Delegato CreateStreamCallback
Restituisce al controllo ReportViewer un flusso per il rendering.
Spazio dei nomi Microsoft.Reporting.WinForms
Assembly: Microsoft.ReportViewer.WinForms (in Microsoft.ReportViewer.WinForms.dll)
Sintassi
'Dichiarazione
Public Delegate Function CreateStreamCallback ( _
name As String, _
extension As String, _
encoding As Encoding, _
mimeType As String, _
willSeek As Boolean _
) As Stream
'Utilizzo
Dim instance As New CreateStreamCallback(AddressOf HandlerMethod)
public delegate Stream CreateStreamCallback(
string name,
string extension,
Encoding encoding,
string mimeType,
bool willSeek
)
public delegate Stream^ CreateStreamCallback(
String^ name,
String^ extension,
Encoding^ encoding,
String^ mimeType,
bool willSeek
)
type CreateStreamCallback =
delegate of
name:string *
extension:string *
encoding:Encoding *
mimeType:string *
willSeek:bool -> Stream
JScript supporta l'utilizzo di delegati, ma non la dichiarazione di nuovi delegati.
Parametri
- name
Tipo: System.String
Nome del flusso.
- extension
Tipo: System.String
Estensione da utilizzare se viene creato un flusso di file.
- encoding
Tipo: System.Text.Encoding
Valore di enumeratore Encoding che specifica la codifica dei caratteri del flusso. Il valore può essere nullriferimento Null (Nothing in Visual Basic). se il flusso non contiene caratteri.
- mimeType
Tipo: System.String
Valore String contenente il tipo MIME del flusso.
- willSeek
Tipo: System.Boolean
Valore Boolean che indica se il flusso deve supportare la ricerca. Se ha valore false, il flusso sarà forward-only e verrà inviato al client in blocchi durante la creazione. Se ha valore true, è possibile scrivere nel flusso in qualsiasi ordine.
Valore restituito
Tipo: System.IO.Stream
Oggetto Stream in cui il controllo ReportViewer può scrivere dati.
Osservazioni
È possibile passare questa funzione di delegato nel metodo Render(IRenderingExtension, String, String, CreateAndRegisterStream, array<Warning[]%) dell'oggetto LocalReport() per supportare la gestione personalizzata dei flussi secondari. Il primo flusso creato è il corpo principale del rapporto.
Esempi
Nel frammento di codice seguente una funzione di richiamata CreateStreamCallback viene passata al metodo Render in un'applicazione console.
Imports System.IO
Imports System.Data
Imports System.Text
Imports System.Drawing.Imaging
Imports System.Drawing.Printing
Imports System.Collections.Generic
Imports Microsoft.Reporting.WinForms
Public Class Demo
Implements IDisposable
private m_currentPageIndex As Integer
private m_streams As IList(Of Stream)
Private Function LoadSalesData() As DataTable
Dim dataSet As New DataSet()
dataSet.ReadXml("data.xml")
Return dataSet.Tables(0)
End Function
Private Function CreateStream(name As String, _
fileNameExtension As String, _
encoding As Encoding, mimeType As String, _
willSeek As Boolean) As Stream
Dim stream As Stream = New FileStream(name + "." + fileNameExtension, FileMode.Create)
m_streams.Add(stream)
Return stream
End Function
Private Sub Export(report As LocalReport)
Dim deviceInfo As string = _
"<DeviceInfo>" + _
" <OutputFormat>EMF</OutputFormat>" + _
" <PageWidth>8.5in</PageWidth>" + _
" <PageHeight>11in</PageHeight>" + _
" <MarginTop>0.25in</MarginTop>" + _
" <MarginLeft>0.25in</MarginLeft>" + _
" <MarginRight>0.25in</MarginRight>" + _
" <MarginBottom>0.25in</MarginBottom>" + _
"</DeviceInfo>"
Dim warnings() As Warning = Nothing
m_streams = New List(Of Stream)()
report.Render("Image", deviceInfo, _
AddressOf CreateStream, warnings)
Dim stream As Stream
For Each stream In m_streams
stream.Position = 0
Next
End Sub
Private Sub PrintPage(sender As Object, ev As PrintPageEventArgs)
Dim pageImage As New Metafile(m_streams(m_currentPageIndex))
ev.Graphics.DrawImage(pageImage, ev.PageBounds)
m_currentPageIndex += 1
ev.HasMorePages = (m_currentPageIndex < m_streams.Count)
End Sub
Private Sub Print()
Const printerName As String = "Microsoft Office Document Image Writer"
If m_streams Is Nothing Or m_streams.Count = 0 Then
Return
End If
Dim printDoc As New PrintDocument()
printDoc.PrinterSettings.PrinterName = printerName
If Not printDoc.PrinterSettings.IsValid Then
Dim msg As String = String.Format(_
"Can't find printer ""{0}"".", printerName)
Console.WriteLine(msg)
Return
End If
AddHandler printDoc.PrintPage, AddressOf PrintPage
printDoc.Print()
End Sub
Private Sub Run()
Dim report As LocalReport = new LocalReport()
report.ReportPath = "Report.rdlc"
report.DataSources.Add(new ReportDataSource("Sales", LoadSalesData()))
Export(report)
m_currentPageIndex = 0
Print()
End Sub
Public Overloads Sub Dispose() Implements IDisposable.Dispose
If Not (m_streams Is Nothing) Then
Dim stream As Stream
For Each stream In m_streams
stream.Close()
Next
m_streams = Nothing
End If
End Sub
Public Shared Sub Main(args as string())
Using demo As Demo = new Demo()
demo.Run()
End Using
End Sub
End Class
using System;
using System.IO;
using System.Data;
using System.Text;
using System.Drawing.Imaging;
using System.Drawing.Printing;
using System.Collections.Generic;
using Microsoft.Reporting.WinForms;
public class Demo : IDisposable
{
private int m_currentPageIndex;
private IList<Stream> m_streams;
private DataTable LoadSalesData()
{
DataSet dataSet = new DataSet();
dataSet.ReadXml("data.xml");
return dataSet.Tables[0];
}
private Stream CreateStream(string name, string fileNameExtension, Encoding encoding,
string mimeType, bool willSeek)
{
Stream stream = new FileStream(name + "." + fileNameExtension, FileMode.Create);
m_streams.Add(stream);
return stream;
}
private void Export(LocalReport report)
{
string deviceInfo =
"<DeviceInfo>" +
" <OutputFormat>EMF</OutputFormat>" +
" <PageWidth>8.5in</PageWidth>" +
" <PageHeight>11in</PageHeight>" +
" <MarginTop>0.25in</MarginTop>" +
" <MarginLeft>0.25in</MarginLeft>" +
" <MarginRight>0.25in</MarginRight>" +
" <MarginBottom>0.25in</MarginBottom>" +
"</DeviceInfo>";
Warning[] warnings;
m_streams = new List<Stream>();
report.Render("Image", deviceInfo, CreateStream, out warnings);
foreach (Stream stream in m_streams)
stream.Position = 0;
}
private void PrintPage(object sender, PrintPageEventArgs ev)
{
Metafile pageImage = new Metafile(m_streams[m_currentPageIndex]);
ev.Graphics.DrawImage(pageImage, 0, 0);
m_currentPageIndex++;
ev.HasMorePages = (m_currentPageIndex < m_streams.Count);
}
private void Print()
{
const string printerName = "Microsoft Office Document Image Writer";
if (m_streams == null || m_streams.Count == 0)
return;
PrintDocument printDoc = new PrintDocument();
printDoc.PrinterSettings.PrinterName = printerName;
if (!printDoc.PrinterSettings.IsValid)
{
string msg = String.Format("Can't find printer \"{0}\".", printerName);
Console.WriteLine(msg);
return;
}
printDoc.PrintPage += new PrintPageEventHandler(PrintPage);
printDoc.Print();
}
private void Run()
{
LocalReport report = new LocalReport();
report.ReportPath = "Report.rdlc";
report.DataSources.Add(new ReportDataSource("Sales", LoadSalesData()));
Export(report);
m_currentPageIndex = 0;
Print();
}
public void Dispose()
{
if (m_streams != null)
{
foreach (Stream stream in m_streams)
stream.Close();
m_streans = null;
}
}
public static int Main(string[] args)
{
using (Demo demo = new Demo())
{
demo.Run();
}
return 0;
}
}