IWebPartRow.Schema Propriedade

public:
 property System::ComponentModel::PropertyDescriptorCollection ^ Schema { System::ComponentModel::PropertyDescriptorCollection ^ get(); };

public System.ComponentModel.PropertyDescriptorCollection Schema { get; }

member this.Schema : System.ComponentModel.PropertyDescriptorCollection

Public ReadOnly Property Schema As PropertyDescriptorCollection

Valor da propriedade

PropertyDescriptorCollection

Uma PropertyDescriptorCollection descrição dos dados.

Exemplos

O exemplo de código a seguir mostra a implementação e o Schema uso da propriedade. O exemplo completo é mostrado na visão geral da classe para a IWebPartRow interface. O controle do provedor implementa a Schema propriedade. Em seguida, o controle do consumidor, em seu RenderContents método, consulta a Schema propriedade para recuperar informações sobre a linha enquanto grava os dados da linha na página.

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

Comentários

Essa propriedade fornece informações de propriedade para os dados. Usando a IWebPartRow interface em uma conexão, você obtém um PropertyDescriptorCollection objeto, que é referenciado pela Schema propriedade. O contrato especifica que a chamada Schema[n].GetValue(RowData) retorna o valor da nth coluna na linha. Você precisa usar a Schema propriedade para obter os valores na linha.

Aplica-se a

Confira também

• PropertyDescriptorCollection