IWebPartRow.GetRowData(RowCallback) Metodo

Riferimento

Definizione

Spazio dei nomi:: System.Web.UI.WebControls.WebParts

Assembly:: System.Web.dll

Importante

Alcune informazioni sono relative alla release non definitiva del prodotto, che potrebbe subire modifiche significative prima della release definitiva. Microsoft non riconosce alcuna garanzia, espressa o implicita, in merito alle informazioni qui fornite.

Restituisce i dati per la riga utilizzata dall'interfaccia come base della connessione tra due controlli WebPart.

public:
 void GetRowData(System::Web::UI::WebControls::WebParts::RowCallback ^ callback);

public void GetRowData (System.Web.UI.WebControls.WebParts.RowCallback callback);

abstract member GetRowData : System.Web.UI.WebControls.WebParts.RowCallback -> unit

Public Sub GetRowData (callback As RowCallback)

Parametri

callback: RowCallback

Delegato RowCallback contenente l'indirizzo di un metodo che riceve i dati.

Esempio

Nell'esempio di codice seguente viene illustrata l'implementazione e l'uso del GetRowData metodo . L'esempio completo è illustrato nella panoramica della classe per l'interfaccia IWebPartRow . Il controllo provider implementa il GetRowData metodo , restituendo il valore di una determinata riga nella tabella dati. Il controllo consumer chiama il GetRowData metodo nel relativo OnPreRender metodo, in modo che il valore dei dati possa essere scritto nella pagina.

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Reflection;
using System.Security.Permissions;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;

namespace Samples.AspNet.CS.Controls 
{
  // This sample code creates a Web Parts control that acts as a provider 
  // of row data.
  [AspNetHostingPermission(SecurityAction.Demand,
    Level = AspNetHostingPermissionLevel.Minimal)]
  [AspNetHostingPermission(SecurityAction.InheritanceDemand,
    Level = AspNetHostingPermissionLevel.Minimal)]
  public sealed class RowProviderWebPart : WebPart, IWebPartRow 
    {
    private DataTable _table;
    
    public RowProviderWebPart() 
        {
      _table = new DataTable();

      DataColumn col = new DataColumn();
      col.DataType = typeof(string);
      col.ColumnName = "Name";
      _table.Columns.Add(col);

      col = new DataColumn();
      col.DataType = typeof(string);
      col.ColumnName = "Address";
      _table.Columns.Add(col);

      col = new DataColumn();
      col.DataType = typeof(int);
      col.ColumnName = "ZIP Code";
      _table.Columns.Add(col);

      DataRow row = _table.NewRow();
      row["Name"] = "John Q. Public";
      row["Address"] = "123 Main Street";
      row["ZIP Code"] = 98000;
      _table.Rows.Add(row);
    }

    [ConnectionProvider("Row")]
    public IWebPartRow GetConnectionInterface()
        {
      return new RowProviderWebPart();
    }

    public PropertyDescriptorCollection Schema 
        {
      get 
      {
        return TypeDescriptor.GetProperties(_table.DefaultView[0]);
            }
    }

        public void GetRowData(RowCallback callback)
        {
            callback(_table.Rows);
        }
  } // RowProviderWebPart

  // This sample code creates a Web Parts control that acts as a consumer 
  // of row data.
  [AspNetHostingPermission(SecurityAction.Demand,
    Level = AspNetHostingPermissionLevel.Minimal)]
  [AspNetHostingPermission(SecurityAction.InheritanceDemand,
    Level = AspNetHostingPermissionLevel.Minimal)]  
  public sealed class RowConsumerWebPart : WebPart 
  {
    private IWebPartRow _provider;
        private ICollection _tableData;
    
        private void GetRowData(object rowData)
        {
            _tableData = (ICollection)rowData;
        }

        protected override void OnPreRender(EventArgs e)
        {
            if (_provider != null)
            {
                _provider.GetRowData(new RowCallback(GetRowData));
            }
        }

    protected override void RenderContents(HtmlTextWriter writer) 
    {
      if (_provider != null) 
      {
        PropertyDescriptorCollection props = _provider.Schema;
            int count = 0;
        if (props != null && props.Count > 0 && _tableData != null) 
        {
            foreach (PropertyDescriptor prop in props) 
                  {
                      foreach (DataRow o in _tableData)
                      {
                          writer.Write(prop.DisplayName + ": " + o[count]);
                          writer.WriteBreak();
                          writer.WriteLine();
                          count = count + 1;
                      }
            }
        }
        else 
        {
          writer.Write("No data");
        }
      }
      else 
      {
        writer.Write("Not connected");
      }
    }

    [ConnectionConsumer("Row")]
    public void SetConnectionInterface(IWebPartRow provider) 
        {
      _provider = provider;
    }
  } // RowConsumerWebPart
} // Samples.AspNet.CS.Controls

Imports System.Collections
Imports System.ComponentModel
Imports System.Data
Imports System.Reflection
Imports System.Security.Permissions
Imports System.Web
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Web.UI.WebControls.WebParts

Namespace Samples.AspNet.VB.Controls

  ' This sample code creates a Web Parts control that acts as a provider 
  ' of row data.
  <AspNetHostingPermission(SecurityAction.Demand, _
    Level:=AspNetHostingPermissionLevel.Minimal)> _
  <AspNetHostingPermission(SecurityAction.InheritanceDemand, _
    Level:=AspNetHostingPermissionLevel.Minimal)> _
  Public NotInheritable Class RowProviderWebPart
    Inherits WebPart
    Implements IWebPartRow
    Private _table As DataTable


    Public Sub New()
      _table = New DataTable()

      Dim col As New DataColumn()
      col.DataType = GetType(String)
      col.ColumnName = "Name"
      _table.Columns.Add(col)

      col = New DataColumn()
      col.DataType = GetType(String)
      col.ColumnName = "Address"
      _table.Columns.Add(col)

      col = New DataColumn()
      col.DataType = GetType(Integer)
      col.ColumnName = "ZIP Code"
      _table.Columns.Add(col)

      Dim row As DataRow = _table.NewRow()
      row("Name") = "John Q. Public"
      row("Address") = "123 Main Street"
      row("ZIP Code") = 98000
      _table.Rows.Add(row)

    End Sub


    <ConnectionProvider("Row")> _
    Public Function GetConnectionInterface() As IWebPartRow
      Return New RowProviderWebPart()

    End Function 'GetConnectionInterface


    Public ReadOnly Property Schema() As _
      ComponentModel.PropertyDescriptorCollection Implements IWebPartRow.Schema

      Get
        Return TypeDescriptor.GetProperties(_table.DefaultView(0))
      End Get

    End Property


    Public Sub GetRowData(ByVal callback As RowCallback) _
      Implements IWebPartRow.GetRowData
      callback(_table.Rows)

    End Sub

  End Class


  ' This sample code creates a Web Parts control that acts as a consumer 
  ' of row data.
  <AspNetHostingPermission(SecurityAction.Demand, _
    Level:=AspNetHostingPermissionLevel.Minimal)> _
  <AspNetHostingPermission(SecurityAction.InheritanceDemand, _
    Level:=AspNetHostingPermissionLevel.Minimal)> _
  Public NotInheritable Class RowConsumerWebPart
    Inherits WebPart
    Private _provider As IWebPartRow
    Private _tableData As ICollection


    Private Sub GetRowData(ByVal rowData As Object)
      _tableData = CType(rowData, ICollection)

    End Sub


    Protected Overrides Sub OnPreRender(ByVal e As EventArgs)

      If Not (_provider Is Nothing) Then
        _provider.GetRowData(New RowCallback(AddressOf GetRowData))
      End If

    End Sub

    Protected Overrides Sub RenderContents(ByVal writer As HtmlTextWriter)

      If Not (_provider Is Nothing) Then
        Dim props As PropertyDescriptorCollection = _provider.Schema
        Dim count As Integer = 0
        If Not (props Is Nothing) AndAlso props.Count > 0 _
          AndAlso Not (_tableData Is Nothing) Then

          Dim prop As PropertyDescriptor
          For Each prop In props
            Dim o As DataRow
            For Each o In _tableData
              writer.Write(prop.DisplayName & ": " & o(count))
              writer.WriteBreak()
              writer.WriteLine()
              count = count + 1
            Next o
          Next prop
        Else
          writer.Write("No data")
        End If
      Else
        writer.Write("Not connected")
      End If

    End Sub


    <ConnectionConsumer("Row")> _
    Public Sub SetConnectionInterface(ByVal provider As IWebPartRow)
      _provider = provider

    End Sub

  End Class

End Namespace  ' Samples.AspNet.VB.Controls

Commenti

Utilizzare questo metodo per recuperare i valori delle righe di dati passati dall'interfaccia . Il provider implementa questo metodo e il consumer lo richiama nel momento in cui il consumer è pronto per elaborare o eseguire il rendering dei dati.

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