ObjectDataSource.DeleteParameters Eigenschaft
Definition
Wichtig
Einige Informationen beziehen sich auf Vorabversionen, die vor dem Release ggf. grundlegend überarbeitet werden. Microsoft übernimmt hinsichtlich der hier bereitgestellten Informationen keine Gewährleistungen, seien sie ausdrücklich oder konkludent.
Ruft die Parameterauflistung ab, die die von der DeleteMethod-Methode verwendeten Parameter enthält.
public:
property System::Web::UI::WebControls::ParameterCollection ^ DeleteParameters { System::Web::UI::WebControls::ParameterCollection ^ get(); };[System.Web.UI.PersistenceMode(System.Web.UI.PersistenceMode.InnerProperty)]
public System.Web.UI.WebControls.ParameterCollection DeleteParameters { get; }[<System.Web.UI.PersistenceMode(System.Web.UI.PersistenceMode.InnerProperty)>]
member this.DeleteParameters : System.Web.UI.WebControls.ParameterCollectionPublic ReadOnly Property DeleteParameters As ParameterCollectionEigenschaftswert
Eine ParameterCollection, die die von der DeleteMethod-Methode verwendeten Parameter enthält.
- Attribute
Beispiele
Dieser Abschnitt enthält zwei Codebeispiele. Im ersten Codebeispiel wird veranschaulicht, wie Sie ein ObjectDataSource -Objekt mit einem Geschäftsobjekt und einem GridView Steuerelement zum Löschen von Daten verwenden. Das zweite Codebeispiel zeigt die EmployeeLogic Klasse, die im ersten Codebeispiel verwendet wird.
Im folgenden Codebeispiel wird veranschaulicht, wie die DeleteParameters -Eigenschaft des Steuerelements ObjectDataSource mit einem Geschäftsobjekt und einem GridView Steuerelement verwendet wird, um Daten zu löschen. Zunächst zeigt das GridView Steuerelement eine Gruppe aller Mitarbeiter an, wobei die -Methode verwendet wird, die von der SelectMethod -Eigenschaft angegeben wird, um die Daten aus dem EmployeeLogic -Objekt abzurufen. Da die AutoGenerateDeleteButton -Eigenschaft auf truefestgelegt ist, zeigt das GridView Steuerelement automatisch die Schaltfläche Löschen an.
Wenn Sie auf die Schaltfläche Löschen klicken, wird das Deleting Ereignis mit zwei Parametern aufgerufen. Ein Parameter, EmpID, stammt aus dem DataGrid -Steuerelement und basiert auf der DataKeyNames -Eigenschaft. Der andere Parameter stammt aus der deklarativen DeleteParameters Eigenschaft. Die EmployeeLogic -Klasse überlädt die DeleteEmployee -Methode. Eine Überladung akzeptiert einen NorthwindEmployee Parameter, die andere einen Int32 Parameter namens anID.
Deleting Im -Ereignis werden die Einträge in der InputParameters -Eigenschaft so angepasst, dass sie nur einen Parameter mit dem Namen anID mit dem Wert von original_EmpIDenthalten. Wenn der Ereignishandler vorhanden ist, wird die übereinstimmende DeleteEmployee Methode aufgerufen.
Das folgende Codebeispiel zeigt die Webseite, auf der das DataGrid Steuerelement angezeigt und das Deleting Ereignis behandelt wird.
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS" Assembly="Samples.AspNet.CS" %>
<%@ Import namespace="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">
<script runat="server">
private void NorthwindEmployeeDeleting(object source, ObjectDataSourceMethodEventArgs e)
{
IDictionary paramsFromPage = e.InputParameters;
paramsFromPage.Remove("anID");
paramsFromPage.Add("anID", (int)paramsFromPage["EmpID"]);
paramsFromPage.Remove("EmpID");
}
</script>
<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"
autogeneratedeletebutton="true"
DataKeyNames="EmpID">
</asp:gridview>
<asp:objectdatasource
id="ObjectDataSource1"
runat="server"
selectmethod="GetAllEmployees"
deletemethod="DeleteEmployee"
OnDeleting="NorthwindEmployeeDeleting"
typename="Samples.AspNet.CS.EmployeeLogic">
<deleteparameters>
<asp:parameter name="anID" type="Int32" />
</deleteparameters>
</asp:objectdatasource>
</form>
</body>
</html>
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB" Assembly="Samples.AspNet.VB" %>
<%@ Import namespace="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">
<script runat="server">
Private Sub NorthwindEmployeeDeleting(source As Object, e As ObjectDataSourceMethodEventArgs)
Dim paramsFromPage As IDictionary = e.InputParameters
paramsFromPage.Remove("anID")
paramsFromPage.Add("anID", CInt(paramsFromPage("EmpID")))
paramsFromPage.Remove("EmpID")
End Sub ' NorthwindEmployeeDeleting
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>ObjectDataSource - VB Example</title>
</head>
<body>
<form id="Form1" method="post" runat="server">
<asp:gridview
id="GridView1"
runat="server"
datasourceid="ObjectDataSource1"
autogeneratedeletebutton="true"
DataKeyNames="EmpID">
</asp:gridview>
<asp:objectdatasource
id="ObjectDataSource1"
runat="server"
selectmethod="GetAllEmployees"
deletemethod="DeleteEmployee"
OnDeleting="NorthwindEmployeeDeleting"
typename="Samples.AspNet.VB.EmployeeLogic">
<deleteparameters>
<asp:parameter name="anID" type="Int32" />
</deleteparameters>
</asp:objectdatasource>
</form>
</body>
</html>
Das folgende Codebeispiel zeigt die EmployeeLogic Klasse, die im vorherigen Codebeispiel verwendet wird.
namespace Samples.AspNet.CS {
using System;
using System.Collections;
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 you can perform on a NorthwindEmployee object.
//
public class EmployeeLogic {
// Returns a collection of NorthwindEmployee objects.
public static ICollection GetAllEmployees () {
ArrayList al = new ArrayList();
// Use the SqlDataSource class to wrap the
// ADO.NET code required to query the database.
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.
IEnumerator enumerator = IDs.GetEnumerator();
while (enumerator.MoveNext()) {
// The IEnumerable contains DataRowView objects.
DataRowView row = enumerator.Current as DataRowView;
int id = (int) row["EmployeeID"];
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(int anID) {
return new NorthwindEmployee(anID);
}
public static void DeleteEmployee(NorthwindEmployee ne) {
bool retval = ne.Delete();
if (!retval) { throw new NorthwindDataException("Employee delete failed."); }
// Delete the object in memory.
ne = null;
}
public static void DeleteEmployee(int anID) {
NorthwindEmployee tempEmp = new NorthwindEmployee(anID);
DeleteEmployee(tempEmp);
}
}
public class NorthwindEmployee {
public NorthwindEmployee (int anID) {
this.ID = anID;
ConnectionStringSettings cts = ConfigurationManager.ConnectionStrings["NorthwindConnection"];
SqlConnection conn = new SqlConnection (cts.ConnectionString);
SqlCommand sc =
new SqlCommand(" SELECT FirstName,LastName " +
" 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();
}
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;
public object EmpID {
get { return 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; }
}
public bool Delete () {
if (ID.Equals(DBNull.Value)) {
// The Employee object is not persisted.
return true;
}
else {
// The Employee object is persisted.
// Use the SqlDataSource control as a convenient wrapper for
// the ADO.NET code needed to delete a record from the database.
ConnectionStringSettings cts = ConfigurationManager.ConnectionStrings["NorthwindConnection"];
SqlDataSource sds = new SqlDataSource();
try {
sds.ConnectionString = cts.ConnectionString;
sds.DeleteCommand = "DELETE FROM Employees WHERE EmployeeID=@empID;";
sds.DeleteParameters.Add(new Parameter("empID",TypeCode.Int32,this.ID.ToString()));
/* To make this sample fully functional, uncomment these lines
int retval = sds.Delete();
if (retval == 1) { return true; }
return false; */
return true;
}
finally {
sds.Dispose();
}
}
}
}
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.
Public Class EmployeeLogic
' Returns a collection of NorthwindEmployee objects.
Public Shared Function GetAllEmployees() As ICollection
Dim al As New ArrayList()
' Use the SqlDataSource class to wrap the
' ADO.NET code required to query the database.
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.
Dim enumerator As IEnumerator = IDs.GetEnumerator()
While enumerator.MoveNext()
' The IEnumerable contains DataRowView objects.
Dim row As DataRowView = CType(enumerator.Current,DataRowView)
Dim id As String = row("EmployeeID").ToString()
Dim nwe As New NorthwindEmployee(CInt(id))
' Add the NorthwindEmployee object to the collection.
al.Add(nwe)
End While
Finally
' If anything strange happens, clean up.
sds.Dispose()
End Try
Return al
End Function 'GetAllEmployees
Public Shared Function GetEmployee(anID As Integer) As NorthwindEmployee
Return New NorthwindEmployee(anID)
End Function 'GetEmployee
Public Shared Sub DeleteEmployee(ne As NorthwindEmployee)
Dim retval As Boolean = ne.Delete()
If Not retval Then
Throw New NorthwindDataException("Employee delete failed.")
End If ' Delete the object in memory.
ne = Nothing
End Sub
Public Shared Sub DeleteEmployee(anID As Integer)
Dim tempEmp As New NorthwindEmployee(anID)
DeleteEmployee(tempEmp)
End Sub
' And so on...
End Class
Public Class NorthwindEmployee
Public Sub New(anID As Integer)
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 " & _
" 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.firstName = sdr("FirstName").ToString()
Me.lastName = sdr("LastName").ToString()
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
Public ReadOnly Property EmpID() As Object
Get
Return ID
End Get
End Property
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
Public Function Delete() As Boolean
If ID.Equals(DBNull.Value) Then
' The Employee object is not persisted.
Return True
Else
' The Employee object is persisted.
' Use the SqlDataSource control as a convenient wrapper for
' the ADO.NET code needed to delete a record from the database.
Dim cts As ConnectionStringSettings = ConfigurationManager.ConnectionStrings("NorthwindConnection")
Dim sds As New SqlDataSource()
Try
sds.ConnectionString = cts.ConnectionString
sds.DeleteCommand = "DELETE FROM Employees WHERE EmployeeID=@empID;"
Dim param As New Parameter("empID", TypeCode.Int32, CStr(Me.ID))
sds.DeleteParameters.Add(param)
' To make this sample fully functional, uncomment these lines
' int retval = sds.Delete();
' if (retval == 1) { return true; }
' return false;
Return True
Finally
sds.Dispose()
End Try
End If
End Function 'Delete
End Class
Friend Class NorthwindDataException
Inherits Exception
Public Sub New(msg As String)
MyBase.New(msg)
End Sub
End Class
End Namespace
Hinweise
Die Namen und Typen der Parameter, die in der DeleteParameters Auflistung enthalten sind, müssen mit den Namen und Typen der Parameter in der DeleteMethod Methodensignatur übereinstimmen. Die Parameternamen werden von der -Eigenschaft beeinflusst, und die OldValuesParameterFormatString Groß-/Kleinschreibung wird beachtet. Die Parameter in der Auflistung hängen von den Daten im datengebundenen Steuerelement, den deklarativ angegebenen Parametern und den parametern ab, die programmgesteuert hinzugefügt werden. Weitere Informationen finden Sie unter "ParameterZusammenführen" in Delete und Verwenden von Parametern mit dem ObjectDataSource-Steuerelement.
Die DeleteParameters -Eigenschaft ruft die DeleteParameters -Eigenschaft ab, die in dem ObjectDataSourceView -Objekt enthalten ist, das dem ObjectDataSource Steuerelement zugeordnet ist.
Weitere Informationen zum Zusammenführen von Parametern, zur Objektlebensdauer und zur Methodenauflösung finden Sie unter DeleteMethod.
