[英]How do I export to Excel?
我遵循了在另一篇关于此的帖子中推荐的本指南,但我无法使其正常工作。 尝试重定向到 /LogModelsController/ExportData 时出现 404 错误,正如我所理解的,这是我应该做的。
_LogPartialLayout.cshtml
@using (Html.BeginForm("ExportData", "LogModelsController", FormMethod.Post, new { enctype = "multipart/form-data" }))
{
<table class="table">
<tr>
<th>
@Html.ActionLink("message", "Index", new { sortOrder = ViewBag.NameSortParm, currentFilter = ViewBag.CurrentFilter })
</th>
<th>
@Html.ActionLink("timestamp", "Index", new { sortOrder = ViewBag.NameSortParm, currentFilter = ViewBag.CurrentFilter })
</th>
<th>
@Html.ActionLink("level", "Index", new { sortOrder = ViewBag.NameSortParm, currentFilter = ViewBag.CurrentFilter })
</th>
</tr>
@foreach (var item in Model)
{
<tr>
<td>
@Html.DisplayFor(modelItem => item.message)
</td>
<td>
@Html.DisplayFor(modelItem => item.timeStamp)
</td>
<td>
@Html.DisplayFor(modelItem => item.level)
</td>
</tr>
}
</table>
<input type="submit" name="Export" id="Export" value="Export" />
}
LogModelsController.cs
public ActionResult ExportData()
{
GridView gv = new GridView();
gv.DataSource = db.Log.ToList();
gv.DataBind();
Response.ClearContent();
Response.Buffer = true;
Response.AddHeader("content-disposition", "attachment; filename=Loglist.xls");
Response.ContentType = "application/ms-excel";
Response.Charset = "";
StringWriter sw = new StringWriter();
HtmlTextWriter htw = new HtmlTextWriter(sw);
gv.RenderControl(htw);
Response.Output.Write(sw.ToString());
Response.Flush();
Response.End();
return RedirectToAction("~/LogModels/Index");
}
日志模型.cs
namespace ASDMVC.Models
{
[Table("Log")]
public class LogModel
{
[Key]
public long id { get; set; }
public string message { get; set; }
public DateTime timeStamp { get; set; }
public string level { get; set; }
public int customerId { get; set; }
}
public class LogDBContext:DbContext
{
public LogDBContext() : base("MySqlConnection")
{
}
public DbSet <LogModel> Log { get; set; }
}
}
TD;DR:如何将此表正确导出到 Excel?
奖励:它也适用于 PagedList 吗?
索引.cshtml:
@using (Html.BeginForm("ExportData", "LogModels"))
{
<input type="submit" name="Export" id="Export" value="Export" />
}
LogModelsController.cs
public ActionResult ExportData()
{
DataTable dataTable = GetData();
using (ExcelPackage package = new ExcelPackage())
{
var ws = package.Workbook.Worksheets.Add("My Sheet");
//true generates headers
ws.Cells["A1"].LoadFromDataTable(dataTable, true);
var stream = new MemoryStream();
package.SaveAs(stream);
string fileName = "myfilename.xlsx";
string contentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
stream.Position = 0;
return File(stream, contentType, fileName);
}
}
public DataTable GetData()
{
DataTable dt = new DataTable();
if (ModelState.IsValid)
{
using (SqlConnection conn = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["MySqlConnection"].ConnectionString))
{
using (SqlCommand comm = conn.CreateCommand())
{
comm.Parameters.AddWithValue("@val1", Session["myID"]);
comm.CommandText = "SELECT * FROM dbo.Log WHERE CustomerId = @val1";
try
{
conn.Open();
dt.Load(comm.ExecuteReader());
}
catch (SqlException e)
{
throw new Exception(e.ToString());
}
}
}
}
return dt;
}
我在 CommandText 中犯了一个错误,把“Id”而不是“CustomerId” - 它现在返回 Excel 文件中的整个表。
该指南没有展示如何创建 Excel 文件,它展示了一种使用表格创建 HTML 文件的技巧。 Excel 将尝试使用通常会失败的默认设置导入带有表格的 csv 或 HTML 文件。
使用像EPPlus这样的库创建合适的Excel 文件要容易得多。 我确定之前已经回答过这个问题,但我找不到一个答案来显示如何从数据创建 Excel 文件并为xlsx
文件设置正确的内容类型。
EPPlus 提供 LoadFromDataTable 和 LoadFromCollection 方法来使用从 DataTable 或通用集合中提取的数据填充 Excel 范围。 列名或属性名分别用作标题。
public ActionResult ExportData()
{
//Somehow, load data to a DataTable
using (ExcelPackage package = new ExcelPackage())
{
var ws = package.Workbook.Worksheets.Add("My Sheet");
//true generates headers
ws.Cells["A1"].LoadFromDataTable(dataTable, true);
var stream = new MemoryStream();
package.SaveAs(stream);
string fileName = "myfilename.xlsx";
string contentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
stream.Position = 0;
return File(stream, contentType, fileName);
}
}
LoadFromDataTable 或 LoadFromCollection 返回可用于格式化表格的 Excel 单元格范围:
var range=ws.Cells["A1"].LoadFromDataTable(table);
range.Style.Numberformat.Format = "#,##0.00";
range.Style.HorizontalAlignment = ExcelHorizontalAlignment.Right;
您还可以将表格样式应用于范围,或将所需样式传递给LoadFromDataTable
或LoadFromCollection
,例如:
ws.Cells[1,1].LoadFromDataTable(table, true, TableStyles.Light1);
该库的Githup wiki展示了如何格式化结果、生成公式、数据透视表、处理表格等。
如果您想创建一个相对较大的工作表,保存到 MemoryStream 可能是一个问题。 两次写入相同的数据,一次写入 MemoryStream,然后将其复制到输出,浪费周期。 但是,从 MVC 操作直接写入输出流是一种不好的做法。 诀窍是创建一个自定义 FileResult 来处理 EPPlus 包并返回它而不是File
返回的 FileResult ,例如:
public class EpplusResult:FileResult
{
public EpplusResult(ExcelPackage package)
: base("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet")
{
if (package == null)
{
throw new ArgumentNullException("package");
}
Package = package;
}
public ExcelPackage Package { get; private set; }
protected override void WriteFile(HttpResponseBase response)
{
// grab chunks of data and write to the output stream
Stream outputStream = response.OutputStream;
using (Package)
{
Package.SaveAs(outputStream);
}
}
}
这允许您编写以下操作:
public FileResult ExportData()
{
ExcelPackage package = new ExcelPackage();
var ws = package.Workbook.Worksheets.Add("My Sheet");
...
ws.Cells[1,1].LoadFromDataTable(table, true, TableStyles.Light1);
return new EpplusResult(package){FileDownloadName = "SomeFile.xlsx"};
}
不要创建基于 HTML 的 excel 文件,它们有很多问题。
Insteed 使用一个紧凑的库,例如epplus 。
public ActionResult ExportData()
{
using (ExcelPackage package = new ExcelPackage())
{
var ws = package.Workbook.Worksheets.Add("LogMessages");
//Headers
ws.Cells["A1"].Value = "Message";
ws.Cells["B1"].Value = "TimeStamp";
ws.Cells["C1"].Value = "Level";
var rowNumber=1;
foreach (var log in DbContext.Log)
{
ws.Cells[rowNumber, 1].Value = vehicle.message;
ws.Cells[rowNumber, 2].Value = vehicle.timeStamp;
ws.Cells[rowNumber, 3].Value = vehicle.level;
rowNumber++;
}
var stream = new MemoryStream();
package.SaveAs(stream);
string fileName = "logMessags.xlsx";
string contentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
stream.Position = 0;
return File(stream, contentType, fileName);
}
}
我已经使用 Panagiotis Kanavos 代码结构来实现这个解决方案
看看这个,这个库包含一个 ExcelResult,它将自动创建过程,并通过调用 Excel() 方法将 Excel 文件发送到客户端,就像 Json()。
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