATemplate.xlWBATWorksheet); Worksheet worksheet = (Worksheet)workbook.Worksheets[1];//取得sheet1 //写入字段 for (int i = 0; i < gridview.Columns.View.VisibleColumns.Count; i++) { worksheet.Cells[1, i + 1] = gridview.GetVisibleColumn(i).Caption; } //写入数值 int r; for (r = 0; r < table.Rows.Count; r++ ) { for (int i = 0; i < gridview.Columns.View.VisibleColumns.Count; i++) { if (gridview.GetVisibleColumn(i).ColumnType == typeof(string) || gridview.GetVisibleColumn(i).ColumnType == typeof(Decimal) || gridview.GetVisibleColumn(i).ColumnType == typeof(DateTime)) { worksheet.Cells[r + 2, i + 1] = gridview.GetRowCellDisplayText(r, gridview.GetVisibleColumn(i));//dt.Rows[r][i]; object obj = table.Rows[r][gridview.GetVisibleColumn(i).FieldName]; worksheet.Cells[r + 2, i + 1] = obj == null ? "": "'"+obj.ToString(); } } System.Windows.Forms.Application.DoEvents(); } if (saveFileName != "") { try { workbook.Saved = true; workbook.SaveCopyAs(saveFileName); fileSaved = true; } catch (Exception ex) { strMessage = "导出文件时出错,文件可能正被打开"; fileSaved = false; MessageBox.Show("导出文件时出错,文件可能正被打开！"n" + ex.Message); } } else { fileSaved = false; } xlApp.Quit(); GC.Collect();//强行销毁 if (fileSaved && System.IO.File.Exists(saveFileName)) System.Diagnostics.Process.Start(saveFileName); //打开EXCEL
上导出的代码在网上铺天盖地了已经，它仅适合导出那些最多几百几千的数据量，当使用上述代码导出10万甚至20多万的海量数据时，至少几个小时甚至导出失败。。。。
经过几天的研究，本人发现上述导出的核心代码存在问题，导致速度缓慢，下边看看我修改后的程序：
string saveFileName = ""; bool fileSaved = false; SaveFileDialog saveDialog = new SaveFileDialog(); saveDialog.DefaultExt = "xls"; saveDialog.Filter = "Excel文件|*.xls"; saveDialog.FileName = "Sheet1"; saveDialog.ShowDialog(); saveFileName = saveDialog.FileName; if (saveFileName.IndexOf(":") < 0) return; //被点了取消 ExcelApp xlApp = new ExcelApp(); if (xlApp == null) { strMessage = "无法创建Excel对象，可能您的计算机上未安装Excel软件。"; MessageBox.Show("无法创建Excel对象，可能您的计算机上未安装Excel软件。"); return; } Workbooks workbooks = xlApp.Workbooks; Workbook workbook = workbooks.Add(XlWBATemplate.xlWBATWorksheet); Worksheet worksheet = (Worksheet)workbook.Worksheets[1];//取得sheet1 long rows = table.Rows.Count; /*下边注释的两行代码当数据行数超过行时，出现异常：异常来自HRESULT:0x800A03EC。因为：Excel 2003每个sheet只支持最大行数据 //Range fchR = worksheet.get_Range(worksheet.Cells[1, 1], worksheet.Cells[table.Rows.Count+2, gridview.Columns.View.VisibleColumns.Count+1]); //fchR.Value2 = datas;*/ if (rows > 65535) { long pageRows = 60000;//定义每页显示的行数,行数必须小于 int scount = (int)(rows / pageRows); if (scount * pageRows < table.Rows.Count)//当总行数不被pageRows整除时，经过四舍五入可能页数不准 { scount = scount + 1; } for (int sc = 1; sc <= scount; sc++) { if (sc > 1) { object missing = System.Reflection.Missing.Value; worksheet = (Excel.Worksheet)workbook.Worksheets.Add( missing, missing, missing, missing);//添加一个sheet } else { worksheet = (Worksheet)workbook.Worksheets[sc];//取得sheet1 } string[,] datas = new string[pageRows + 1, gridview.Columns.View.VisibleColumns.Count + 1]; for (int i = 0; i < gridview.Columns.View.VisibleColumns.Count; i++) //写入字段 { datas[0, i] = gridview.GetVisibleColumn(i).Caption; } Range range = worksheet.get_Range(worksheet.Cells[1, 1], worksheet.Cells[1, gridview.Columns.View.VisibleColumns.Count]); range.Interior.ColorIndex = 15;//15代表灰色 range.Font.Bold = true; range.Font.Size = 9; int init = int.Parse(((sc - 1) * pageRows).ToString()); int r = 0; int index = 0; int result; if (pageRows * sc >= table.Rows.Count) { result = table.Rows.Count; } else { result = int.Parse((pageRows * sc).ToString()); } for (r = init; r < result; r++) { index = index + 1; for (int i = 0; i < gridview.Columns.View.VisibleColumns.Count; i++) { if (gridview.GetVisibleColumn(i).ColumnType == typeof(string) || gridview.GetVisibleColumn(i).ColumnType == typeof(Decimal) || gridview.GetVisibleColumn(i).ColumnType == typeof(DateTime)) { object obj = table.Rows[r][gridview.GetVisibleColumn(i).FieldName]; datas[index, i] = obj == null ? "" : "'" + obj.ToString().Trim();//在obj.ToString()前加单引号是为了防止自动转化格式 } } System.Windows.Forms.Application.DoEvents(); } Range fchR = worksheet.get_Range(worksheet.Cells[1, 1], worksheet.Cells[index + 2, gridview.Columns.View.VisibleColumns.Count + 1]); fchR.Value2 = datas; worksheet.Columns.EntireColumn.AutoFit();//列宽自适应。 range = worksheet.get_Range(worksheet.Cells[1, 1], worksheet.Cells[index + 1, gridview.Columns.View.VisibleColumns.Count]); //15代表灰色 range.Font.Size = 9; range.RowHeight = 14.25; range.Borders.LineStyle = 1; range.HorizontalAlignment = 1; } } else { string[,] datas = new string[table.Rows.Count + 2, gridview.Columns.View.VisibleColumns.Count + 1]; for (int i = 0; i < gridview.Columns.View.VisibleColumns.Count; i++) //写入字段 { datas[0, i] = gridview.GetVisibleColumn(i).Caption; } Range range = worksheet.get_Range(worksheet.Cells[1, 1], worksheet.Cells[1, gridview.Columns.View.VisibleColumns.Count]); range.Interior.ColorIndex = 15;//15代表灰色 range.Font.Bold = true; range.Font.Size = 9; int r = 0; for (r = 0; r < table.Rows.Count; r++) { for (int i = 0; i < gridview.Columns.View.VisibleColumns.Count; i++) { if (gridview.GetVisibleColumn(i).ColumnType == typeof(string) || gridview.GetVisibleColumn(i).ColumnType == typeof(Decimal) || gridview.GetVisibleColumn(i).ColumnType == typeof(DateTime)) { object obj = table.Rows[r][gridview.GetVisibleColumn(i).FieldName]; datas[r + 1, i] = obj == null ? "" : "'" + obj.ToString().Trim();//在obj.ToString()前加单引号是为了防止自动转化格式 } } System.Windows.Forms.Application.DoEvents(); } Range fchR = worksheet.get_Range(worksheet.Cells[1, 1], worksheet.Cells[table.Rows.Count + 2, gridview.Columns.View.VisibleColumns.Count + 1]); fchR.Value2 = datas; worksheet.Columns.EntireColumn.AutoFit();//列宽自适应。 range = worksheet.get_Range(worksheet.Cells[1, 1], worksheet.Cells[table.Rows.Count + 1, gridview.Columns.View.VisibleColumns.Count]); //15代表灰色 range.Font.Size = 9; range.RowHeight = 14.25; range.Borders.LineStyle = 1; range.HorizontalAlignment = 1; } if (saveFileName != "") { try { workbook.Saved = true; workbook.SaveCopyAs(saveFileName); fileSaved = true; } catch (Exception ex) { strMessage = "导出文件时出错,文件可能正被打开"; fileSaved = false; MessageBox.Show("导出文件时出错,文件可能正被打开！"n" + ex.Message); } } else { fileSaved = false; } xlApp.Quit(); GC.Collect();//强行销毁 if (fileSaved && System.IO.File.Exists(saveFileName)) System.Diagnostics.Process.Start(saveFileName); //打开EXCEL
着重看上边蓝色代码的部分，经过前后两种导出方式的对比，您会发现，导出的思想改变了：
原来的程序将数据一个表格一个表格地写入到EXCEL中；修改后的程序先将数据存入二维数组中，然后再将数组值赋予EXCEL应用程序对象的VALUE属性
正是导出思想的改变，使导出速度提高不少，请参考我的导出时间数据对照：
2万条：30分钟-->2分钟左右；3万条：大于60分钟-->3分钟;20万7000多条：导出失败--->15分钟左右
可以明显看出，效率提高了不少吧。
还有一个要提醒大家，EXCEL中SHEET最多存储65535条数据，如果数据过多就需要增加sheet继续存储数据，关于如何使用，上边我修改过的代码中已经有详细的使用，请大家自己去看，这里不再重复。