CreateStreamCallback 委派

發行項
08/20/2007

提供資料流給 ReportViewer 控制項進行轉譯。

命名空間: Microsoft.Reporting.WebForms
組件: Microsoft.ReportViewer.WebForms (在 microsoft.reportviewer.webforms.dll)

語法

'宣告
Public Delegate Function CreateStreamCallback ( _
    name As String, _
    extension As String, _
    encoding As Encoding, _
    mimeType As String, _
    willSeek As Boolean _
) As Stream
'用途
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
)

/** @delegate */
public delegate Stream CreateStreamCallback (
    String name, 
    String extension, 
    Encoding encoding, 
    String mimeType, 
    boolean willSeek
)

JScript supports the use of delegates, but not the declaration of new ones.

參數

name
資料流的名稱。

extension
如果建立檔案資料流時，所用的副檔名。

encoding
指定資料流字元編碼的 Encoding 列舉值。如果資料流未包含字元，這可能是 null。

mimeType
包含資料流 MIME 類型的字串。

willSeek
這是一個 Boolean 值，用來指示資料流是否需要支援搜尋。如果這個值是 false，資料流是順向的，當建立資料流時，會將資料流以區塊的方式傳給用戶端。如果值是 true，就可能依照任何順序來寫入資料流。

傳回值

這是 ReportViewer 控制項可將資料寫入其中的 Stream 物件。

備註

這個委託函數可傳入 LocalReport 物件的 Render 方法來支援次要資料流的自訂處理。報表的主體是所建立的第一個資料流。

範例

下列程式碼片段顯示傳遞至 Render 方法的 CreateStreamCallback 回呼函數。

Imports System.IO
Imports System.Data
Imports System.Text
Imports System.Drawing.Imaging
Imports System.Drawing.Printing
Imports System.Collections.Generic
Imports Microsoft.Reporting.WebForms

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.WebForms;

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;
    }
}

另請參閱

參考

Microsoft.Reporting.WebForms 命名空間

共用方式為

CreateStreamCallback 委派

語法

參數

傳回值

備註

範例

另請參閱

參考

其他資源