IWebPartTable.Schema Özellik
Tanım
Önemli
Bazı bilgiler ürünün ön sürümüyle ilgilidir ve sürüm öncesinde önemli değişiklikler yapılmış olabilir. Burada verilen bilgilerle ilgili olarak Microsoft açık veya zımni hiçbir garanti vermez.
İki WebPart denetim arasında veri paylaşmak için kullanılan bir veri tablosunun şema bilgilerini alır.
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
Özellik Değeri
PropertyDescriptorCollection Verileri açıklayan.
Örnekler
Aşağıdaki kod örneği, özelliğinin uygulanmasını ve kullanımını Schema gösterir. Tam örnek, arabirimi için sınıfa genel bakış IWebPartTable bölümünde gösterilmiştir. Sağlayıcı denetimi özelliğini uygular Schema . Ardından tüketici denetimi yönteminde RenderContents
, tablo verilerini sayfaya yazarken tablo hakkındaki bilgileri almak için özelliğini sorgular Schema .
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 table data.
[AspNetHostingPermission(SecurityAction.Demand,
Level = AspNetHostingPermissionLevel.Minimal)]
[AspNetHostingPermission(SecurityAction.InheritanceDemand,
Level = AspNetHostingPermissionLevel.Minimal)]
public sealed class TableProviderWebPart : WebPart, IWebPartTable
{
DataTable _table;
public TableProviderWebPart()
{
_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);
}
public PropertyDescriptorCollection Schema
{
get
{
return TypeDescriptor.GetProperties(_table.DefaultView[0]);
}
}
public void GetTableData(TableCallback callback)
{
callback(_table.Rows);
}
public bool ConnectionPointEnabled
{
get
{
object o = ViewState["ConnectionPointEnabled"];
return (o != null) ? (bool)o : true;
}
set
{
ViewState["ConnectionPointEnabled"] = value;
}
}
[ConnectionProvider("Table", typeof(TableProviderConnectionPoint),
AllowsMultipleConnections = true)]
public IWebPartTable GetConnectionInterface()
{
return new TableProviderWebPart();
}
public class TableProviderConnectionPoint : ProviderConnectionPoint
{
public TableProviderConnectionPoint(MethodInfo callbackMethod,
Type interfaceType, Type controlType, string name, string id,
bool allowsMultipleConnections)
: base(callbackMethod, interfaceType, controlType, name, id,
allowsMultipleConnections)
{
}
public override bool GetEnabled(Control control)
{
return ((TableProviderWebPart)control).ConnectionPointEnabled;
}
}
}
// This code sample creates a Web Parts control that acts as a consumer
// of information provided by the TableProvider.ascx control.
[AspNetHostingPermission(SecurityAction.Demand,
Level = AspNetHostingPermissionLevel.Minimal)]
[AspNetHostingPermission(SecurityAction.InheritanceDemand,
Level = AspNetHostingPermissionLevel.Minimal)]
public class TableConsumer : WebPart
{
private IWebPartTable _provider;
private ICollection _tableData;
private void GetTableData(object tableData)
{
_tableData = (ICollection)tableData;
}
protected override void OnPreRender(EventArgs e)
{
if (_provider != null)
{
_provider.GetTableData(new TableCallback(GetTableData));
}
}
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("Table")]
public void SetConnectionInterface(IWebPartTable provider)
{
_provider = provider;
}
public class TableConsumerConnectionPoint : ConsumerConnectionPoint
{
public TableConsumerConnectionPoint(MethodInfo callbackMethod,
Type interfaceType, Type controlType, string name, string id,
bool allowsMultipleConnections)
: base(callbackMethod, interfaceType, controlType, name, id,
allowsMultipleConnections)
{
}
} // TableConsumerConnectionPoint
} // TableConsumer
} // 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 table data.
<AspNetHostingPermission(SecurityAction.Demand, _
Level:=AspNetHostingPermissionLevel.Minimal)> _
<AspNetHostingPermission(SecurityAction.InheritanceDemand, _
Level:=AspNetHostingPermissionLevel.Minimal)> _
Public NotInheritable Class TableProviderWebPart
Inherits WebPart
Implements IWebPartTable
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
Public ReadOnly Property Schema() As _
ComponentModel.PropertyDescriptorCollection Implements IWebPartTable.Schema
Get
Return TypeDescriptor.GetProperties(_table.DefaultView(0))
End Get
End Property
Public Sub GetTableData(ByVal callback As TableCallback) _
Implements IWebPartTable.GetTableData
callback(_table.Rows)
End Sub
Public Property ConnectionPointEnabled() As Boolean
Get
Dim o As Object = ViewState("ConnectionPointEnabled")
Return IIf(Not (o Is Nothing), CBool(o), True)
End Get
Set(ByVal value As Boolean)
ViewState("ConnectionPointEnabled") = value
End Set
End Property
<ConnectionProvider("Table", GetType(TableProviderConnectionPoint), _
AllowsMultipleConnections:=True)> _
Public Function GetConnectionInterface() As IWebPartTable
Return New TableProviderWebPart()
End Function
End Class
' The connection point for the provider control.
<AspNetHostingPermission(SecurityAction.Demand, _
Level:=AspNetHostingPermissionLevel.Minimal)> _
<AspNetHostingPermission(SecurityAction.InheritanceDemand, _
Level:=AspNetHostingPermissionLevel.Minimal)> _
Public Class TableProviderConnectionPoint
Inherits ProviderConnectionPoint
Public Sub New(ByVal callbackMethod As MethodInfo, _
ByVal interfaceType As Type, ByVal controlType As Type, _
ByVal name As String, ByVal id As String, _
ByVal allowsMultipleConnections As Boolean)
MyBase.New(callbackMethod, interfaceType, controlType, _
name, id, allowsMultipleConnections)
End Sub
Public Overrides Function GetEnabled(ByVal control _
As Control) As Boolean
Return CType(control, TableProviderWebPart).ConnectionPointEnabled
End Function
End Class
' This code sample creates a Web Parts control that acts as a consumer
' of information provided by the TableProvider.ascx control.
<AspNetHostingPermission(SecurityAction.Demand, _
Level:=AspNetHostingPermissionLevel.Minimal)> _
<AspNetHostingPermission(SecurityAction.InheritanceDemand, _
Level:=AspNetHostingPermissionLevel.Minimal)> _
Public Class TableConsumer
Inherits WebPart
Private _provider As IWebPartTable
Private _tableData As ICollection
Private Sub GetTableData(ByVal tableData As ICollection)
_tableData = CType(tableData, ICollection)
End Sub
Protected Overrides Sub OnPreRender(ByVal e As EventArgs)
If Not (_provider Is Nothing) Then
_provider.GetTableData(New TableCallback(AddressOf GetTableData))
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))
Next o
writer.WriteBreak()
writer.WriteLine()
count = count + 1
Next prop
Else
writer.Write("No data")
End If
Else
writer.Write("Not connected")
End If
End Sub
<ConnectionConsumer("Table")> _
Public Sub SetConnectionInterface(ByVal provider As IWebPartTable)
_provider = provider
End Sub
End Class
' The connection point for the consumer control.
<AspNetHostingPermission(SecurityAction.Demand, _
Level:=AspNetHostingPermissionLevel.Minimal)> _
<AspNetHostingPermission(SecurityAction.InheritanceDemand, _
Level:=AspNetHostingPermissionLevel.Minimal)> _
Public Class TableConsumerConnectionPoint
Inherits ConsumerConnectionPoint
Public Sub New(ByVal callbackMethod As MethodInfo, _
ByVal interfaceType As Type, ByVal controlType As Type, _
ByVal name As String, ByVal id As String, _
ByVal allowsMultipleConnections As Boolean)
MyBase.New(callbackMethod, interfaceType, controlType, name, _
id, allowsMultipleConnections)
End Sub
End Class
End Namespace ' Samples.AspNet.CS.Controls
Açıklamalar
Bu özellik, bir IWebPartTable örnekteki veriler hakkında özellik bilgileri sağlar. özelliği tarafından başvurulan şema ile tablodaki Schema veriler arasında örtük bir anlaşma vardır. Anlaşma, özelliğindeki Schema her PropertyDescriptor nesne için tablo verilerinin bir öğesinde çağırarak GetValue tablonun bir sütunundaki veya satırındaki değeri alabilmenizdir.