使用dynamicLinq和EPPlus导出到Excel？
作为一个概述，我试图将Export()function添加到我的应用程序 – 允许用户指定某些模型字段，并只通过查询LINQ并使用EPPlus库导出这些字段中的值。 我试图在我的MVC5 / EF代码优先应用程序基于这个例子实现dynamicLINQfunction，但没有多less运气。
using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Mvc; using System.Web.UI; using System.Web.UI.WebControls; using System.IO; using InventoryTracker.DAL; using OfficeOpenXml; using InventoryTracker.Models; using System.Linq.Dynamic; namespace InventoryTracker.Controllers { public class ExportController : Controller { InventoryTrackerContext _db = new InventoryTrackerContext(); public static List<DynamicColumns> DynamicColumnsCollection = new List<DynamicColumns>(); [HttpPost] public ActionResult ExportUsingEPPlus(ExportAssetsViewModel model) { //FileInfo newExcelFile = new FileInfo(output); ExcelPackage package = new ExcelPackage(); var ws = package.Workbook.Worksheets.Add("TestExport"); var exportFields = new List<string>(); foreach(var selectedField in model.SelectedFields) { // Adds selected fields to [exportFields] List<string> exportFields.Add(model.ListOfExportFields.First(s => s.Key == selectedField).Value); } //int cnt = 0; //foreach(var column in exportFields) for (int cnt = 0; cnt < 10; cnt++ ) { DynamicColumnsCollection.Add(new DynamicColumns() { Id = cnt, ip_address = "ip_address" + cnt, mac_address = "mac_address" + cnt, note = "note" + cnt, owner = "owner" + cnt, cost = "cost" + cnt, po_number = "po_number" + cnt, description = "description" + cnt, invoice_number = "invoice_number" + cnt, serial_number = "serial_number" + cnt, asset_tag_number = "asset_tag_number" + cnt, acquired_date = "acquired_date" + cnt, disposed_date = "disposed_date" + cnt, verified_date = "verified_date" + cnt, created_date = "created_date" + cnt, created_by = "created_by" + cnt, modified_date = "modified_date" + cnt, modified_by = "modified_by" + cnt }); } //var selectStatement = DynamicSelectionColumns(exportFields); IQueryable collection = DynamicSelectionColumns(new List<string>() { "id", "owner", "note" }); // Loops to insert column headings into Row 1 of Excel for (int i = 0; i < exportFields.Count(); i++ ) { ws.Cells[1, i + 1].Value = exportFields[i].ToString(); } // Process data from [collectin] into Excel??? ws.Cells["A2"].LoadFromCollection(collection.ToString()); // ws.Cells["A2"].LoadFromCollection(selectStatement.ToString()); var memoryStream = new MemoryStream(); package.SaveAs(memoryStream); string fileName = "Exported-InventoryAssets-" + DateTime.Now + ".xlsx"; string contentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"; memoryStream.Position = 0; return File(memoryStream, contentType, fileName); } public IQueryable DynamicSelectionColumns(List<string> fieldsForExport) { using (var db = new InventoryTrackerContext()) { string fieldIds = "," + "4,5,3,2,6,17,11,12" + ","; //var taskColum = Enum.GetValues(typeof(EnumTasks)).Cast<EnumTasks>().Where(e => fieldIds.Contains("," + ((int)e).ToString() + ",")).Select(e => e.ToString().Replace("_", "")); var taskColum = Enum.GetValues(typeof(EnumTasks)).Cast<EnumTasks>().Where(e => fieldIds.Contains("," + ((int)e).ToString() + ",")).Select(e => e.ToString()); ////string select = "new ( TaskId, " + (taskColum.Count() > 0 ? string.Join(", ", taskColum) + ", " : "") + "Id )"; //string select = "new ( " + string.Join(", ", fieldsForExport) + ")"; ////return db.INV_Assets.ToList().Select(t => new DynamicColumns() { Id = t.Id, TaskId = Project != null ? Project.Alias + "-" + t.Id : t.Id.ToString(), if (!fieldsForExport.Any()) { return null; } string select = string.Format("new ( {0} )", string.Join(", ", fieldsForExport.ToArray())); var collection = DynamicColumnsCollection.Select(t => new DynamicColumns() { Id = t.Id, //Manufacturer = Convert.ToString(t.Manufacturer.manufacturer_description), //Type = t.Type.type_description, //Location = t.Location.location_room, //Vendor = t.Vendor.vendor_name, //Status = t.Status.status_description, ip_address = t.ip_address, mac_address = t.mac_address, note = t.note, owner = t.owner, cost = t.cost, po_number = t.po_number, description = t.description, invoice_number = t.invoice_number, serial_number = t.serial_number, asset_tag_number = t.asset_tag_number, acquired_date = t.acquired_date, disposed_date = t.disposed_date, verified_date = t.verified_date, created_date = t.created_date, created_by = t.created_by, modified_date = t.modified_date, modified_by = t.modified_by }).ToList().AsQueryable().Select(select); return collection; } } } public class DynamicColumns : INV_Assets { public string Model { get; set; } public string Manufacturer { get; set; } public string Type { get; set; } public string Location { get; set; } public string Vendor { get; set; } public string Status { get; set; } public string ip_address { get; set; } public string mac_address { get; set; } public string note { get; set; } public string owner { get; set; } public string cost { get; set; } public string po_number { get; set; } public string description { get; set; } public string invoice_number { get; set; } public string serial_number { get; set; } public string asset_tag_number { get; set; } public string acquired_date { get; set; } public string disposed_date { get; set; } public string verified_date { get; set; } public string created_date { get; set; } public string created_by { get; set; } public string modified_date { get; set; } public string modified_by { get; set; } } public enum EnumTasks { Model = 1, Manufacturer = 2, Type = 3, Location = 4, Vendor = 5, Status = 6, ip_address = 7, mac_address = 8, note = 9, owner = 10, cost = 11, po_number = 12, description = 13, invoice_number = 14, serial_number = 15, asset_tag_number = 16, acquired_date = 17, disposed_date = 18, verified_date = 19, created_date = 20, created_by = 21, modified_date = 22, modified_by = 23 } //https://stackoverflow.com/questions/5796151/export-model-data-to-excel-mvc //https://landokal.wordpress.com/2011/04/28/asp-net-mvc-export-to-excel-trick/ }
我的代码是从我的View上的MultiSelectList中将我select的列值导出到Excel电子表格的第一行中，但是我的dynamiclinq查询有些问题，因为获取输出的数据只是A2:A180的值A2:A180无论如何我为输出指定了许多字段。
任何人谁拥有更多的经验或谁已经使用System.Linq.Dynamic权衡这个？
以下是我正在使用的一段时间：
public class ExcelExportHelper { public static string ExcelContentType { get { return "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"; } } public static DataTable ToDataTable<T>(List<T> data) { PropertyDescriptorCollection props = TypeDescriptor.GetProperties(typeof(T)); DataTable table = new DataTable(); for (int i = 0; i < props.Count; i++) { PropertyDescriptor prop = props[i]; //table.Columns.Add(prop.Name, prop.PropertyType); table.Columns.Add(prop.Name, Nullable.GetUnderlyingType(prop.PropertyType) ?? prop.PropertyType); // to avoid nullable types } object[] values = new object[props.Count]; foreach (T item in data) { for (int i = 0; i < values.Length; i++) { values[i] = props[i].GetValue(item); } table.Rows.Add(values); } return table; } public static byte[] ExportExcel(DataTable dt, string Heading = "", params string[] IgnoredColumns) { byte[] result = null; using (ExcelPackage pck = new ExcelPackage()) { ExcelWorksheet ws = pck.Workbook.Worksheets.Add("Exported Data"); int StartFromRow = String.IsNullOrEmpty(Heading) ? 1: 3; // add the content into the Excel file ws.Cells["A" + StartFromRow].LoadFromDataTable(dt, true); // autofit width of cells with small content int colindex = 1; foreach (DataColumn col in dt.Columns) { ExcelRange columnCells = ws.Cells[ws.Dimension.Start.Row, colindex, ws.Dimension.End.Row, colindex]; int maxLength = columnCells.Max(cell => cell.Value.ToString().Count()); if (maxLength < 150) ws.Column(colindex).AutoFit(); colindex++; } // format header - bold, yellow on black using (ExcelRange r = ws.Cells[StartFromRow, 1, StartFromRow, dt.Columns.Count]) { r.Style.Font.Color.SetColor(System.Drawing.Color.Yellow); r.Style.Font.Bold = true; r.Style.Fill.PatternType = OfficeOpenXml.Style.ExcelFillStyle.Solid; r.Style.Fill.BackgroundColor.SetColor(System.Drawing.Color.Black); } // format cells - add borders using (ExcelRange r = ws.Cells[StartFromRow + 1, 1, StartFromRow + dt.Rows.Count, dt.Columns.Count]) { r.Style.Border.Top.Style = ExcelBorderStyle.Thin; r.Style.Border.Bottom.Style = ExcelBorderStyle.Thin; r.Style.Border.Left.Style = ExcelBorderStyle.Thin; r.Style.Border.Right.Style = ExcelBorderStyle.Thin; r.Style.Border.Top.Color.SetColor(System.Drawing.Color.Black); r.Style.Border.Bottom.Color.SetColor(System.Drawing.Color.Black); r.Style.Border.Left.Color.SetColor(System.Drawing.Color.Black); r.Style.Border.Right.Color.SetColor(System.Drawing.Color.Black); } // removed ignored columns for (int i = dt.Columns.Count - 1; i >= 0; i--) { if (IgnoredColumns.Contains(dt.Columns[i].ColumnName)) { ws.DeleteColumn(i + 1); } } // add header and an additional column (left) and row (top) if (!String.IsNullOrEmpty(Heading)) { ws.Cells["A1"].Value = Heading; ws.Cells["A1"].Style.Font.Size = 20; ws.InsertColumn(1, 1); ws.InsertRow(1, 1); ws.Column(1).Width = 5; } result = pck.GetAsByteArray(); } return result; } public static byte[] ExportExcel<T>(List<T> data, string Heading = "", params string[] IgnoredColumns) { return ExportExcel(ToDataTable<T>(data), Heading, IgnoredColumns); } }
有了这些，您可以将对象或数据表的列表导出到Excel文件。 此外，你可以指定一个头和列/属性被忽略（如ID ）。 此外，还添加了一些格式，并且小单元格将自动适应宽度。
使用这段代码，你可以在期待FileResult控制器动作中使用FileResult ：
byte[] filecontent = ExcelExportHelper.ExportExcel(...); return File(filecontent, ExcelExportHelper.ExcelContentType, "FileName.xlsx");
我希望这有帮助！