我使用ASP.NET C＃和angular 8开发了一个Web API。我尝试将一些数据从Oracle导出到服务器端的Excel文件中（使用NPOI）并在客户端下载。我可以看到memoryStream包含数据，但是在“返回响应”上，它没有返回给客户端，而是再次调用了该函数。这是我的代码：
HTML：
<button
class="col-sm-2 button-style button-text"
style="color: white; background-color: #19D893;height: 100%;"
(click)="exportPriceList()">
Export
</button>类型脚本：
public exportPriceList(): void {
let fileName='filename';
const fileType = 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet';
console.log('before promise');
const promise = new Promise((resolve, reject) => {
this.export().subscribe(
success => {
console.log('start success');
const blob = new Blob ([success], {type: fileType});
console.log('window.navigator ', window.navigator );
console.log('window.navigator.msSaveOrOpenBlob ', window.navigator.msSaveOrOpenBlob );
if (window.navigator && window.navigator.msSaveOrOpenBlob) {
window.navigator.msSaveOrOpenBlob(blob, );
} else {
const a = document.createElement('a');
a.href = URL.createObjectURL(blob);
a.download = fileName ;
document.body.appendChild(a);
a.click();
document.body.removeChild(a);
}
},
err => {
alert(err);
});
});
promise.then((res) => {
console.log('promise!!!! ', res );
});
promise.catch((err) => {
});
}public export()
{
console.log('start export to excel');
const fileName = 'filename1';
const fileType = 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet';
const url = this.apiService.baseUrl + 'api/PriceList/Export?token=' + this.auth.authDetails.getValue().token +
'&priceListType=' + this.selectedPriceListType.Key + '&fileType=' + fileType + '&bank=' + this.selectedBank.Key;
return this.http.get(url, {responseType: 'arraybuffer'});// this.http.get(url, {responseType: 'blob'});
}API控制器：
[HttpGet]
[Route("api/PriceList/Export")]
public HttpResponseMessage Export([FromUri]string token, [FromUri]int priceListType,[FromUri]string fileType, [FromUri]int? bank=null)
{
try
{
var stream = dal.ExportPriceListServer(priceListType, bank);
var response = new HttpResponseMessage(System.Net.HttpStatusCode.OK);
response.Content = new StreamContent(stream);
response.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
{
FileName= "PriceList_" + bank + "_" + DateTime.Now.ToString("yyyyMMdd") + ".xlsx"
};
response.Content.Headers.ContentType = new MediaTypeHeaderValue(fileType);
return response;
}
catch (Exception ex)
{
exc.throwException(EventLogEntryType.Error, ex.ToString());
throw;
}
}
DAL ：（生成Excel的最终函数。）
public MemoryStream ExportToExcel(DataTable dt)
{
try
{
using (var stream = new MemoryStream())
{
// Declare XSSFWorkbook object for create sheet
var workbook = new XSSFWorkbook();
var sheet = workbook.CreateSheet("sheet 1");
int rowIndex = 0;
var headerRow = sheet.CreateRow(1);
//Below loop is create header
foreach (DataColumn column in dt.Columns)
{
XSSFCell xc = (XSSFCell)headerRow.CreateCell(column.Ordinal);
xc.SetCellValue(GetColumnTitle(column.ColumnName));
//xc.CellStyle = xstl;
}
rowIndex = 2;
foreach (DataRow row in dt.Rows)
{
XSSFRow dataRow = (XSSFRow)(sheet.CreateRow(rowIndex));
foreach (DataColumn column in dt.Columns)
{
XSSFCell c = (XSSFCell)dataRow.CreateCell(column.Ordinal);
string val = row[column].ToString();
int x;
if (Int32.TryParse(val, out x) && (!String.IsNullOrEmpty(val)))//column.IsNumeric()
{
c.SetCellValue(Int64.Parse(val));
c.SetCellType(CellType.Numeric);
}
else
{
c.SetCellValue(row[column].ToString());
}
// no need to auto size all the time, after 100 is ok... (it costs a lot)
if (rowIndex == 100)
{
sheet.AutoSizeColumn(column.Ordinal);
}
}
rowIndex++;
}
// Declare one MemoryStream variable for write file in stream
workbook.Write(stream, true);
return stream;
}
}
catch (Exception ex)
{
Console.Write(ex);
return null;
}
}
这是我在chrome调试器中看到的内容：[网络] [1]
在时间上，我看到“ Stallen”：[Stallen] [2]
rates.component.ts:100 before promise zone.js:2969 GET ..... **net::ERR_CONNECTION_RESET** scheduleTask @ zone.js:2969 push../node_modules/zone.js/dist/zone.js.ZoneDelegate.scheduleTask @ zone.js:407 onScheduleTask @ zone.js:297 push../node_modules/zone.js/dist/zone.js.ZoneDelegate.scheduleTask @ zone.js:401 push../node_modules/zone.js/dist/zone.js.Zone.scheduleTask @ zone.js:232 push../node_modules/zone.js/dist/zone.js.Zone.scheduleMacroTask @ zone.js:255 scheduleMacroTaskWithCurrentZone @ zone.js:1114 (anonymous) @ zone.js:3001 proto.<computed> @ zone.js:1394 (anonymous) @ http.js:1630 push../node_modules/rxjs/_esm5/internal/Observable.js.Observable._trySubscribe@ Observable.js：43推送../node_modules/rxjs/_esm5/internal/Observable.js.Observable.subscribe@ Observable.js：29push ../ node_modules / rxjs / _esm5 / internal / operators / finalize.js.FinallyOperator.call@ finalize.js：13推送../node_modules/rxjs/_esm5/internal/Observable.js.Observable.subscribe@ Observable.js：24（匿名）@ subscriptionTo.js：21subscriptionToResult @ subscribeToResult.js：11推送../node_modules/rxjs/_esm5/internal/operators/mergeMap.js.MergeMapSubscriber._innerSub@ mergeMap.js：74推送../node_modules/rxjs/_esm5/internal/operators/mergeMap.js.MergeMapSubscriber._tryNext@ mergeMap.js：68推送../node_modules/rxjs/_esm5/internal/operators/mergeMap.js.MergeMapSubscriber._next@ mergeMap.js：51推送../node_modules/rxjs/_esm5/internal/Subscriber.js.Subscriber.next@ Subscriber.js：54（匿名）@ scalar.js：5推送../node_modules/rxjs/_esm5/internal/Observable.js.Observable._trySubscribe@ Observable.js：43推送../node_modules/rxjs/_esm5/internal/Observable.js.Observable.subscribe@ Observable.js：29推送../node_modules/rxjs/_esm5/internal/operators/mergeMap.js.MergeMapOperator.call@ mergeMap.js：29推送../node_modules/rxjs/_esm5/internal/Observable.js.Observable.subscribe@ Observable.js：24push ../ node_modules / rxjs / _esm5 / internal / operators / filter.js.FilterOperator.call@ filter.js：15推送../node_modules/rxjs/_esm5/internal/Observable.js.Observable.subscribe@ Observable.js：24push ../ node_modules / rxjs / _esm5 / internal / operators / map.js.MapOperator.call@ map.js：18推送../node_modules/rxjs/_esm5/internal/Observable.js.Observable.subscribe@ Observable.js：24（匿名）@ rates.component.ts：144ZoneAwarePromise @ zone.js：891push ../ src / app / Components / content / rates / rates.component.ts.RatesComponent.exportPriceList@ rates.component.ts：143评估@ RatesComponent.html：100handleEvent @ core.js：19545callWithDebugContext @ core.js：20639debugHandleEvent @ core.js：20342dispatchEvent @ core.js：16994（匿名）@ core.js：17441（匿名）@ platform-browser.js：993push ../ node_modules / zone.js / dist / zone.js.ZoneDelegate.invokeTask @ zone.js：421onInvokeTask @ core.js：14051push ../ node_modules / zone.js / dist / zone.js.ZoneDelegate.invokeTask @ zone.js：420push ../ node_modules / zone.js / dist / zone.js.Zone.runTask @ zone.js：188push ../ node_modules / zone.js / dist / zone.js.ZoneTask.invokeTask @ zone.js：496invokeTask @ zone.js：1540globalZoneAwareCallback @ zone.js：1566
你对我有什么解决办法吗？
谢谢，
我解决了问题。我更改代码：
API控制器：
MemoryStream stream = dal.ExportPriceListServer(priceListType);
var response = new HttpResponseMessage(System.Net.HttpStatusCode.OK);
response.Content = new ByteArrayContent(stream.ToArray());
response.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
{
FileName = "test.xlsx"
};
response.Content.Headers.ContentType = new MediaTypeHeaderValue(fileType);
return response;
DAL：使用“仅用于写入流”包围
// Declare one MemoryStream variable for write file in stream
using (var stream = new MemoryStream())
{
workbook.Write(stream, true);
return stream;
}