So I want to let users to export reports from the website as an end user, without using power Bi application. I already has everything set server side, I am following this code sample from

        /* ********** Export reports functionality ********** */

    private async Task<string> PostExportRequest(Guid reportId,Guid groupId)
    {
        // For documentation purposes the export configuration is created in this method
        // Ordinarily, it would be created outside and passed in
        var paginatedReportExportConfiguration = new PaginatedReportExportConfiguration()
        {
            FormatSettings = new Dictionary<string, string>()
    {
        {"PageHeight", "14in"},
        {"PageWidth", "8.5in" },
        {"StartPage", "1"},
        {"EndPage", "4"},
    },
            ParameterValues = new List<ParameterValue>()
    {
        { new ParameterValue() {Name = "State", Value = "WA"} },
        { new ParameterValue() {Name = "City", Value = "Redmond"} },
    },
        };

        var exportRequest = new ExportReportRequest
        {
            Format = FileFormat.PDF,
            PaginatedReportExportConfiguration = paginatedReportExportConfiguration,
        };

        var export = await Client.Reports.ExportToFileInGroupAsync(groupId, reportId, exportRequest);

        // Save the export ID, you'll need it for polling and getting the exported file
        return export.Id;
    }

    private async Task<Export> PollExportRequest(
    Guid reportId,
    Guid groupId,
    string exportId /* Get from the ExportToAsync response */,
    int timeOutInMinutes,
    CancellationToken token)
{
    Export exportStatus = null;
    DateTime startTime = DateTime.UtcNow;
    const int secToMillisec = 1000;
    do
    {
        if (DateTime.UtcNow.Subtract(startTime).TotalMinutes > timeOutInMinutes || token.IsCancellationRequested)
        {
            // Error handling for timeout and cancellations
            return null;
        }

        var httpMessage = 
            await Client.Reports.GetExportToFileStatusInGroupWithHttpMessagesAsync(groupId, reportId, exportId);
            
        exportStatus = httpMessage.Body;
        if (exportStatus.Status == ExportState.Running || exportStatus.Status == ExportState.NotStarted)
        {
            // The recommended waiting time between polling requests can be found in the RetryAfter header
            // Note that this header is only populated when the status is either Running or NotStarted
            var retryAfter = httpMessage.Response.Headers.RetryAfter;
            var retryAfterInSec = retryAfter.Delta.Value.Seconds;

            await Task.Delay(retryAfterInSec * secToMillisec);
        }
    }
    // While not in a terminal state, keep polling
    while (exportStatus.Status != ExportState.Succeeded && exportStatus.Status != ExportState.Failed);

    return exportStatus;
}
    private async Task<ExportedFile> GetExportedFile(
        Guid reportId,
        Guid groupId,
        Export export /* Get from the GetExportStatusAsync response */)
    {
        if (export.Status == ExportState.Succeeded)
        {
            var httpMessage =
                await Client.Reports.GetFileOfExportToFileInGroupWithHttpMessagesAsync(groupId, reportId, export.Id);

            return new ExportedFile
            {
                FileStream = httpMessage.Body,
                ReportName = export.ReportName,
                FileExtension = export.ResourceFileExtension,
            };
        }

        return null;
    }

    public class ExportedFile
    {
        public Stream FileStream;
        public string ReportName;
        public string FileExtension;
    }

    private async Task<ExportedFile> ExportPaginatedReport(
        Guid reportId,
        Guid groupId,
        int pollingtimeOutInMinutes,
        CancellationToken token)
    {
        try
        {
            var exportId = await PostExportRequest(reportId, groupId);

            var export = await PollExportRequest(reportId, groupId, exportId, pollingtimeOutInMinutes, token);
            if (export == null || export.Status != ExportState.Succeeded)
            {
                // Error, failure in exporting the report
                return null;
            }

            return await GetExportedFile(reportId, groupId, export);
        }
        catch
        {
            // Error handling
            throw;
        }
    }

CodePudding user response：

Looking at the errors from your screenshots, it looks like you didn't added the Power BI SDK (also see Power BI Embedded libraries for .NET). You must install Microsoft.PowerBI.Api NuGetPackage. One way to do that is to run the following command in the package manager in Visual Studio:

Install-Package Microsoft.PowerBI.Api