C# 读取Excel到DataTable两种方式对比

方式一 OLEDB读取 数据库引擎

优点：读取速度快，依据sheet排序读取

缺点：对于Excel版本依赖强，无法读取指定sheet

错误提示：本地计算机未指定 Microsoft.ACE.OLEDB.12.0

解决方法：win7(64位)+office 2010(64位) 更改目标平台为X86

win10(64位)+office 2010(64位) 更改目标平台无效，下载安装AccessDatabaseEngine.exe，重启无效，项目需求采用方式二

注：2019年7月20日之前和平台无关，均可使用（可能office服务被禁，公司特殊），情况紧急，采用方式二。

代码如下：

public static List<DataTable> excelToDataTable(string filePath)
        {
            List<DataTable> dtList = new List<DataTable>();
            string connStr = "";
            string fileType = System.IO.Path.GetExtension(filePath);
            if (string.IsNullOrEmpty(fileType)) return null;
            if (fileType == ".xls")
                connStr = "Provider=Microsoft.Jet.OLEDB.4.0;" + "Data Source=" + filePath + ";" + ";Extended Properties=\"Excel 8.0;HDR=YES;IMEX=1\"";
            else
                connStr = "Provider=Microsoft.ACE.OLEDB.12.0;" + "Data Source=" + filePath + ";" + ";Extended Properties=\"Excel 12.0;HDR=N0;IMEX=1\"";
            string sql_F = "Select * FROM [{0}]";
            OleDbConnection conn = null;
            OleDbDataAdapter da = null;
            DataTable dtSheetName = null;
            DataSet ds = new DataSet();
            DataTable dtNew = new DataTable();
            try
            {
                // 初始化连接，并打开    
                conn = new OleDbConnection(connStr);
                conn.Open();
                // 获取数据源的表定义元数据 
                string SheetName = "";
                dtSheetName = conn.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, new object[] { null, null, null, "TABLE" });
                // 初始化适配器           
                da = new OleDbDataAdapter();
          
                for (int i = 0; i < dtSheetName.Rows.Count; i++)
                {
                    DataTable dt = new DataTable();
                    SheetName = (string)dtSheetName.Rows[i]["TABLE_NAME"];
                    if (SheetName.Contains("$") && !SheetName.Replace("'", "").EndsWith("$"))
                    {
                        continue;
                    }
                    da.SelectCommand = new OleDbCommand(String.Format(sql_F, SheetName), conn);
                    dt.TableName = i.ToString();
                    da.Fill(dt);
                    dtList.Add(dt);     
                }
            }
            catch (Exception ex)
            {
                //MessageBox.Show(ex.ToString());
            }
            finally
            {
                // 关闭连接             
                if (conn.State == ConnectionState.Open)
                {
                    conn.Close();
                    da.Dispose();
                    conn.Dispose();
                }
            }
            return dtList;
        }

方式二 Excel引擎读取 Microsoft.Office.Interop.Excel

使用方式：引用 Microsoft.Office.Interop.Excel 调用Excel读取

优点：不受Excel版本限制，可指定sheet读取

缺点：读取速度慢，几千数据10分钟

代码如下：

public static List<DataTable> excelToDataTable(string filePath,bool hasTitle = false)
        {
            List<DataTable> dtList = new List<DataTable>();
            int iRowCount;
            int iColCount;

Microsoft.Office.Interop.Excel.Application app = new Microsoft.Office.Interop.Excel.Application();
            Microsoft.Office.Interop.Excel.Sheets sheets;
            object oMissiong = System.Reflection.Missing.Value;
            Microsoft.Office.Interop.Excel.Workbook workbook = null;
            DataTable dt = new DataTable();

try
            {
                if (app == null) return null;
                workbook = app.Workbooks.Open(filePath, oMissiong, oMissiong, oMissiong, oMissiong, oMissiong,
                    oMissiong, oMissiong, oMissiong, oMissiong, oMissiong, oMissiong, oMissiong, oMissiong, oMissiong);
                sheets = workbook.Worksheets;

//将数据读入到DataTable中
                Microsoft.Office.Interop.Excel.Worksheet worksheet = sheets.get_Item(1);
                if (worksheet == null) return null;
                iRowCount = worksheet.UsedRange.Rows.Count;
                iColCount = worksheet.UsedRange.Columns.Count;
                //生成列头
                for (int i = 0; i < iColCount; i++)
                {
                    var name = "column" + i;
                    if (hasTitle)
                    {
                        var txt = ((Microsoft.Office.Interop.Excel.Range)worksheet.Cells[1, i + 1]).Text.ToString();
                        if (!string.IsNullOrWhiteSpace(txt)) name = txt;
                    }
                    while (dt.Columns.Contains(name)) name = name + "_1";//重复行名称会报错。
                    dt.Columns.Add(new DataColumn(name, typeof(string)));
                }
                //生成行数据
                Microsoft.Office.Interop.Excel.Range range;
                int rowIdx = hasTitle ? 2 : 1;
                for (int iRow = rowIdx; iRow <= iRowCount; iRow++)
                {
                    DataRow dr = dt.NewRow();
                    for (int iCol = 1; iCol <= iColCount; iCol++)
                    {
                        range = (Microsoft.Office.Interop.Excel.Range)worksheet.Cells[iRow, iCol];
                        dr[iCol - 1] = (range.Value2 == null) ? "" : range.Text.ToString();
                    }
                    dt.Rows.Add(dr);
                }
               dtList.Add(dt);
                for (int i = 2; i <= sheets.Count; i++)
                {
                    worksheet=sheets.get_Item(i);//读取第一张表 
                    iRowCount = worksheet.UsedRange.Rows.Count;
                    iColCount = worksheet.UsedRange.Columns.Count;
                    //生成列头
                    for (int j = 0; j < iColCount; j++)
                    {
                        var name = "column" + i;
                        if (hasTitle)
                        {
                            var txt = ((Microsoft.Office.Interop.Excel.Range)worksheet.Cells[1, j + 1]).Text.ToString();
                            if (!string.IsNullOrWhiteSpace(txt)) name = txt;
                        }
                        while (dt.Columns.Contains(name)) name = name + "_1";//重复行名称会报错。
                        dt.Columns.Add(new DataColumn(name, typeof(string)));
                    }
                    //生成行数据
                    Microsoft.Office.Interop.Excel.Range range1;
                    int rowIdx1 = hasTitle ? 2 : 1;
                    for (int iRow = rowIdx1; iRow <= iRowCount; iRow++)
                    {
                        DataRow dr = dt.NewRow();
                        for (int iCol = 1; iCol <= iColCount; iCol++)
                        {
                            range1 = (Microsoft.Office.Interop.Excel.Range)worksheet.Cells[iRow, iCol];
                            dr[iCol - 1] = (range1.Value2 == null) ? "" : range1.Text.ToString();
                        }
                        dt.Rows.Add(dr);
                    }
                    dtList.Add(dt);
                }
                return dtList;
            }
            catch { return null; }
            finally
            {
                workbook.Close(false, oMissiong, oMissiong);
                System.Runtime.InteropServices.Marshal.ReleaseComObject(workbook);
                workbook = null;
                app.Workbooks.Close();
                app.Quit();
                System.Runtime.InteropServices.Marshal.ReleaseComObject(app);
                app = null;
            }
        }