ObjectDataSource.TypeName Propriedade
Definição
Importante
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Obtém ou define o nome da classe que o objeto ObjectDataSource representa.
public:
property System::String ^ TypeName { System::String ^ get(); void set(System::String ^ value); };public string TypeName { get; set; }member this.TypeName : string with get, setPublic Property TypeName As StringValor da propriedade
Um nome de classe parcial ou totalmente qualificado que identifica o tipo do objeto que o ObjectDataSource representa. O padrão é uma cadeia de caracteres vazia ("").
Exemplos
O exemplo de código a seguir demonstra como um GridView controle pode exibir dados usando um ObjectDataSource controle em uma página do Web Forms. O ObjectDataSource identifica um nome de classe parcial ou totalmente qualificado com sua TypeName propriedade e um método que é chamado para recuperar dados com sua SelectMethod propriedade. Em tempo de execução, o objeto é criado e o método é chamado usando reflexão. O GridView controle enumera pela IEnumerable coleção retornada pela SelectMethod propriedade e exibe os dados.
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS" Assembly="Samples.AspNet.CS" %>
<%@ Page language="c#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>ObjectDataSource - C# Example</title>
</head>
<body>
<form id="Form1" method="post" runat="server">
<asp:gridview
id="GridView1"
runat="server"
datasourceid="ObjectDataSource1" />
<asp:objectdatasource
id="ObjectDataSource1"
runat="server"
selectmethod="GetAllEmployees"
typename="Samples.AspNet.CS.EmployeeLogic" />
</form>
</body>
</html>
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB" Assembly="Samples.AspNet.VB" %>
<%@ Page language="vb" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>ObjectDataSource - Visual Basic Example</title>
</head>
<body>
<form id="Form1" method="post" runat="server">
<asp:gridview
id="GridView1"
runat="server"
datasourceid="ObjectDataSource1" />
<asp:objectdatasource
id="ObjectDataSource1"
runat="server"
selectmethod="GetAllEmployees"
typename="Samples.AspNet.VB.EmployeeLogic" />
</form>
</body>
</html>
O exemplo a seguir mostra a classe à qual o valor da TypeName propriedade se refere.
namespace Samples.AspNet.CS {
using System;
using System.Collections;
using System.Collections.Specialized;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Web.UI;
using System.Web.UI.WebControls;
//
// EmployeeLogic is a stateless business object that encapsulates
// the operations one can perform on a NorthwindEmployee object.
//
public class EmployeeLogic {
// Returns a collection of NorthwindEmployee objects.
public static ICollection GetAllEmployees () {
ArrayList al = new ArrayList();
ConnectionStringSettings cts = ConfigurationManager.ConnectionStrings["NorthwindConnection"];
SqlDataSource sds
= new SqlDataSource(cts.ConnectionString, "SELECT EmployeeID FROM Employees");
try {
IEnumerable IDs = sds.Select(DataSourceSelectArguments.Empty);
// Iterate through the Enumeration and create a
// NorthwindEmployee object for each ID.
foreach (DataRowView row in IDs) {
string id = row["EmployeeID"].ToString();
NorthwindEmployee nwe = new NorthwindEmployee(id);
// Add the NorthwindEmployee object to the collection.
al.Add(nwe);
}
}
finally {
// If anything strange happens, clean up.
sds.Dispose();
}
return al;
}
public static NorthwindEmployee GetEmployee(object anID) {
return new NorthwindEmployee(anID);
}
public static void UpdateEmployeeInfo(NorthwindEmployee ne) {
bool retval = ne.Save();
if (! retval) { throw new NorthwindDataException("UpdateEmployee failed."); }
}
public static void DeleteEmployee(NorthwindEmployee ne) { }
}
public class NorthwindEmployee {
public NorthwindEmployee () {
ID = DBNull.Value;
lastName = "";
firstName = "";
title="";
titleOfCourtesy = "";
reportsTo = -1;
}
public NorthwindEmployee (object anID) {
this.ID = anID;
ConnectionStringSettings cts = ConfigurationManager.ConnectionStrings["NorthwindConnection"];
SqlConnection conn = new SqlConnection (cts.ConnectionString);
SqlCommand sc =
new SqlCommand(" SELECT FirstName,LastName,Title,TitleOfCourtesy,ReportsTo " +
" FROM Employees " +
" WHERE EmployeeID = @empId",
conn);
// Add the employee ID parameter and set its value.
sc.Parameters.Add(new SqlParameter("@empId",SqlDbType.Int)).Value = Int32.Parse(anID.ToString());
SqlDataReader sdr = null;
try {
conn.Open();
sdr = sc.ExecuteReader();
// This is not a while loop. It only loops once.
if (sdr != null && sdr.Read()) {
// The IEnumerable contains DataRowView objects.
this.firstName = sdr["FirstName"].ToString();
this.lastName = sdr["LastName"].ToString();
this.title = sdr["Title"].ToString();
this.titleOfCourtesy = sdr["TitleOfCourtesy"].ToString();
if (! sdr.IsDBNull(4)) {
this.reportsTo = sdr.GetInt32(4);
}
}
else {
throw new NorthwindDataException("Data not loaded for employee id.");
}
}
finally {
try {
if (sdr != null) sdr.Close();
conn.Close();
}
catch (SqlException) {
// Log an event in the Application Event Log.
throw;
}
}
}
private object ID;
private string lastName;
public string LastName {
get { return lastName; }
set { lastName = value; }
}
private string firstName;
public string FirstName {
get { return firstName; }
set { firstName = value; }
}
private string title;
public String Title {
get { return title; }
set { title = value; }
}
private string titleOfCourtesy;
public string Courtesy {
get { return titleOfCourtesy; }
set { titleOfCourtesy = value; }
}
private int reportsTo;
public int Supervisor {
get { return reportsTo; }
set { reportsTo = value; }
}
public bool Save () {
return true;
}
}
internal class NorthwindDataException: Exception {
public NorthwindDataException(string msg) : base (msg) { }
}
}
Imports System.Collections
Imports System.Configuration
Imports System.Data
Imports System.Data.SqlClient
Imports System.Web.UI
Imports System.Web.UI.WebControls
Namespace Samples.AspNet.VB
'
' EmployeeLogic is a stateless business object that encapsulates
' the operations you can perform on a NorthwindEmployee object.
' When the class is written in Visual Basic, you cannot use the Shared
' part.
Public Class EmployeeLogic
' Returns a collection of NorthwindEmployee objects.
Public Shared Function GetAllEmployees() As ICollection
Dim al As New ArrayList()
Dim cts As ConnectionStringSettings = ConfigurationManager.ConnectionStrings("NorthwindConnection")
Dim sds As New SqlDataSource(cts.ConnectionString, "SELECT EmployeeID FROM Employees")
Try
Dim IDs As IEnumerable = sds.Select(DataSourceSelectArguments.Empty)
' Iterate through the Enumeration and create a
' NorthwindEmployee object for each ID.
For Each row As DataRowView In IDs
Dim id As String = row("EmployeeID").ToString()
Dim nwe As New NorthwindEmployee(id)
' Add the NorthwindEmployee object to the collection.
al.Add(nwe)
Next
Finally
' If anything strange happens, clean up.
sds.Dispose()
End Try
Return al
End Function 'GetAllEmployees
Public Shared Function GetEmployee(anID As Object) As NorthwindEmployee
Return New NorthwindEmployee(anID)
End Function 'GetEmployee
Public Shared Sub UpdateEmployeeInfo(ne As NorthwindEmployee)
Dim retval As Boolean = ne.Save()
If Not retval Then
Throw New NorthwindDataException("UpdateEmployee failed.")
End If
End Sub
Public Shared Sub DeleteEmployee(ne As NorthwindEmployee)
End Sub
End Class
Public Class NorthwindEmployee
Public Sub New()
ID = DBNull.Value
aLastName = ""
aFirstName = ""
aTitle = ""
titleOfCourtesy = ""
reportsTo = - 1
End Sub
Public Sub New(anID As Object)
Me.ID = anID
Dim cts As ConnectionStringSettings = ConfigurationManager.ConnectionStrings("NorthwindConnection")
Dim conn As New SqlConnection(cts.ConnectionString)
Dim sc As New SqlCommand(" SELECT FirstName,LastName,Title,TitleOfCourtesy,ReportsTo " & _
" FROM Employees " & _
" WHERE EmployeeID = @empId", conn)
' Add the employee ID parameter and set its value.
sc.Parameters.Add(New SqlParameter("@empId", SqlDbType.Int)).Value = Int32.Parse(anID.ToString())
Dim sdr As SqlDataReader = Nothing
Try
conn.Open()
sdr = sc.ExecuteReader()
' This is not a while loop. It only loops once.
If Not (sdr Is Nothing) AndAlso sdr.Read() Then
' The IEnumerable contains DataRowView objects.
Me.aFirstName = sdr("FirstName").ToString()
Me.aLastName = sdr("LastName").ToString()
Me.aTitle = sdr("Title").ToString()
Me.titleOfCourtesy = sdr("TitleOfCourtesy").ToString()
If Not sdr.IsDBNull(4) Then
Me.reportsTo = sdr.GetInt32(4)
End If
Else
Throw New NorthwindDataException("Data not loaded for employee id.")
End If
Finally
Try
If Not (sdr Is Nothing) Then
sdr.Close()
End If
conn.Close()
Catch se As SqlException
' Log an event in the Application Event Log.
Throw
End Try
End Try
End Sub
Private ID As Object
Private aLastName As String
Public Property LastName() As String
Get
Return aLastName
End Get
Set
aLastName = value
End Set
End Property
Private aFirstName As String
Public Property FirstName() As String
Get
Return aFirstName
End Get
Set
aFirstName = value
End Set
End Property
Private aTitle As String
Public Property Title() As String
Get
Return aTitle
End Get
Set
aTitle = value
End Set
End Property
Private titleOfCourtesy As String
Public Property Courtesy() As String
Get
Return titleOfCourtesy
End Get
Set
titleOfCourtesy = value
End Set
End Property
Private reportsTo As Integer
Public Property Supervisor() As Integer
Get
Return reportsTo
End Get
Set
reportsTo = value
End Set
End Property
Public Function Save() As Boolean
Return True
End Function 'Save
End Class
Friend Class NorthwindDataException
Inherits Exception
Public Sub New(msg As String)
MyBase.New(msg)
End Sub
End Class
End Namespace
Comentários
Para criar uma instância do objeto ao qual o ObjectDataSource controle se associa, o controle usa reflexão para carregar o tipo identificado pelo nome do tipo em tempo de execução. Portanto, o valor da TypeName propriedade pode ser um tipo parcialmente qualificado para o código localizado nos diretórios Bin ou App_Code ou um nome de tipo totalmente qualificado para o código registrado no cache de assembly global. Se você usar o cache de assembly global, deverá adicionar a referência apropriada à assemblies seção do arquivo Machine.config ou Web.config.
O tipo deve ter um construtor sem parâmetros, a menos que você manipule o ObjectCreating evento para criar uma instância dele por conta própria. Uma instância do tipo será criada para cada chamada para os Selectmétodos , Update, Inserte Delete , se os métodos no tipo forem métodos membro. Uma instância não será criada se os métodos forem static (Shared no Visual Basic). Se o tipo implementar a IDisposable interface , o Dispose método será chamado antes que o objeto seja destruído.
Aplica-se a
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