Using SSRS 2016

Format.cs

[Serializable]
public enum Format
{
    XML,
    CSV,
    PDF,    
    EXCELOPENXML,    
    WORDOPENXML
}

Report.cs

public class Report
{
    public Report(string extension, string mimeType, byte[] results)
    {
        this.Extension = extension;
        this.MimeType = mimeType;
        this.Results = results;
    }

    public string Extension { get; private set; }
    public string MimeType { get; private set; }
    public byte[] Results { get; private set; }
}

SSRS.cs

//Project > References > Add Service Reference > http://<URL>/<APP_SSRS>/ReportExecution2005.asmx
//Add the SOAP Execution client

public class GenerateReportService
{
    
    private readonly SSRSEX.ReportExecutionServiceSoapClient clientEX;

    //NetworkCredential => CredentialCache.DefaultNetworkCredentials or new System.Net.NetworkCredential("user", "pass", "domain")

    public GenerateReportService(System.Net.NetworkCredential clientCredentials)
    {
        clientEX = new SSRSEX.ReportExecutionServiceSoapClient();
        clientEX.ClientCredentials.Windows.AllowedImpersonationLevel = System.Security.Principal.TokenImpersonationLevel.Impersonation;
        clientEX.ClientCredentials.Windows.ClientCredential = clientCredentials;
    }


    public Report Render(string reportName, IDictionary<string, string> parametros, Format format)
    {
        string mimeType = string.Empty;
        string extension = string.Empty;
        string historyID = null;
        string deviceInfo = null;
        byte[] results;
        string encoding = string.Empty;
        SSRSEX.Warning[] warnings = null;
        string[] streamIDs = null;

        clientEX.Open();

        SSRSEX.ServerInfoHeader serverInfoHeader = null;
        SSRSEX.ExecutionInfo executionInfo = null;
        SSRSEX.TrustedUserHeader trustedUserHeader = new SSRSEX.TrustedUserHeader();

        clientEX.LoadReport(trustedUserHeader, reportName, historyID, out serverInfoHeader, out executionInfo);
        SSRSEX.ParameterValue[] parameters = new SSRSEX.ParameterValue[1];

        List<ParameterValue> reportParameters = new List<ParameterValue>();

        foreach (var item in parameters)
        {
            reportParameters.Add(new ParameterValue
            {
                Name = item.Key,
                Value = item.Value
            });
        }

        SSRSEX.ExecutionHeader execHeader = new SSRSEX.ExecutionHeader();
        execHeader.ExecutionID = executionInfo.ExecutionID;

        clientEX.SetExecutionParameters(execHeader, trustedUserHeader, reportParameters.ToArray(), "pt-BR", out executionInfo);

        clientEX.Render(execHeader, trustedUserHeader, format.ToString(), deviceInfo,
            out results, out extension, out mimeType, out encoding, out warnings, out streamIDs);

        return new Report(extension, mimeType, results);

    }

    public async System.Threading.Tasks.Task<Report> RenderAsync(string reportName, IDictionary<string, string> parameters, Format format)
    {
        string historyID = null;
        string deviceInfo = null;
        string encoding = string.Empty;

        clientEX.Open();

        SSRSEX.ServerInfoHeader serverInfoHeader = null;
        SSRSEX.ExecutionInfo executionInfo = null;
        SSRSEX.TrustedUserHeader trustedUserHeader = new SSRSEX.TrustedUserHeader();

        clientEX.LoadReport(trustedUserHeader, reportName, historyID, out serverInfoHeader, out executionInfo);
        SSRSEX.ParameterValue[] parameters = new SSRSEX.ParameterValue[1];

        List<ParameterValue> reportParameters = new List<ParameterValue>();

        foreach (var item in parameters)
        {
            reportParameters.Add(new ParameterValue
            {
                Name = item.Key,
                Value = item.Value
            });
        }

        SSRSEX.ExecutionHeader execHeader = new SSRSEX.ExecutionHeader();
        execHeader.ExecutionID = executionInfo.ExecutionID;

        clientEX.SetExecutionParameters(execHeader, trustedUserHeader, reportParameters.ToArray(), "pt-BR", out executionInfo);

        SSRSEX.RenderRequest renderReq = new SSRSEX.RenderRequest(execHeader, trustedUserHeader, format.ToString(), deviceInfo);
        SSRSEX.RenderResponse taskRender = await clientEX.RenderAsync(renderReq);

        return new Report(taskRender.Extension, taskRender.MimeType, taskRender.Result);

    }

  }

UsingController.cs

public class UsingController
{

    private readonly GenerateReportService executer;

    public UsingController(GenerateReportService executer)
    {
        this.executer = executer;
    }

    public async System.Threading.Tasks.Task<ActionResult> IndexOne(int year, string format)
    {
        var parameters = new Dictionary<string, string>();

        parameters.Add("Year", year.ToString());

        var reportFormat = (Format)Enum.Parse(typeof(Format), format);

        var relatorio = await this.executer.RenderAsync("reportName", parameters, format);

        return File(relatorio.Results, relatorio.MimeType, string.Format("relatorio.{0}", relatorio.Extension));
    }

    public ActionResult IndexTwo(string format)
    {
        var parameters = new Dictionary<string, string>();

        parameters.Add("Year", year.ToString());

        var reportFormat = (Format)Enum.Parse(typeof(Format), format);

        var relatorio = this.executer.Render("reportName", parameters, format);

        return File(relatorio.Results, relatorio.MimeType, string.Format("relatorio.{0}", relatorio.Extension));
    }


}